GNU Linux-libre 4.4.288-gnu1

[releases.git] / arch / powerpc / kvm / book3s_hv.c

/*
 * Copyright 2011 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
 * Copyright (C) 2009. SUSE Linux Products GmbH. All rights reserved.
 *
 * Authors:
 *    Paul Mackerras <paulus@au1.ibm.com>
 *    Alexander Graf <agraf@suse.de>
 *    Kevin Wolf <mail@kevin-wolf.de>
 *
 * Description: KVM functions specific to running on Book 3S
 * processors in hypervisor mode (specifically POWER7 and later).
 *
 * This file is derived from arch/powerpc/kvm/book3s.c,
 * by Alexander Graf <agraf@suse.de>.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation.
 */

#include <linux/kvm_host.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/preempt.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/anon_inodes.h>
#include <linux/cpumask.h>
#include <linux/spinlock.h>
#include <linux/page-flags.h>
#include <linux/srcu.h>
#include <linux/miscdevice.h>
#include <linux/debugfs.h>

#include <asm/reg.h>
#include <asm/cputable.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include <asm/mmu_context.h>
#include <asm/lppaca.h>
#include <asm/processor.h>
#include <asm/cputhreads.h>
#include <asm/page.h>
#include <asm/hvcall.h>
#include <asm/switch_to.h>
#include <asm/smp.h>
#include <asm/dbell.h>
#include <linux/gfp.h>
#include <linux/vmalloc.h>
#include <linux/highmem.h>
#include <linux/hugetlb.h>
#include <linux/module.h>

#include "book3s.h"

#define CREATE_TRACE_POINTS
#include "trace_hv.h"

/* #define EXIT_DEBUG */
/* #define EXIT_DEBUG_SIMPLE */
/* #define EXIT_DEBUG_INT */

/* Used to indicate that a guest page fault needs to be handled */
#define RESUME_PAGE_FAULT       (RESUME_GUEST | RESUME_FLAG_ARCH1)

/* Used as a "null" value for timebase values */
#define TB_NIL  (~(u64)0)

static DECLARE_BITMAP(default_enabled_hcalls, MAX_HCALL_OPCODE/4 + 1);

static int dynamic_mt_modes = 6;
module_param(dynamic_mt_modes, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(dynamic_mt_modes, "Set of allowed dynamic micro-threading modes: 0 (= none), 2, 4, or 6 (= 2 or 4)");
static int target_smt_mode;
module_param(target_smt_mode, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(target_smt_mode, "Target threads per core (0 = max)");

static void kvmppc_end_cede(struct kvm_vcpu *vcpu);
static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu);

static bool kvmppc_ipi_thread(int cpu)
{
        /* On POWER8 for IPIs to threads in the same core, use msgsnd */
        if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
                preempt_disable();
                if (cpu_first_thread_sibling(cpu) ==
                    cpu_first_thread_sibling(smp_processor_id())) {
                        unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);
                        msg |= cpu_thread_in_core(cpu);
                        smp_mb();
                        __asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg));
                        preempt_enable();
                        return true;
                }
                preempt_enable();
        }

#if defined(CONFIG_PPC_ICP_NATIVE) && defined(CONFIG_SMP)
        if (cpu >= 0 && cpu < nr_cpu_ids && paca[cpu].kvm_hstate.xics_phys) {
                xics_wake_cpu(cpu);
                return true;
        }
#endif

        return false;
}

static void kvmppc_fast_vcpu_kick_hv(struct kvm_vcpu *vcpu)
{
        int cpu;
        wait_queue_head_t *wqp;

        wqp = kvm_arch_vcpu_wq(vcpu);
        if (waitqueue_active(wqp)) {
                wake_up_interruptible(wqp);
                ++vcpu->stat.halt_wakeup;
        }

        if (kvmppc_ipi_thread(vcpu->arch.thread_cpu))
                return;

        /* CPU points to the first thread of the core */
        cpu = vcpu->cpu;
        if (cpu >= 0 && cpu < nr_cpu_ids && cpu_online(cpu))
                smp_send_reschedule(cpu);
}

/*
 * We use the vcpu_load/put functions to measure stolen time.
 * Stolen time is counted as time when either the vcpu is able to
 * run as part of a virtual core, but the task running the vcore
 * is preempted or sleeping, or when the vcpu needs something done
 * in the kernel by the task running the vcpu, but that task is
 * preempted or sleeping.  Those two things have to be counted
 * separately, since one of the vcpu tasks will take on the job
 * of running the core, and the other vcpu tasks in the vcore will
 * sleep waiting for it to do that, but that sleep shouldn't count
 * as stolen time.
 *
 * Hence we accumulate stolen time when the vcpu can run as part of
 * a vcore using vc->stolen_tb, and the stolen time when the vcpu
 * needs its task to do other things in the kernel (for example,
 * service a page fault) in busy_stolen.  We don't accumulate
 * stolen time for a vcore when it is inactive, or for a vcpu
 * when it is in state RUNNING or NOTREADY.  NOTREADY is a bit of
 * a misnomer; it means that the vcpu task is not executing in
 * the KVM_VCPU_RUN ioctl, i.e. it is in userspace or elsewhere in
 * the kernel.  We don't have any way of dividing up that time
 * between time that the vcpu is genuinely stopped, time that
 * the task is actively working on behalf of the vcpu, and time
 * that the task is preempted, so we don't count any of it as
 * stolen.
 *
 * Updates to busy_stolen are protected by arch.tbacct_lock;
 * updates to vc->stolen_tb are protected by the vcore->stoltb_lock
 * lock.  The stolen times are measured in units of timebase ticks.
 * (Note that the != TB_NIL checks below are purely defensive;
 * they should never fail.)
 */

static void kvmppc_core_start_stolen(struct kvmppc_vcore *vc)
{
        unsigned long flags;

        spin_lock_irqsave(&vc->stoltb_lock, flags);
        vc->preempt_tb = mftb();
        spin_unlock_irqrestore(&vc->stoltb_lock, flags);
}

static void kvmppc_core_end_stolen(struct kvmppc_vcore *vc)
{
        unsigned long flags;

        spin_lock_irqsave(&vc->stoltb_lock, flags);
        if (vc->preempt_tb != TB_NIL) {
                vc->stolen_tb += mftb() - vc->preempt_tb;
                vc->preempt_tb = TB_NIL;
        }
        spin_unlock_irqrestore(&vc->stoltb_lock, flags);
}

static void kvmppc_core_vcpu_load_hv(struct kvm_vcpu *vcpu, int cpu)
{
        struct kvmppc_vcore *vc = vcpu->arch.vcore;
        unsigned long flags;

        /*
         * We can test vc->runner without taking the vcore lock,
         * because only this task ever sets vc->runner to this
         * vcpu, and once it is set to this vcpu, only this task
         * ever sets it to NULL.
         */
        if (vc->runner == vcpu && vc->vcore_state >= VCORE_SLEEPING)
                kvmppc_core_end_stolen(vc);

        spin_lock_irqsave(&vcpu->arch.tbacct_lock, flags);
        if (vcpu->arch.state == KVMPPC_VCPU_BUSY_IN_HOST &&
            vcpu->arch.busy_preempt != TB_NIL) {
                vcpu->arch.busy_stolen += mftb() - vcpu->arch.busy_preempt;
                vcpu->arch.busy_preempt = TB_NIL;
        }
        spin_unlock_irqrestore(&vcpu->arch.tbacct_lock, flags);
}

static void kvmppc_core_vcpu_put_hv(struct kvm_vcpu *vcpu)
{
        struct kvmppc_vcore *vc = vcpu->arch.vcore;
        unsigned long flags;

        if (vc->runner == vcpu && vc->vcore_state >= VCORE_SLEEPING)
                kvmppc_core_start_stolen(vc);

        spin_lock_irqsave(&vcpu->arch.tbacct_lock, flags);
        if (vcpu->arch.state == KVMPPC_VCPU_BUSY_IN_HOST)
                vcpu->arch.busy_preempt = mftb();
        spin_unlock_irqrestore(&vcpu->arch.tbacct_lock, flags);
}

static void kvmppc_set_msr_hv(struct kvm_vcpu *vcpu, u64 msr)
{
        /*
         * Check for illegal transactional state bit combination
         * and if we find it, force the TS field to a safe state.
         */
        if ((msr & MSR_TS_MASK) == MSR_TS_MASK)
                msr &= ~MSR_TS_MASK;
        vcpu->arch.shregs.msr = msr;
        kvmppc_end_cede(vcpu);
}

static void kvmppc_set_pvr_hv(struct kvm_vcpu *vcpu, u32 pvr)
{
        vcpu->arch.pvr = pvr;
}

static int kvmppc_set_arch_compat(struct kvm_vcpu *vcpu, u32 arch_compat)
{
        unsigned long pcr = 0;
        struct kvmppc_vcore *vc = vcpu->arch.vcore;

        if (arch_compat) {
                switch (arch_compat) {
                case PVR_ARCH_205:
                        /*
                         * If an arch bit is set in PCR, all the defined
                         * higher-order arch bits also have to be set.
                         */
                        pcr = PCR_ARCH_206 | PCR_ARCH_205;
                        break;
                case PVR_ARCH_206:
                case PVR_ARCH_206p:
                        pcr = PCR_ARCH_206;
                        break;
                case PVR_ARCH_207:
                        break;
                default:
                        return -EINVAL;
                }

                if (!cpu_has_feature(CPU_FTR_ARCH_207S)) {
                        /* POWER7 can't emulate POWER8 */
                        if (!(pcr & PCR_ARCH_206))
                                return -EINVAL;
                        pcr &= ~PCR_ARCH_206;
                }
        }

        spin_lock(&vc->lock);
        vc->arch_compat = arch_compat;
        vc->pcr = pcr;
        spin_unlock(&vc->lock);

        return 0;
}

static void kvmppc_dump_regs(struct kvm_vcpu *vcpu)
{
        int r;

        pr_err("vcpu %p (%d):\n", vcpu, vcpu->vcpu_id);
        pr_err("pc  = %.16lx  msr = %.16llx  trap = %x\n",
               vcpu->arch.pc, vcpu->arch.shregs.msr, vcpu->arch.trap);
        for (r = 0; r < 16; ++r)
                pr_err("r%2d = %.16lx  r%d = %.16lx\n",
                       r, kvmppc_get_gpr(vcpu, r),
                       r+16, kvmppc_get_gpr(vcpu, r+16));
        pr_err("ctr = %.16lx  lr  = %.16lx\n",
               vcpu->arch.ctr, vcpu->arch.lr);
        pr_err("srr0 = %.16llx srr1 = %.16llx\n",
               vcpu->arch.shregs.srr0, vcpu->arch.shregs.srr1);
        pr_err("sprg0 = %.16llx sprg1 = %.16llx\n",
               vcpu->arch.shregs.sprg0, vcpu->arch.shregs.sprg1);
        pr_err("sprg2 = %.16llx sprg3 = %.16llx\n",
               vcpu->arch.shregs.sprg2, vcpu->arch.shregs.sprg3);
        pr_err("cr = %.8x  xer = %.16lx  dsisr = %.8x\n",
               vcpu->arch.cr, vcpu->arch.xer, vcpu->arch.shregs.dsisr);
        pr_err("dar = %.16llx\n", vcpu->arch.shregs.dar);
        pr_err("fault dar = %.16lx dsisr = %.8x\n",
               vcpu->arch.fault_dar, vcpu->arch.fault_dsisr);
        pr_err("SLB (%d entries):\n", vcpu->arch.slb_max);
        for (r = 0; r < vcpu->arch.slb_max; ++r)
                pr_err("  ESID = %.16llx VSID = %.16llx\n",
                       vcpu->arch.slb[r].orige, vcpu->arch.slb[r].origv);
        pr_err("lpcr = %.16lx sdr1 = %.16lx last_inst = %.8x\n",
               vcpu->arch.vcore->lpcr, vcpu->kvm->arch.sdr1,
               vcpu->arch.last_inst);
}

static struct kvm_vcpu *kvmppc_find_vcpu(struct kvm *kvm, int id)
{
        int r;
        struct kvm_vcpu *v, *ret = NULL;

        mutex_lock(&kvm->lock);
        kvm_for_each_vcpu(r, v, kvm) {
                if (v->vcpu_id == id) {
                        ret = v;
                        break;
                }
        }
        mutex_unlock(&kvm->lock);
        return ret;
}

static void init_vpa(struct kvm_vcpu *vcpu, struct lppaca *vpa)
{
        vpa->__old_status |= LPPACA_OLD_SHARED_PROC;
        vpa->yield_count = cpu_to_be32(1);
}

static int set_vpa(struct kvm_vcpu *vcpu, struct kvmppc_vpa *v,
                   unsigned long addr, unsigned long len)
{
        /* check address is cacheline aligned */
        if (addr & (L1_CACHE_BYTES - 1))
                return -EINVAL;
        spin_lock(&vcpu->arch.vpa_update_lock);
        if (v->next_gpa != addr || v->len != len) {
                v->next_gpa = addr;
                v->len = addr ? len : 0;
                v->update_pending = 1;
        }
        spin_unlock(&vcpu->arch.vpa_update_lock);
        return 0;
}

/* Length for a per-processor buffer is passed in at offset 4 in the buffer */
struct reg_vpa {
        u32 dummy;
        union {
                __be16 hword;
                __be32 word;
        } length;
};

static int vpa_is_registered(struct kvmppc_vpa *vpap)
{
        if (vpap->update_pending)
                return vpap->next_gpa != 0;
        return vpap->pinned_addr != NULL;
}

static unsigned long do_h_register_vpa(struct kvm_vcpu *vcpu,
                                       unsigned long flags,
                                       unsigned long vcpuid, unsigned long vpa)
{
        struct kvm *kvm = vcpu->kvm;
        unsigned long len, nb;
        void *va;
        struct kvm_vcpu *tvcpu;
        int err;
        int subfunc;
        struct kvmppc_vpa *vpap;

        tvcpu = kvmppc_find_vcpu(kvm, vcpuid);
        if (!tvcpu)
                return H_PARAMETER;

        subfunc = (flags >> H_VPA_FUNC_SHIFT) & H_VPA_FUNC_MASK;
        if (subfunc == H_VPA_REG_VPA || subfunc == H_VPA_REG_DTL ||
            subfunc == H_VPA_REG_SLB) {
                /* Registering new area - address must be cache-line aligned */
                if ((vpa & (L1_CACHE_BYTES - 1)) || !vpa)
                        return H_PARAMETER;

                /* convert logical addr to kernel addr and read length */
                va = kvmppc_pin_guest_page(kvm, vpa, &nb);
                if (va == NULL)
                        return H_PARAMETER;
                if (subfunc == H_VPA_REG_VPA)
                        len = be16_to_cpu(((struct reg_vpa *)va)->length.hword);
                else
                        len = be32_to_cpu(((struct reg_vpa *)va)->length.word);
                kvmppc_unpin_guest_page(kvm, va, vpa, false);

                /* Check length */
                if (len > nb || len < sizeof(struct reg_vpa))
                        return H_PARAMETER;
        } else {
                vpa = 0;
                len = 0;
        }

        err = H_PARAMETER;
        vpap = NULL;
        spin_lock(&tvcpu->arch.vpa_update_lock);

        switch (subfunc) {
        case H_VPA_REG_VPA:             /* register VPA */
                if (len < sizeof(struct lppaca))
                        break;
                vpap = &tvcpu->arch.vpa;
                err = 0;
                break;

        case H_VPA_REG_DTL:             /* register DTL */
                if (len < sizeof(struct dtl_entry))
                        break;
                len -= len % sizeof(struct dtl_entry);

                /* Check that they have previously registered a VPA */
                err = H_RESOURCE;
                if (!vpa_is_registered(&tvcpu->arch.vpa))
                        break;

                vpap = &tvcpu->arch.dtl;
                err = 0;
                break;

        case H_VPA_REG_SLB:             /* register SLB shadow buffer */
                /* Check that they have previously registered a VPA */
                err = H_RESOURCE;
                if (!vpa_is_registered(&tvcpu->arch.vpa))
                        break;

                vpap = &tvcpu->arch.slb_shadow;
                err = 0;
                break;

        case H_VPA_DEREG_VPA:           /* deregister VPA */
                /* Check they don't still have a DTL or SLB buf registered */
                err = H_RESOURCE;
                if (vpa_is_registered(&tvcpu->arch.dtl) ||
                    vpa_is_registered(&tvcpu->arch.slb_shadow))
                        break;

                vpap = &tvcpu->arch.vpa;
                err = 0;
                break;

        case H_VPA_DEREG_DTL:           /* deregister DTL */
                vpap = &tvcpu->arch.dtl;
                err = 0;
                break;

        case H_VPA_DEREG_SLB:           /* deregister SLB shadow buffer */
                vpap = &tvcpu->arch.slb_shadow;
                err = 0;
                break;
        }

        if (vpap) {
                vpap->next_gpa = vpa;
                vpap->len = len;
                vpap->update_pending = 1;
        }

        spin_unlock(&tvcpu->arch.vpa_update_lock);

        return err;
}

static void kvmppc_update_vpa(struct kvm_vcpu *vcpu, struct kvmppc_vpa *vpap)
{
        struct kvm *kvm = vcpu->kvm;
        void *va;
        unsigned long nb;
        unsigned long gpa;

        /*
         * We need to pin the page pointed to by vpap->next_gpa,
         * but we can't call kvmppc_pin_guest_page under the lock
         * as it does get_user_pages() and down_read().  So we
         * have to drop the lock, pin the page, then get the lock
         * again and check that a new area didn't get registered
         * in the meantime.
         */
        for (;;) {
                gpa = vpap->next_gpa;
                spin_unlock(&vcpu->arch.vpa_update_lock);
                va = NULL;
                nb = 0;
                if (gpa)
                        va = kvmppc_pin_guest_page(kvm, gpa, &nb);
                spin_lock(&vcpu->arch.vpa_update_lock);
                if (gpa == vpap->next_gpa)
                        break;
                /* sigh... unpin that one and try again */
                if (va)
                        kvmppc_unpin_guest_page(kvm, va, gpa, false);
        }

        vpap->update_pending = 0;
        if (va && nb < vpap->len) {
                /*
                 * If it's now too short, it must be that userspace
                 * has changed the mappings underlying guest memory,
                 * so unregister the region.
                 */
                kvmppc_unpin_guest_page(kvm, va, gpa, false);
                va = NULL;
        }
        if (vpap->pinned_addr)
                kvmppc_unpin_guest_page(kvm, vpap->pinned_addr, vpap->gpa,
                                        vpap->dirty);
        vpap->gpa = gpa;
        vpap->pinned_addr = va;
        vpap->dirty = false;
        if (va)
                vpap->pinned_end = va + vpap->len;
}

static void kvmppc_update_vpas(struct kvm_vcpu *vcpu)
{
        if (!(vcpu->arch.vpa.update_pending ||
              vcpu->arch.slb_shadow.update_pending ||
              vcpu->arch.dtl.update_pending))
                return;

        spin_lock(&vcpu->arch.vpa_update_lock);
        if (vcpu->arch.vpa.update_pending) {
                kvmppc_update_vpa(vcpu, &vcpu->arch.vpa);
                if (vcpu->arch.vpa.pinned_addr)
                        init_vpa(vcpu, vcpu->arch.vpa.pinned_addr);
        }
        if (vcpu->arch.dtl.update_pending) {
                kvmppc_update_vpa(vcpu, &vcpu->arch.dtl);
                vcpu->arch.dtl_ptr = vcpu->arch.dtl.pinned_addr;
                vcpu->arch.dtl_index = 0;
        }
        if (vcpu->arch.slb_shadow.update_pending)
                kvmppc_update_vpa(vcpu, &vcpu->arch.slb_shadow);
        spin_unlock(&vcpu->arch.vpa_update_lock);
}

/*
 * Return the accumulated stolen time for the vcore up until `now'.
 * The caller should hold the vcore lock.
 */
static u64 vcore_stolen_time(struct kvmppc_vcore *vc, u64 now)
{
        u64 p;
        unsigned long flags;

        spin_lock_irqsave(&vc->stoltb_lock, flags);
        p = vc->stolen_tb;
        if (vc->vcore_state != VCORE_INACTIVE &&
            vc->preempt_tb != TB_NIL)
                p += now - vc->preempt_tb;
        spin_unlock_irqrestore(&vc->stoltb_lock, flags);
        return p;
}

static void kvmppc_create_dtl_entry(struct kvm_vcpu *vcpu,
                                    struct kvmppc_vcore *vc)
{
        struct dtl_entry *dt;
        struct lppaca *vpa;
        unsigned long stolen;
        unsigned long core_stolen;
        u64 now;

        dt = vcpu->arch.dtl_ptr;
        vpa = vcpu->arch.vpa.pinned_addr;
        now = mftb();
        core_stolen = vcore_stolen_time(vc, now);
        stolen = core_stolen - vcpu->arch.stolen_logged;
        vcpu->arch.stolen_logged = core_stolen;
        spin_lock_irq(&vcpu->arch.tbacct_lock);
        stolen += vcpu->arch.busy_stolen;
        vcpu->arch.busy_stolen = 0;
        spin_unlock_irq(&vcpu->arch.tbacct_lock);
        if (!dt || !vpa)
                return;
        memset(dt, 0, sizeof(struct dtl_entry));
        dt->dispatch_reason = 7;
        dt->processor_id = cpu_to_be16(vc->pcpu + vcpu->arch.ptid);
        dt->timebase = cpu_to_be64(now + vc->tb_offset);
        dt->enqueue_to_dispatch_time = cpu_to_be32(stolen);
        dt->srr0 = cpu_to_be64(kvmppc_get_pc(vcpu));
        dt->srr1 = cpu_to_be64(vcpu->arch.shregs.msr);
        ++dt;
        if (dt == vcpu->arch.dtl.pinned_end)
                dt = vcpu->arch.dtl.pinned_addr;
        vcpu->arch.dtl_ptr = dt;
        /* order writing *dt vs. writing vpa->dtl_idx */
        smp_wmb();
        vpa->dtl_idx = cpu_to_be64(++vcpu->arch.dtl_index);
        vcpu->arch.dtl.dirty = true;
}

static bool kvmppc_power8_compatible(struct kvm_vcpu *vcpu)
{
        if (vcpu->arch.vcore->arch_compat >= PVR_ARCH_207)
                return true;
        if ((!vcpu->arch.vcore->arch_compat) &&
            cpu_has_feature(CPU_FTR_ARCH_207S))
                return true;
        return false;
}

static int kvmppc_h_set_mode(struct kvm_vcpu *vcpu, unsigned long mflags,
                             unsigned long resource, unsigned long value1,
                             unsigned long value2)
{
        switch (resource) {
        case H_SET_MODE_RESOURCE_SET_CIABR:
                if (!kvmppc_power8_compatible(vcpu))
                        return H_P2;
                if (value2)
                        return H_P4;
                if (mflags)
                        return H_UNSUPPORTED_FLAG_START;
                /* Guests can't breakpoint the hypervisor */
                if ((value1 & CIABR_PRIV) == CIABR_PRIV_HYPER)
                        return H_P3;
                vcpu->arch.ciabr  = value1;
                return H_SUCCESS;
        case H_SET_MODE_RESOURCE_SET_DAWR:
                if (!kvmppc_power8_compatible(vcpu))
                        return H_P2;
                if (mflags)
                        return H_UNSUPPORTED_FLAG_START;
                if (value2 & DABRX_HYP)
                        return H_P4;
                vcpu->arch.dawr  = value1;
                vcpu->arch.dawrx = value2;
                return H_SUCCESS;
        default:
                return H_TOO_HARD;
        }
}

static int kvm_arch_vcpu_yield_to(struct kvm_vcpu *target)
{
        struct kvmppc_vcore *vcore = target->arch.vcore;

        /*
         * We expect to have been called by the real mode handler
         * (kvmppc_rm_h_confer()) which would have directly returned
         * H_SUCCESS if the source vcore wasn't idle (e.g. if it may
         * have useful work to do and should not confer) so we don't
         * recheck that here.
         */

        spin_lock(&vcore->lock);
        if (target->arch.state == KVMPPC_VCPU_RUNNABLE &&
            vcore->vcore_state != VCORE_INACTIVE &&
            vcore->runner)
                target = vcore->runner;
        spin_unlock(&vcore->lock);

        return kvm_vcpu_yield_to(target);
}

static int kvmppc_get_yield_count(struct kvm_vcpu *vcpu)
{
        int yield_count = 0;
        struct lppaca *lppaca;

        spin_lock(&vcpu->arch.vpa_update_lock);
        lppaca = (struct lppaca *)vcpu->arch.vpa.pinned_addr;
        if (lppaca)
                yield_count = be32_to_cpu(lppaca->yield_count);
        spin_unlock(&vcpu->arch.vpa_update_lock);
        return yield_count;
}

int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
{
        unsigned long req = kvmppc_get_gpr(vcpu, 3);
        unsigned long target, ret = H_SUCCESS;
        int yield_count;
        struct kvm_vcpu *tvcpu;
        int idx, rc;

        if (req <= MAX_HCALL_OPCODE &&
            !test_bit(req/4, vcpu->kvm->arch.enabled_hcalls))
                return RESUME_HOST;

        switch (req) {
        case H_CEDE:
                break;
        case H_PROD:
                target = kvmppc_get_gpr(vcpu, 4);
                tvcpu = kvmppc_find_vcpu(vcpu->kvm, target);
                if (!tvcpu) {
                        ret = H_PARAMETER;
                        break;
                }
                tvcpu->arch.prodded = 1;
                smp_mb();
                if (vcpu->arch.ceded) {
                        if (waitqueue_active(&vcpu->wq)) {
                                wake_up_interruptible(&vcpu->wq);
                                vcpu->stat.halt_wakeup++;
                        }
                }
                break;
        case H_CONFER:
                target = kvmppc_get_gpr(vcpu, 4);
                if (target == -1)
                        break;
                tvcpu = kvmppc_find_vcpu(vcpu->kvm, target);
                if (!tvcpu) {
                        ret = H_PARAMETER;
                        break;
                }
                yield_count = kvmppc_get_gpr(vcpu, 5);
                if (kvmppc_get_yield_count(tvcpu) != yield_count)
                        break;
                kvm_arch_vcpu_yield_to(tvcpu);
                break;
        case H_REGISTER_VPA:
                ret = do_h_register_vpa(vcpu, kvmppc_get_gpr(vcpu, 4),
                                        kvmppc_get_gpr(vcpu, 5),
                                        kvmppc_get_gpr(vcpu, 6));
                break;
        case H_RTAS:
                if (list_empty(&vcpu->kvm->arch.rtas_tokens))
                        return RESUME_HOST;

                idx = srcu_read_lock(&vcpu->kvm->srcu);
                rc = kvmppc_rtas_hcall(vcpu);
                srcu_read_unlock(&vcpu->kvm->srcu, idx);

                if (rc == -ENOENT)
                        return RESUME_HOST;
                else if (rc == 0)
                        break;

                /* Send the error out to userspace via KVM_RUN */
                return rc;
        case H_LOGICAL_CI_LOAD:
                ret = kvmppc_h_logical_ci_load(vcpu);
                if (ret == H_TOO_HARD)
                        return RESUME_HOST;
                break;
        case H_LOGICAL_CI_STORE:
                ret = kvmppc_h_logical_ci_store(vcpu);
                if (ret == H_TOO_HARD)
                        return RESUME_HOST;
                break;
        case H_SET_MODE:
                ret = kvmppc_h_set_mode(vcpu, kvmppc_get_gpr(vcpu, 4),
                                        kvmppc_get_gpr(vcpu, 5),
                                        kvmppc_get_gpr(vcpu, 6),
                                        kvmppc_get_gpr(vcpu, 7));
                if (ret == H_TOO_HARD)
                        return RESUME_HOST;
                break;
        case H_XIRR:
        case H_CPPR:
        case H_EOI:
        case H_IPI:
        case H_IPOLL:
        case H_XIRR_X:
                if (kvmppc_xics_enabled(vcpu)) {
                        ret = kvmppc_xics_hcall(vcpu, req);
                        break;
                } /* fallthrough */
        default:
                return RESUME_HOST;
        }
        kvmppc_set_gpr(vcpu, 3, ret);
        vcpu->arch.hcall_needed = 0;
        return RESUME_GUEST;
}

static int kvmppc_hcall_impl_hv(unsigned long cmd)
{
        switch (cmd) {
        case H_CEDE:
        case H_PROD:
        case H_CONFER:
        case H_REGISTER_VPA:
        case H_SET_MODE:
        case H_LOGICAL_CI_LOAD:
        case H_LOGICAL_CI_STORE:
#ifdef CONFIG_KVM_XICS
        case H_XIRR:
        case H_CPPR:
        case H_EOI:
        case H_IPI:
        case H_IPOLL:
        case H_XIRR_X:
#endif
                return 1;
        }

        /* See if it's in the real-mode table */
        return kvmppc_hcall_impl_hv_realmode(cmd);
}

static int kvmppc_emulate_debug_inst(struct kvm_run *run,
                                        struct kvm_vcpu *vcpu)
{
        u32 last_inst;

        if (kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst) !=
                                        EMULATE_DONE) {
                /*
                 * Fetch failed, so return to guest and
                 * try executing it again.
                 */
                return RESUME_GUEST;
        }

        if (last_inst == KVMPPC_INST_SW_BREAKPOINT) {
                run->exit_reason = KVM_EXIT_DEBUG;
                run->debug.arch.address = kvmppc_get_pc(vcpu);
                return RESUME_HOST;
        } else {
                kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
                return RESUME_GUEST;
        }
}

static int kvmppc_handle_exit_hv(struct kvm_run *run, struct kvm_vcpu *vcpu,
                                 struct task_struct *tsk)
{
        int r = RESUME_HOST;

        vcpu->stat.sum_exits++;

        run->exit_reason = KVM_EXIT_UNKNOWN;
        run->ready_for_interrupt_injection = 1;
        switch (vcpu->arch.trap) {
        /* We're good on these - the host merely wanted to get our attention */
        case BOOK3S_INTERRUPT_HV_DECREMENTER:
                vcpu->stat.dec_exits++;
                r = RESUME_GUEST;
                break;
        case BOOK3S_INTERRUPT_EXTERNAL:
        case BOOK3S_INTERRUPT_H_DOORBELL:
                vcpu->stat.ext_intr_exits++;
                r = RESUME_GUEST;
                break;
        /* HMI is hypervisor interrupt and host has handled it. Resume guest.*/
        case BOOK3S_INTERRUPT_HMI:
        case BOOK3S_INTERRUPT_PERFMON:
                r = RESUME_GUEST;
                break;
        case BOOK3S_INTERRUPT_MACHINE_CHECK:
                /*
                 * Deliver a machine check interrupt to the guest.
                 * We have to do this, even if the host has handled the
                 * machine check, because machine checks use SRR0/1 and
                 * the interrupt might have trashed guest state in them.
                 */
                kvmppc_book3s_queue_irqprio(vcpu,
                                            BOOK3S_INTERRUPT_MACHINE_CHECK);
                r = RESUME_GUEST;
                break;
        case BOOK3S_INTERRUPT_PROGRAM:
        {
                ulong flags;
                /*
                 * Normally program interrupts are delivered directly
                 * to the guest by the hardware, but we can get here
                 * as a result of a hypervisor emulation interrupt
                 * (e40) getting turned into a 700 by BML RTAS.
                 */
                flags = vcpu->arch.shregs.msr & 0x1f0000ull;
                kvmppc_core_queue_program(vcpu, flags);
                r = RESUME_GUEST;
                break;
        }
        case BOOK3S_INTERRUPT_SYSCALL:
        {
                /* hcall - punt to userspace */
                int i;

                /* hypercall with MSR_PR has already been handled in rmode,
                 * and never reaches here.
                 */

                run->papr_hcall.nr = kvmppc_get_gpr(vcpu, 3);
                for (i = 0; i < 9; ++i)
                        run->papr_hcall.args[i] = kvmppc_get_gpr(vcpu, 4 + i);
                run->exit_reason = KVM_EXIT_PAPR_HCALL;
                vcpu->arch.hcall_needed = 1;
                r = RESUME_HOST;
                break;
        }
        /*
         * We get these next two if the guest accesses a page which it thinks
         * it has mapped but which is not actually present, either because
         * it is for an emulated I/O device or because the corresonding
         * host page has been paged out.  Any other HDSI/HISI interrupts
         * have been handled already.
         */
        case BOOK3S_INTERRUPT_H_DATA_STORAGE:
                r = RESUME_PAGE_FAULT;
                break;
        case BOOK3S_INTERRUPT_H_INST_STORAGE:
                vcpu->arch.fault_dar = kvmppc_get_pc(vcpu);
                vcpu->arch.fault_dsisr = 0;
                r = RESUME_PAGE_FAULT;
                break;
        /*
         * This occurs if the guest executes an illegal instruction.
         * If the guest debug is disabled, generate a program interrupt
         * to the guest. If guest debug is enabled, we need to check
         * whether the instruction is a software breakpoint instruction.
         * Accordingly return to Guest or Host.
         */
        case BOOK3S_INTERRUPT_H_EMUL_ASSIST:
                if (vcpu->arch.emul_inst != KVM_INST_FETCH_FAILED)
                        vcpu->arch.last_inst = kvmppc_need_byteswap(vcpu) ?
                                swab32(vcpu->arch.emul_inst) :
                                vcpu->arch.emul_inst;
                if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) {
                        r = kvmppc_emulate_debug_inst(run, vcpu);
                } else {
                        kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
                        r = RESUME_GUEST;
                }
                break;
        /*
         * This occurs if the guest (kernel or userspace), does something that
         * is prohibited by HFSCR.  We just generate a program interrupt to
         * the guest.
         */
        case BOOK3S_INTERRUPT_H_FAC_UNAVAIL:
                kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
                r = RESUME_GUEST;
                break;
        default:
                kvmppc_dump_regs(vcpu);
                printk(KERN_EMERG "trap=0x%x | pc=0x%lx | msr=0x%llx\n",
                        vcpu->arch.trap, kvmppc_get_pc(vcpu),
                        vcpu->arch.shregs.msr);
                run->hw.hardware_exit_reason = vcpu->arch.trap;
                r = RESUME_HOST;
                break;
        }

        return r;
}

static int kvm_arch_vcpu_ioctl_get_sregs_hv(struct kvm_vcpu *vcpu,
                                            struct kvm_sregs *sregs)
{
        int i;

        memset(sregs, 0, sizeof(struct kvm_sregs));
        sregs->pvr = vcpu->arch.pvr;
        for (i = 0; i < vcpu->arch.slb_max; i++) {
                sregs->u.s.ppc64.slb[i].slbe = vcpu->arch.slb[i].orige;
                sregs->u.s.ppc64.slb[i].slbv = vcpu->arch.slb[i].origv;
        }

        return 0;
}

static int kvm_arch_vcpu_ioctl_set_sregs_hv(struct kvm_vcpu *vcpu,
                                            struct kvm_sregs *sregs)
{
        int i, j;

        /* Only accept the same PVR as the host's, since we can't spoof it */
        if (sregs->pvr != vcpu->arch.pvr)
                return -EINVAL;

        j = 0;
        for (i = 0; i < vcpu->arch.slb_nr; i++) {
                if (sregs->u.s.ppc64.slb[i].slbe & SLB_ESID_V) {
                        vcpu->arch.slb[j].orige = sregs->u.s.ppc64.slb[i].slbe;
                        vcpu->arch.slb[j].origv = sregs->u.s.ppc64.slb[i].slbv;
                        ++j;
                }
        }
        vcpu->arch.slb_max = j;

        return 0;
}

static void kvmppc_set_lpcr(struct kvm_vcpu *vcpu, u64 new_lpcr,
                bool preserve_top32)
{
        struct kvm *kvm = vcpu->kvm;
        struct kvmppc_vcore *vc = vcpu->arch.vcore;
        u64 mask;

        mutex_lock(&kvm->lock);
        spin_lock(&vc->lock);
        /*
         * If ILE (interrupt little-endian) has changed, update the
         * MSR_LE bit in the intr_msr for each vcpu in this vcore.
         */
        if ((new_lpcr & LPCR_ILE) != (vc->lpcr & LPCR_ILE)) {
                struct kvm_vcpu *vcpu;
                int i;

                kvm_for_each_vcpu(i, vcpu, kvm) {
                        if (vcpu->arch.vcore != vc)
                                continue;
                        if (new_lpcr & LPCR_ILE)
                                vcpu->arch.intr_msr |= MSR_LE;
                        else
                                vcpu->arch.intr_msr &= ~MSR_LE;
                }
        }

        /*
         * Userspace can only modify DPFD (default prefetch depth),
         * ILE (interrupt little-endian) and TC (translation control).
         * On POWER8 userspace can also modify AIL (alt. interrupt loc.)
         */
        mask = LPCR_DPFD | LPCR_ILE | LPCR_TC;
        if (cpu_has_feature(CPU_FTR_ARCH_207S))
                mask |= LPCR_AIL;

        /* Broken 32-bit version of LPCR must not clear top bits */
        if (preserve_top32)
                mask &= 0xFFFFFFFF;
        vc->lpcr = (vc->lpcr & ~mask) | (new_lpcr & mask);
        spin_unlock(&vc->lock);
        mutex_unlock(&kvm->lock);
}

static int kvmppc_get_one_reg_hv(struct kvm_vcpu *vcpu, u64 id,
                                 union kvmppc_one_reg *val)
{
        int r = 0;
        long int i;

        switch (id) {
        case KVM_REG_PPC_DEBUG_INST:
                *val = get_reg_val(id, KVMPPC_INST_SW_BREAKPOINT);
                break;
        case KVM_REG_PPC_HIOR:
                *val = get_reg_val(id, 0);
                break;
        case KVM_REG_PPC_DABR:
                *val = get_reg_val(id, vcpu->arch.dabr);
                break;
        case KVM_REG_PPC_DABRX:
                *val = get_reg_val(id, vcpu->arch.dabrx);
                break;
        case KVM_REG_PPC_DSCR:
                *val = get_reg_val(id, vcpu->arch.dscr);
                break;
        case KVM_REG_PPC_PURR:
                *val = get_reg_val(id, vcpu->arch.purr);
                break;
        case KVM_REG_PPC_SPURR:
                *val = get_reg_val(id, vcpu->arch.spurr);
                break;
        case KVM_REG_PPC_AMR:
                *val = get_reg_val(id, vcpu->arch.amr);
                break;
        case KVM_REG_PPC_UAMOR:
                *val = get_reg_val(id, vcpu->arch.uamor);
                break;
        case KVM_REG_PPC_MMCR0 ... KVM_REG_PPC_MMCRS:
                i = id - KVM_REG_PPC_MMCR0;
                *val = get_reg_val(id, vcpu->arch.mmcr[i]);
                break;
        case KVM_REG_PPC_PMC1 ... KVM_REG_PPC_PMC8:
                i = id - KVM_REG_PPC_PMC1;
                *val = get_reg_val(id, vcpu->arch.pmc[i]);
                break;
        case KVM_REG_PPC_SPMC1 ... KVM_REG_PPC_SPMC2:
                i = id - KVM_REG_PPC_SPMC1;
                *val = get_reg_val(id, vcpu->arch.spmc[i]);
                break;
        case KVM_REG_PPC_SIAR:
                *val = get_reg_val(id, vcpu->arch.siar);
                break;
        case KVM_REG_PPC_SDAR:
                *val = get_reg_val(id, vcpu->arch.sdar);
                break;
        case KVM_REG_PPC_SIER:
                *val = get_reg_val(id, vcpu->arch.sier);
                break;
        case KVM_REG_PPC_IAMR:
                *val = get_reg_val(id, vcpu->arch.iamr);
                break;
        case KVM_REG_PPC_PSPB:
                *val = get_reg_val(id, vcpu->arch.pspb);
                break;
        case KVM_REG_PPC_DPDES:
                *val = get_reg_val(id, vcpu->arch.vcore->dpdes);
                break;
        case KVM_REG_PPC_DAWR:
                *val = get_reg_val(id, vcpu->arch.dawr);
                break;
        case KVM_REG_PPC_DAWRX:
                *val = get_reg_val(id, vcpu->arch.dawrx);
                break;
        case KVM_REG_PPC_CIABR:
                *val = get_reg_val(id, vcpu->arch.ciabr);
                break;
        case KVM_REG_PPC_CSIGR:
                *val = get_reg_val(id, vcpu->arch.csigr);
                break;
        case KVM_REG_PPC_TACR:
                *val = get_reg_val(id, vcpu->arch.tacr);
                break;
        case KVM_REG_PPC_TCSCR:
                *val = get_reg_val(id, vcpu->arch.tcscr);
                break;
        case KVM_REG_PPC_PID:
                *val = get_reg_val(id, vcpu->arch.pid);
                break;
        case KVM_REG_PPC_ACOP:
                *val = get_reg_val(id, vcpu->arch.acop);
                break;
        case KVM_REG_PPC_WORT:
                *val = get_reg_val(id, vcpu->arch.wort);
                break;
        case KVM_REG_PPC_VPA_ADDR:
                spin_lock(&vcpu->arch.vpa_update_lock);
                *val = get_reg_val(id, vcpu->arch.vpa.next_gpa);
                spin_unlock(&vcpu->arch.vpa_update_lock);
                break;
        case KVM_REG_PPC_VPA_SLB:
                spin_lock(&vcpu->arch.vpa_update_lock);
                val->vpaval.addr = vcpu->arch.slb_shadow.next_gpa;
                val->vpaval.length = vcpu->arch.slb_shadow.len;
                spin_unlock(&vcpu->arch.vpa_update_lock);
                break;
        case KVM_REG_PPC_VPA_DTL:
                spin_lock(&vcpu->arch.vpa_update_lock);
                val->vpaval.addr = vcpu->arch.dtl.next_gpa;
                val->vpaval.length = vcpu->arch.dtl.len;
                spin_unlock(&vcpu->arch.vpa_update_lock);
                break;
        case KVM_REG_PPC_TB_OFFSET:
                *val = get_reg_val(id, vcpu->arch.vcore->tb_offset);
                break;
        case KVM_REG_PPC_LPCR:
        case KVM_REG_PPC_LPCR_64:
                *val = get_reg_val(id, vcpu->arch.vcore->lpcr);
                break;
        case KVM_REG_PPC_PPR:
                *val = get_reg_val(id, vcpu->arch.ppr);
                break;
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
        case KVM_REG_PPC_TFHAR:
                *val = get_reg_val(id, vcpu->arch.tfhar);
                break;
        case KVM_REG_PPC_TFIAR:
                *val = get_reg_val(id, vcpu->arch.tfiar);
                break;
        case KVM_REG_PPC_TEXASR:
                *val = get_reg_val(id, vcpu->arch.texasr);
                break;
        case KVM_REG_PPC_TM_GPR0 ... KVM_REG_PPC_TM_GPR31:
                i = id - KVM_REG_PPC_TM_GPR0;
                *val = get_reg_val(id, vcpu->arch.gpr_tm[i]);
                break;
        case KVM_REG_PPC_TM_VSR0 ... KVM_REG_PPC_TM_VSR63:
        {
                int j;
                i = id - KVM_REG_PPC_TM_VSR0;
                if (i < 32)
                        for (j = 0; j < TS_FPRWIDTH; j++)
                                val->vsxval[j] = vcpu->arch.fp_tm.fpr[i][j];
                else {
                        if (cpu_has_feature(CPU_FTR_ALTIVEC))
                                val->vval = vcpu->arch.vr_tm.vr[i-32];
                        else
                                r = -ENXIO;
                }
                break;
        }
        case KVM_REG_PPC_TM_CR:
                *val = get_reg_val(id, vcpu->arch.cr_tm);
                break;
        case KVM_REG_PPC_TM_XER:
                *val = get_reg_val(id, vcpu->arch.xer_tm);
                break;
        case KVM_REG_PPC_TM_LR:
                *val = get_reg_val(id, vcpu->arch.lr_tm);
                break;
        case KVM_REG_PPC_TM_CTR:
                *val = get_reg_val(id, vcpu->arch.ctr_tm);
                break;
        case KVM_REG_PPC_TM_FPSCR:
                *val = get_reg_val(id, vcpu->arch.fp_tm.fpscr);
                break;
        case KVM_REG_PPC_TM_AMR:
                *val = get_reg_val(id, vcpu->arch.amr_tm);
                break;
        case KVM_REG_PPC_TM_PPR:
                *val = get_reg_val(id, vcpu->arch.ppr_tm);
                break;
        case KVM_REG_PPC_TM_VRSAVE:
                *val = get_reg_val(id, vcpu->arch.vrsave_tm);
                break;
        case KVM_REG_PPC_TM_VSCR:
                if (cpu_has_feature(CPU_FTR_ALTIVEC))
                        *val = get_reg_val(id, vcpu->arch.vr_tm.vscr.u[3]);
                else
                        r = -ENXIO;
                break;
        case KVM_REG_PPC_TM_DSCR:
                *val = get_reg_val(id, vcpu->arch.dscr_tm);
                break;
        case KVM_REG_PPC_TM_TAR:
                *val = get_reg_val(id, vcpu->arch.tar_tm);
                break;
#endif
        case KVM_REG_PPC_ARCH_COMPAT:
                *val = get_reg_val(id, vcpu->arch.vcore->arch_compat);
                break;
        default:
                r = -EINVAL;
                break;
        }

        return r;
}

static int kvmppc_set_one_reg_hv(struct kvm_vcpu *vcpu, u64 id,
                                 union kvmppc_one_reg *val)
{
        int r = 0;
        long int i;
        unsigned long addr, len;

        switch (id) {
        case KVM_REG_PPC_HIOR:
                /* Only allow this to be set to zero */
                if (set_reg_val(id, *val))
                        r = -EINVAL;
                break;
        case KVM_REG_PPC_DABR:
                vcpu->arch.dabr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_DABRX:
                vcpu->arch.dabrx = set_reg_val(id, *val) & ~DABRX_HYP;
                break;
        case KVM_REG_PPC_DSCR:
                vcpu->arch.dscr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_PURR:
                vcpu->arch.purr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_SPURR:
                vcpu->arch.spurr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_AMR:
                vcpu->arch.amr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_UAMOR:
                vcpu->arch.uamor = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_MMCR0 ... KVM_REG_PPC_MMCRS:
                i = id - KVM_REG_PPC_MMCR0;
                vcpu->arch.mmcr[i] = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_PMC1 ... KVM_REG_PPC_PMC8:
                i = id - KVM_REG_PPC_PMC1;
                vcpu->arch.pmc[i] = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_SPMC1 ... KVM_REG_PPC_SPMC2:
                i = id - KVM_REG_PPC_SPMC1;
                vcpu->arch.spmc[i] = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_SIAR:
                vcpu->arch.siar = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_SDAR:
                vcpu->arch.sdar = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_SIER:
                vcpu->arch.sier = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_IAMR:
                vcpu->arch.iamr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_PSPB:
                vcpu->arch.pspb = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_DPDES:
                vcpu->arch.vcore->dpdes = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_DAWR:
                vcpu->arch.dawr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_DAWRX:
                vcpu->arch.dawrx = set_reg_val(id, *val) & ~DAWRX_HYP;
                break;
        case KVM_REG_PPC_CIABR:
                vcpu->arch.ciabr = set_reg_val(id, *val);
                /* Don't allow setting breakpoints in hypervisor code */
                if ((vcpu->arch.ciabr & CIABR_PRIV) == CIABR_PRIV_HYPER)
                        vcpu->arch.ciabr &= ~CIABR_PRIV;        /* disable */
                break;
        case KVM_REG_PPC_CSIGR:
                vcpu->arch.csigr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TACR:
                vcpu->arch.tacr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TCSCR:
                vcpu->arch.tcscr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_PID:
                vcpu->arch.pid = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_ACOP:
                vcpu->arch.acop = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_WORT:
                vcpu->arch.wort = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_VPA_ADDR:
                addr = set_reg_val(id, *val);
                r = -EINVAL;
                if (!addr && (vcpu->arch.slb_shadow.next_gpa ||
                              vcpu->arch.dtl.next_gpa))
                        break;
                r = set_vpa(vcpu, &vcpu->arch.vpa, addr, sizeof(struct lppaca));
                break;
        case KVM_REG_PPC_VPA_SLB:
                addr = val->vpaval.addr;
                len = val->vpaval.length;
                r = -EINVAL;
                if (addr && !vcpu->arch.vpa.next_gpa)
                        break;
                r = set_vpa(vcpu, &vcpu->arch.slb_shadow, addr, len);
                break;
        case KVM_REG_PPC_VPA_DTL:
                addr = val->vpaval.addr;
                len = val->vpaval.length;
                r = -EINVAL;
                if (addr && (len < sizeof(struct dtl_entry) ||
                             !vcpu->arch.vpa.next_gpa))
                        break;
                len -= len % sizeof(struct dtl_entry);
                r = set_vpa(vcpu, &vcpu->arch.dtl, addr, len);
                break;
        case KVM_REG_PPC_TB_OFFSET:
                /* round up to multiple of 2^24 */
                vcpu->arch.vcore->tb_offset =
                        ALIGN(set_reg_val(id, *val), 1UL << 24);
                break;
        case KVM_REG_PPC_LPCR:
                kvmppc_set_lpcr(vcpu, set_reg_val(id, *val), true);
                break;
        case KVM_REG_PPC_LPCR_64:
                kvmppc_set_lpcr(vcpu, set_reg_val(id, *val), false);
                break;
        case KVM_REG_PPC_PPR:
                vcpu->arch.ppr = set_reg_val(id, *val);
                break;
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
        case KVM_REG_PPC_TFHAR:
                vcpu->arch.tfhar = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TFIAR:
                vcpu->arch.tfiar = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TEXASR:
                vcpu->arch.texasr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TM_GPR0 ... KVM_REG_PPC_TM_GPR31:
                i = id - KVM_REG_PPC_TM_GPR0;
                vcpu->arch.gpr_tm[i] = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TM_VSR0 ... KVM_REG_PPC_TM_VSR63:
        {
                int j;
                i = id - KVM_REG_PPC_TM_VSR0;
                if (i < 32)
                        for (j = 0; j < TS_FPRWIDTH; j++)
                                vcpu->arch.fp_tm.fpr[i][j] = val->vsxval[j];
                else
                        if (cpu_has_feature(CPU_FTR_ALTIVEC))
                                vcpu->arch.vr_tm.vr[i-32] = val->vval;
                        else
                                r = -ENXIO;
                break;
        }
        case KVM_REG_PPC_TM_CR:
                vcpu->arch.cr_tm = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TM_XER:
                vcpu->arch.xer_tm = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TM_LR:
                vcpu->arch.lr_tm = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TM_CTR:
                vcpu->arch.ctr_tm = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TM_FPSCR:
                vcpu->arch.fp_tm.fpscr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TM_AMR:
                vcpu->arch.amr_tm = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TM_PPR:
                vcpu->arch.ppr_tm = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TM_VRSAVE:
                vcpu->arch.vrsave_tm = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TM_VSCR:
                if (cpu_has_feature(CPU_FTR_ALTIVEC))
                        vcpu->arch.vr.vscr.u[3] = set_reg_val(id, *val);
                else
                        r = - ENXIO;
                break;
        case KVM_REG_PPC_TM_DSCR:
                vcpu->arch.dscr_tm = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_TM_TAR:
                vcpu->arch.tar_tm = set_reg_val(id, *val);
                break;
#endif
        case KVM_REG_PPC_ARCH_COMPAT:
                r = kvmppc_set_arch_compat(vcpu, set_reg_val(id, *val));
                break;
        default:
                r = -EINVAL;
                break;
        }

        return r;
}

static struct kvmppc_vcore *kvmppc_vcore_create(struct kvm *kvm, int core)
{
        struct kvmppc_vcore *vcore;

        vcore = kzalloc(sizeof(struct kvmppc_vcore), GFP_KERNEL);

        if (vcore == NULL)
                return NULL;

        INIT_LIST_HEAD(&vcore->runnable_threads);
        spin_lock_init(&vcore->lock);
        spin_lock_init(&vcore->stoltb_lock);
        init_waitqueue_head(&vcore->wq);
        vcore->preempt_tb = TB_NIL;
        vcore->lpcr = kvm->arch.lpcr;
        vcore->first_vcpuid = core * threads_per_subcore;
        vcore->kvm = kvm;
        INIT_LIST_HEAD(&vcore->preempt_list);

        return vcore;
}

#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
static struct debugfs_timings_element {
        const char *name;
        size_t offset;
} timings[] = {
        {"rm_entry",    offsetof(struct kvm_vcpu, arch.rm_entry)},
        {"rm_intr",     offsetof(struct kvm_vcpu, arch.rm_intr)},
        {"rm_exit",     offsetof(struct kvm_vcpu, arch.rm_exit)},
        {"guest",       offsetof(struct kvm_vcpu, arch.guest_time)},
        {"cede",        offsetof(struct kvm_vcpu, arch.cede_time)},
};

#define N_TIMINGS       (sizeof(timings) / sizeof(timings[0]))

struct debugfs_timings_state {
        struct kvm_vcpu *vcpu;
        unsigned int    buflen;
        char            buf[N_TIMINGS * 100];
};

static int debugfs_timings_open(struct inode *inode, struct file *file)
{
        struct kvm_vcpu *vcpu = inode->i_private;
        struct debugfs_timings_state *p;

        p = kzalloc(sizeof(*p), GFP_KERNEL);
        if (!p)
                return -ENOMEM;

        kvm_get_kvm(vcpu->kvm);
        p->vcpu = vcpu;
        file->private_data = p;

        return nonseekable_open(inode, file);
}

static int debugfs_timings_release(struct inode *inode, struct file *file)
{
        struct debugfs_timings_state *p = file->private_data;

        kvm_put_kvm(p->vcpu->kvm);
        kfree(p);
        return 0;
}

static ssize_t debugfs_timings_read(struct file *file, char __user *buf,
                                    size_t len, loff_t *ppos)
{
        struct debugfs_timings_state *p = file->private_data;
        struct kvm_vcpu *vcpu = p->vcpu;
        char *s, *buf_end;
        struct kvmhv_tb_accumulator tb;
        u64 count;
        loff_t pos;
        ssize_t n;
        int i, loops;
        bool ok;

        if (!p->buflen) {
                s = p->buf;
                buf_end = s + sizeof(p->buf);
                for (i = 0; i < N_TIMINGS; ++i) {
                        struct kvmhv_tb_accumulator *acc;

                        acc = (struct kvmhv_tb_accumulator *)
                                ((unsigned long)vcpu + timings[i].offset);
                        ok = false;
                        for (loops = 0; loops < 1000; ++loops) {
                                count = acc->seqcount;
                                if (!(count & 1)) {
                                        smp_rmb();
                                        tb = *acc;
                                        smp_rmb();
                                        if (count == acc->seqcount) {
                                                ok = true;
                                                break;
                                        }
                                }
                                udelay(1);
                        }
                        if (!ok)
                                snprintf(s, buf_end - s, "%s: stuck\n",
                                        timings[i].name);
                        else
                                snprintf(s, buf_end - s,
                                        "%s: %llu %llu %llu %llu\n",
                                        timings[i].name, count / 2,
                                        tb_to_ns(tb.tb_total),
                                        tb_to_ns(tb.tb_min),
                                        tb_to_ns(tb.tb_max));
                        s += strlen(s);
                }
                p->buflen = s - p->buf;
        }

        pos = *ppos;
        if (pos >= p->buflen)
                return 0;
        if (len > p->buflen - pos)
                len = p->buflen - pos;
        n = copy_to_user(buf, p->buf + pos, len);
        if (n) {
                if (n == len)
                        return -EFAULT;
                len -= n;
        }
        *ppos = pos + len;
        return len;
}

static ssize_t debugfs_timings_write(struct file *file, const char __user *buf,
                                     size_t len, loff_t *ppos)
{
        return -EACCES;
}

static const struct file_operations debugfs_timings_ops = {
        .owner   = THIS_MODULE,
        .open    = debugfs_timings_open,
        .release = debugfs_timings_release,
        .read    = debugfs_timings_read,
        .write   = debugfs_timings_write,
        .llseek  = generic_file_llseek,
};

/* Create a debugfs directory for the vcpu */
static void debugfs_vcpu_init(struct kvm_vcpu *vcpu, unsigned int id)
{
        char buf[16];
        struct kvm *kvm = vcpu->kvm;

        snprintf(buf, sizeof(buf), "vcpu%u", id);
        if (IS_ERR_OR_NULL(kvm->arch.debugfs_dir))
                return;
        vcpu->arch.debugfs_dir = debugfs_create_dir(buf, kvm->arch.debugfs_dir);
        if (IS_ERR_OR_NULL(vcpu->arch.debugfs_dir))
                return;
        vcpu->arch.debugfs_timings =
                debugfs_create_file("timings", 0444, vcpu->arch.debugfs_dir,
                                    vcpu, &debugfs_timings_ops);
}

#else /* CONFIG_KVM_BOOK3S_HV_EXIT_TIMING */
static void debugfs_vcpu_init(struct kvm_vcpu *vcpu, unsigned int id)
{
}
#endif /* CONFIG_KVM_BOOK3S_HV_EXIT_TIMING */

static struct kvm_vcpu *kvmppc_core_vcpu_create_hv(struct kvm *kvm,
                                                   unsigned int id)
{
        struct kvm_vcpu *vcpu;
        int err = -EINVAL;
        int core;
        struct kvmppc_vcore *vcore;

        core = id / threads_per_subcore;
        if (core >= KVM_MAX_VCORES)
                goto out;

        err = -ENOMEM;
        vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
        if (!vcpu)
                goto out;

        err = kvm_vcpu_init(vcpu, kvm, id);
        if (err)
                goto free_vcpu;

        vcpu->arch.shared = &vcpu->arch.shregs;
#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
        /*
         * The shared struct is never shared on HV,
         * so we can always use host endianness
         */
#ifdef __BIG_ENDIAN__
        vcpu->arch.shared_big_endian = true;
#else
        vcpu->arch.shared_big_endian = false;
#endif
#endif
        vcpu->arch.mmcr[0] = MMCR0_FC;
        vcpu->arch.ctrl = CTRL_RUNLATCH;
        /* default to host PVR, since we can't spoof it */
        kvmppc_set_pvr_hv(vcpu, mfspr(SPRN_PVR));
        spin_lock_init(&vcpu->arch.vpa_update_lock);
        spin_lock_init(&vcpu->arch.tbacct_lock);
        vcpu->arch.busy_preempt = TB_NIL;
        vcpu->arch.intr_msr = MSR_SF | MSR_ME;

        kvmppc_mmu_book3s_hv_init(vcpu);

        vcpu->arch.state = KVMPPC_VCPU_NOTREADY;

        init_waitqueue_head(&vcpu->arch.cpu_run);

        mutex_lock(&kvm->lock);
        vcore = kvm->arch.vcores[core];
        if (!vcore) {
                vcore = kvmppc_vcore_create(kvm, core);
                kvm->arch.vcores[core] = vcore;
                kvm->arch.online_vcores++;
        }
        mutex_unlock(&kvm->lock);

        if (!vcore)
                goto uninit_vcpu;

        spin_lock(&vcore->lock);
        ++vcore->num_threads;
        spin_unlock(&vcore->lock);
        vcpu->arch.vcore = vcore;
        vcpu->arch.ptid = vcpu->vcpu_id - vcore->first_vcpuid;
        vcpu->arch.thread_cpu = -1;

        vcpu->arch.cpu_type = KVM_CPU_3S_64;
        kvmppc_sanity_check(vcpu);

        debugfs_vcpu_init(vcpu, id);

        return vcpu;

uninit_vcpu:
        kvm_vcpu_uninit(vcpu);
free_vcpu:
        kmem_cache_free(kvm_vcpu_cache, vcpu);
out:
        return ERR_PTR(err);
}

static void unpin_vpa(struct kvm *kvm, struct kvmppc_vpa *vpa)
{
        if (vpa->pinned_addr)
                kvmppc_unpin_guest_page(kvm, vpa->pinned_addr, vpa->gpa,
                                        vpa->dirty);
}

static void kvmppc_core_vcpu_free_hv(struct kvm_vcpu *vcpu)
{
        spin_lock(&vcpu->arch.vpa_update_lock);
        unpin_vpa(vcpu->kvm, &vcpu->arch.dtl);
        unpin_vpa(vcpu->kvm, &vcpu->arch.slb_shadow);
        unpin_vpa(vcpu->kvm, &vcpu->arch.vpa);
        spin_unlock(&vcpu->arch.vpa_update_lock);
        kvm_vcpu_uninit(vcpu);
        kmem_cache_free(kvm_vcpu_cache, vcpu);
}

static int kvmppc_core_check_requests_hv(struct kvm_vcpu *vcpu)
{
        /* Indicate we want to get back into the guest */
        return 1;
}

static void kvmppc_set_timer(struct kvm_vcpu *vcpu)
{
        unsigned long dec_nsec, now;

        now = get_tb();
        if (now > vcpu->arch.dec_expires) {
                /* decrementer has already gone negative */
                kvmppc_core_queue_dec(vcpu);
                kvmppc_core_prepare_to_enter(vcpu);
                return;
        }
        dec_nsec = (vcpu->arch.dec_expires - now) * NSEC_PER_SEC
                   / tb_ticks_per_sec;
        hrtimer_start(&vcpu->arch.dec_timer, ktime_set(0, dec_nsec),
                      HRTIMER_MODE_REL);
        vcpu->arch.timer_running = 1;
}

static void kvmppc_end_cede(struct kvm_vcpu *vcpu)
{
        vcpu->arch.ceded = 0;
        if (vcpu->arch.timer_running) {
                hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
                vcpu->arch.timer_running = 0;
        }
}

extern void __kvmppc_vcore_entry(void);

static void kvmppc_remove_runnable(struct kvmppc_vcore *vc,
                                   struct kvm_vcpu *vcpu)
{
        u64 now;

        if (vcpu->arch.state != KVMPPC_VCPU_RUNNABLE)
                return;
        spin_lock_irq(&vcpu->arch.tbacct_lock);
        now = mftb();
        vcpu->arch.busy_stolen += vcore_stolen_time(vc, now) -
                vcpu->arch.stolen_logged;
        vcpu->arch.busy_preempt = now;
        vcpu->arch.state = KVMPPC_VCPU_BUSY_IN_HOST;
        spin_unlock_irq(&vcpu->arch.tbacct_lock);
        --vc->n_runnable;
        list_del(&vcpu->arch.run_list);
}

static int kvmppc_grab_hwthread(int cpu)
{
        struct paca_struct *tpaca;
        long timeout = 10000;

        tpaca = &paca[cpu];

        /* Ensure the thread won't go into the kernel if it wakes */
        tpaca->kvm_hstate.kvm_vcpu = NULL;
        tpaca->kvm_hstate.kvm_vcore = NULL;
        tpaca->kvm_hstate.napping = 0;
        smp_wmb();
        tpaca->kvm_hstate.hwthread_req = 1;

        /*
         * If the thread is already executing in the kernel (e.g. handling
         * a stray interrupt), wait for it to get back to nap mode.
         * The smp_mb() is to ensure that our setting of hwthread_req
         * is visible before we look at hwthread_state, so if this
         * races with the code at system_reset_pSeries and the thread
         * misses our setting of hwthread_req, we are sure to see its
         * setting of hwthread_state, and vice versa.
         */
        smp_mb();
        while (tpaca->kvm_hstate.hwthread_state == KVM_HWTHREAD_IN_KERNEL) {
                if (--timeout <= 0) {
                        pr_err("KVM: couldn't grab cpu %d\n", cpu);
                        return -EBUSY;
                }
                udelay(1);
        }
        return 0;
}

static void kvmppc_release_hwthread(int cpu)
{
        struct paca_struct *tpaca;

        tpaca = &paca[cpu];
        tpaca->kvm_hstate.hwthread_req = 0;
        tpaca->kvm_hstate.kvm_vcpu = NULL;
        tpaca->kvm_hstate.kvm_vcore = NULL;
        tpaca->kvm_hstate.kvm_split_mode = NULL;
}

static void kvmppc_start_thread(struct kvm_vcpu *vcpu, struct kvmppc_vcore *vc)
{
        int cpu;
        struct paca_struct *tpaca;
        struct kvmppc_vcore *mvc = vc->master_vcore;

        cpu = vc->pcpu;
        if (vcpu) {
                if (vcpu->arch.timer_running) {
                        hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
                        vcpu->arch.timer_running = 0;
                }
                cpu += vcpu->arch.ptid;
                vcpu->cpu = mvc->pcpu;
                vcpu->arch.thread_cpu = cpu;
        }
        tpaca = &paca[cpu];
        tpaca->kvm_hstate.kvm_vcpu = vcpu;
        tpaca->kvm_hstate.ptid = cpu - mvc->pcpu;
        /* Order stores to hstate.kvm_vcpu etc. before store to kvm_vcore */
        smp_wmb();
        tpaca->kvm_hstate.kvm_vcore = mvc;
        if (cpu != smp_processor_id())
                kvmppc_ipi_thread(cpu);
}

static void kvmppc_wait_for_nap(void)
{
        int cpu = smp_processor_id();
        int i, loops;

        for (loops = 0; loops < 1000000; ++loops) {
                /*
                 * Check if all threads are finished.
                 * We set the vcore pointer when starting a thread
                 * and the thread clears it when finished, so we look
                 * for any threads that still have a non-NULL vcore ptr.
                 */
                for (i = 1; i < threads_per_subcore; ++i)
                        if (paca[cpu + i].kvm_hstate.kvm_vcore)
                                break;
                if (i == threads_per_subcore) {
                        HMT_medium();
                        return;
                }
                HMT_low();
        }
        HMT_medium();
        for (i = 1; i < threads_per_subcore; ++i)
                if (paca[cpu + i].kvm_hstate.kvm_vcore)
                        pr_err("KVM: CPU %d seems to be stuck\n", cpu + i);
}

/*
 * Check that we are on thread 0 and that any other threads in
 * this core are off-line.  Then grab the threads so they can't
 * enter the kernel.
 */
static int on_primary_thread(void)
{
        int cpu = smp_processor_id();
        int thr;

        /* Are we on a primary subcore? */
        if (cpu_thread_in_subcore(cpu))
                return 0;

        thr = 0;
        while (++thr < threads_per_subcore)
                if (cpu_online(cpu + thr))
                        return 0;

        /* Grab all hw threads so they can't go into the kernel */
        for (thr = 1; thr < threads_per_subcore; ++thr) {
                if (kvmppc_grab_hwthread(cpu + thr)) {
                        /* Couldn't grab one; let the others go */
                        do {
                                kvmppc_release_hwthread(cpu + thr);
                        } while (--thr > 0);
                        return 0;
                }
        }
        return 1;
}

/*
 * A list of virtual cores for each physical CPU.
 * These are vcores that could run but their runner VCPU tasks are
 * (or may be) preempted.
 */
struct preempted_vcore_list {
        struct list_head        list;
        spinlock_t              lock;
};

static DEFINE_PER_CPU(struct preempted_vcore_list, preempted_vcores);

static void init_vcore_lists(void)
{
        int cpu;

        for_each_possible_cpu(cpu) {
                struct preempted_vcore_list *lp = &per_cpu(preempted_vcores, cpu);
                spin_lock_init(&lp->lock);
                INIT_LIST_HEAD(&lp->list);
        }
}

static void kvmppc_vcore_preempt(struct kvmppc_vcore *vc)
{
        struct preempted_vcore_list *lp = this_cpu_ptr(&preempted_vcores);

        vc->vcore_state = VCORE_PREEMPT;
        vc->pcpu = smp_processor_id();
        if (vc->num_threads < threads_per_subcore) {
                spin_lock(&lp->lock);
                list_add_tail(&vc->preempt_list, &lp->list);
                spin_unlock(&lp->lock);
        }

        /* Start accumulating stolen time */
        kvmppc_core_start_stolen(vc);
}

static void kvmppc_vcore_end_preempt(struct kvmppc_vcore *vc)
{
        struct preempted_vcore_list *lp;

        kvmppc_core_end_stolen(vc);
        if (!list_empty(&vc->preempt_list)) {
                lp = &per_cpu(preempted_vcores, vc->pcpu);
                spin_lock(&lp->lock);
                list_del_init(&vc->preempt_list);
                spin_unlock(&lp->lock);
        }
        vc->vcore_state = VCORE_INACTIVE;
}

/*
 * This stores information about the virtual cores currently
 * assigned to a physical core.
 */
struct core_info {
        int             n_subcores;
        int             max_subcore_threads;
        int             total_threads;
        int             subcore_threads[MAX_SUBCORES];
        struct kvm      *subcore_vm[MAX_SUBCORES];
        struct list_head vcs[MAX_SUBCORES];
};

/*
 * This mapping means subcores 0 and 1 can use threads 0-3 and 4-7
 * respectively in 2-way micro-threading (split-core) mode.
 */
static int subcore_thread_map[MAX_SUBCORES] = { 0, 4, 2, 6 };

static void init_core_info(struct core_info *cip, struct kvmppc_vcore *vc)
{
        int sub;

        memset(cip, 0, sizeof(*cip));
        cip->n_subcores = 1;
        cip->max_subcore_threads = vc->num_threads;
        cip->total_threads = vc->num_threads;
        cip->subcore_threads[0] = vc->num_threads;
        cip->subcore_vm[0] = vc->kvm;
        for (sub = 0; sub < MAX_SUBCORES; ++sub)
                INIT_LIST_HEAD(&cip->vcs[sub]);
        list_add_tail(&vc->preempt_list, &cip->vcs[0]);
}

static bool subcore_config_ok(int n_subcores, int n_threads)
{
        /* Can only dynamically split if unsplit to begin with */
        if (n_subcores > 1 && threads_per_subcore < MAX_SMT_THREADS)
                return false;
        if (n_subcores > MAX_SUBCORES)
                return false;
        if (n_subcores > 1) {
                if (!(dynamic_mt_modes & 2))
                        n_subcores = 4;
                if (n_subcores > 2 && !(dynamic_mt_modes & 4))
                        return false;
        }

        return n_subcores * roundup_pow_of_two(n_threads) <= MAX_SMT_THREADS;
}

static void init_master_vcore(struct kvmppc_vcore *vc)
{
        vc->master_vcore = vc;
        vc->entry_exit_map = 0;
        vc->in_guest = 0;
        vc->napping_threads = 0;
        vc->conferring_threads = 0;
}

/*
 * See if the existing subcores can be split into 3 (or fewer) subcores
 * of at most two threads each, so we can fit in another vcore.  This
 * assumes there are at most two subcores and at most 6 threads in total.
 */
static bool can_split_piggybacked_subcores(struct core_info *cip)
{
        int sub, new_sub;
        int large_sub = -1;
        int thr;
        int n_subcores = cip->n_subcores;
        struct kvmppc_vcore *vc, *vcnext;
        struct kvmppc_vcore *master_vc = NULL;

        for (sub = 0; sub < cip->n_subcores; ++sub) {
                if (cip->subcore_threads[sub] <= 2)
                        continue;
                if (large_sub >= 0)
                        return false;
                large_sub = sub;
                vc = list_first_entry(&cip->vcs[sub], struct kvmppc_vcore,
                                      preempt_list);
                if (vc->num_threads > 2)
                        return false;
                n_subcores += (cip->subcore_threads[sub] - 1) >> 1;
        }
        if (large_sub < 0 || !subcore_config_ok(n_subcores + 1, 2))
                return false;

        /*
         * Seems feasible, so go through and move vcores to new subcores.
         * Note that when we have two or more vcores in one subcore,
         * all those vcores must have only one thread each.
         */
        new_sub = cip->n_subcores;
        thr = 0;
        sub = large_sub;
        list_for_each_entry_safe(vc, vcnext, &cip->vcs[sub], preempt_list) {
                if (thr >= 2) {
                        list_del(&vc->preempt_list);
                        list_add_tail(&vc->preempt_list, &cip->vcs[new_sub]);
                        /* vc->num_threads must be 1 */
                        if (++cip->subcore_threads[new_sub] == 1) {
                                cip->subcore_vm[new_sub] = vc->kvm;
                                init_master_vcore(vc);
                                master_vc = vc;
                                ++cip->n_subcores;
                        } else {
                                vc->master_vcore = master_vc;
                                ++new_sub;
                        }
                }
                thr += vc->num_threads;
        }
        cip->subcore_threads[large_sub] = 2;
        cip->max_subcore_threads = 2;

        return true;
}

static bool can_dynamic_split(struct kvmppc_vcore *vc, struct core_info *cip)
{
        int n_threads = vc->num_threads;
        int sub;

        if (!cpu_has_feature(CPU_FTR_ARCH_207S))
                return false;

        if (n_threads < cip->max_subcore_threads)
                n_threads = cip->max_subcore_threads;
        if (subcore_config_ok(cip->n_subcores + 1, n_threads)) {
                cip->max_subcore_threads = n_threads;
        } else if (cip->n_subcores <= 2 && cip->total_threads <= 6 &&
                   vc->num_threads <= 2) {
                /*
                 * We may be able to fit another subcore in by
                 * splitting an existing subcore with 3 or 4
                 * threads into two 2-thread subcores, or one
                 * with 5 or 6 threads into three subcores.
                 * We can only do this if those subcores have
                 * piggybacked virtual cores.
                 */
                if (!can_split_piggybacked_subcores(cip))
                        return false;
        } else {
                return false;
        }

        sub = cip->n_subcores;
        ++cip->n_subcores;
        cip->total_threads += vc->num_threads;
        cip->subcore_threads[sub] = vc->num_threads;
        cip->subcore_vm[sub] = vc->kvm;
        init_master_vcore(vc);
        list_del(&vc->preempt_list);
        list_add_tail(&vc->preempt_list, &cip->vcs[sub]);

        return true;
}

static bool can_piggyback_subcore(struct kvmppc_vcore *pvc,
                                  struct core_info *cip, int sub)
{
        struct kvmppc_vcore *vc;
        int n_thr;

        vc = list_first_entry(&cip->vcs[sub], struct kvmppc_vcore,
                              preempt_list);

        /* require same VM and same per-core reg values */
        if (pvc->kvm != vc->kvm ||
            pvc->tb_offset != vc->tb_offset ||
            pvc->pcr != vc->pcr ||
            pvc->lpcr != vc->lpcr)
                return false;

        /* P8 guest with > 1 thread per core would see wrong TIR value */
        if (cpu_has_feature(CPU_FTR_ARCH_207S) &&
            (vc->num_threads > 1 || pvc->num_threads > 1))
                return false;

        n_thr = cip->subcore_threads[sub] + pvc->num_threads;
        if (n_thr > cip->max_subcore_threads) {
                if (!subcore_config_ok(cip->n_subcores, n_thr))
                        return false;
                cip->max_subcore_threads = n_thr;
        }

        cip->total_threads += pvc->num_threads;
        cip->subcore_threads[sub] = n_thr;
        pvc->master_vcore = vc;
        list_del(&pvc->preempt_list);
        list_add_tail(&pvc->preempt_list, &cip->vcs[sub]);

        return true;
}

/*
 * Work out whether it is possible to piggyback the execution of
 * vcore *pvc onto the execution of the other vcores described in *cip.
 */
static bool can_piggyback(struct kvmppc_vcore *pvc, struct core_info *cip,
                          int target_threads)
{
        int sub;

        if (cip->total_threads + pvc->num_threads > target_threads)
                return false;
        for (sub = 0; sub < cip->n_subcores; ++sub)
                if (cip->subcore_threads[sub] &&
                    can_piggyback_subcore(pvc, cip, sub))
                        return true;

        if (can_dynamic_split(pvc, cip))
                return true;

        return false;
}

static void prepare_threads(struct kvmppc_vcore *vc)
{
        struct kvm_vcpu *vcpu, *vnext;

        list_for_each_entry_safe(vcpu, vnext, &vc->runnable_threads,
                                 arch.run_list) {
                if (signal_pending(vcpu->arch.run_task))
                        vcpu->arch.ret = -EINTR;
                else if (vcpu->arch.vpa.update_pending ||
                         vcpu->arch.slb_shadow.update_pending ||
                         vcpu->arch.dtl.update_pending)
                        vcpu->arch.ret = RESUME_GUEST;
                else
                        continue;
                kvmppc_remove_runnable(vc, vcpu);
                wake_up(&vcpu->arch.cpu_run);
        }
}

static void collect_piggybacks(struct core_info *cip, int target_threads)
{
        struct preempted_vcore_list *lp = this_cpu_ptr(&preempted_vcores);
        struct kvmppc_vcore *pvc, *vcnext;

        spin_lock(&lp->lock);
        list_for_each_entry_safe(pvc, vcnext, &lp->list, preempt_list) {
                if (!spin_trylock(&pvc->lock))
                        continue;
                prepare_threads(pvc);
                if (!pvc->n_runnable) {
                        list_del_init(&pvc->preempt_list);
                        if (pvc->runner == NULL) {
                                pvc->vcore_state = VCORE_INACTIVE;
                                kvmppc_core_end_stolen(pvc);
                        }
                        spin_unlock(&pvc->lock);
                        continue;
                }
                if (!can_piggyback(pvc, cip, target_threads)) {
                        spin_unlock(&pvc->lock);
                        continue;
                }
                kvmppc_core_end_stolen(pvc);
                pvc->vcore_state = VCORE_PIGGYBACK;
                if (cip->total_threads >= target_threads)
                        break;
        }
        spin_unlock(&lp->lock);
}

static void post_guest_process(struct kvmppc_vcore *vc, bool is_master)
{
        int still_running = 0;
        u64 now;
        long ret;
        struct kvm_vcpu *vcpu, *vnext;

        spin_lock(&vc->lock);
        now = get_tb();
        list_for_each_entry_safe(vcpu, vnext, &vc->runnable_threads,
                                 arch.run_list) {
                /* cancel pending dec exception if dec is positive */
                if (now < vcpu->arch.dec_expires &&
                    kvmppc_core_pending_dec(vcpu))
                        kvmppc_core_dequeue_dec(vcpu);

                trace_kvm_guest_exit(vcpu);

                ret = RESUME_GUEST;
                if (vcpu->arch.trap)
                        ret = kvmppc_handle_exit_hv(vcpu->arch.kvm_run, vcpu,
                                                    vcpu->arch.run_task);

                vcpu->arch.ret = ret;
                vcpu->arch.trap = 0;

                if (is_kvmppc_resume_guest(vcpu->arch.ret)) {
                        if (vcpu->arch.pending_exceptions)
                                kvmppc_core_prepare_to_enter(vcpu);
                        if (vcpu->arch.ceded)
                                kvmppc_set_timer(vcpu);
                        else
                                ++still_running;
                } else {
                        kvmppc_remove_runnable(vc, vcpu);
                        wake_up(&vcpu->arch.cpu_run);
                }
        }
        list_del_init(&vc->preempt_list);
        if (!is_master) {
                if (still_running > 0) {
                        kvmppc_vcore_preempt(vc);
                } else if (vc->runner) {
                        vc->vcore_state = VCORE_PREEMPT;
                        kvmppc_core_start_stolen(vc);
                } else {
                        vc->vcore_state = VCORE_INACTIVE;
                }
                if (vc->n_runnable > 0 && vc->runner == NULL) {
                        /* make sure there's a candidate runner awake */
                        vcpu = list_first_entry(&vc->runnable_threads,
                                                struct kvm_vcpu, arch.run_list);
                        wake_up(&vcpu->arch.cpu_run);
                }
        }
        spin_unlock(&vc->lock);
}

/*
 * Run a set of guest threads on a physical core.
 * Called with vc->lock held.
 */
static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
{
        struct kvm_vcpu *vcpu, *vnext;
        int i;
        int srcu_idx;
        struct core_info core_info;
        struct kvmppc_vcore *pvc, *vcnext;
        struct kvm_split_mode split_info, *sip;
        int split, subcore_size, active;
        int sub;
        bool thr0_done;
        unsigned long cmd_bit, stat_bit;
        int pcpu, thr;
        int target_threads;

        /*
         * Remove from the list any threads that have a signal pending
         * or need a VPA update done
         */
        prepare_threads(vc);

        /* if the runner is no longer runnable, let the caller pick a new one */
        if (vc->runner->arch.state != KVMPPC_VCPU_RUNNABLE)
                return;

        /*
         * Initialize *vc.
         */
        init_master_vcore(vc);
        vc->preempt_tb = TB_NIL;

        /*
         * Make sure we are running on primary threads, and that secondary
         * threads are offline.  Also check if the number of threads in this
         * guest are greater than the current system threads per guest.
         */
        if ((threads_per_core > 1) &&
            ((vc->num_threads > threads_per_subcore) || !on_primary_thread())) {
                list_for_each_entry_safe(vcpu, vnext, &vc->runnable_threads,
                                         arch.run_list) {
                        vcpu->arch.ret = -EBUSY;
                        kvmppc_remove_runnable(vc, vcpu);
                        wake_up(&vcpu->arch.cpu_run);
                }
                goto out;
        }

        /*
         * See if we could run any other vcores on the physical core
         * along with this one.
         */
        init_core_info(&core_info, vc);
        pcpu = smp_processor_id();
        target_threads = threads_per_subcore;
        if (target_smt_mode && target_smt_mode < target_threads)
                target_threads = target_smt_mode;
        if (vc->num_threads < target_threads)
                collect_piggybacks(&core_info, target_threads);

        /* Decide on micro-threading (split-core) mode */
        subcore_size = threads_per_subcore;
        cmd_bit = stat_bit = 0;
        split = core_info.n_subcores;
        sip = NULL;
        if (split > 1) {
                /* threads_per_subcore must be MAX_SMT_THREADS (8) here */
                if (split == 2 && (dynamic_mt_modes & 2)) {
                        cmd_bit = HID0_POWER8_1TO2LPAR;
                        stat_bit = HID0_POWER8_2LPARMODE;
                } else {
                        split = 4;
                        cmd_bit = HID0_POWER8_1TO4LPAR;
                        stat_bit = HID0_POWER8_4LPARMODE;
                }
                subcore_size = MAX_SMT_THREADS / split;
                sip = &split_info;
                memset(&split_info, 0, sizeof(split_info));
                split_info.rpr = mfspr(SPRN_RPR);
                split_info.pmmar = mfspr(SPRN_PMMAR);
                split_info.ldbar = mfspr(SPRN_LDBAR);
                split_info.subcore_size = subcore_size;
                for (sub = 0; sub < core_info.n_subcores; ++sub)
                        split_info.master_vcs[sub] =
                                list_first_entry(&core_info.vcs[sub],
                                        struct kvmppc_vcore, preempt_list);
                /* order writes to split_info before kvm_split_mode pointer */
                smp_wmb();
        }
        pcpu = smp_processor_id();
        for (thr = 0; thr < threads_per_subcore; ++thr)
                paca[pcpu + thr].kvm_hstate.kvm_split_mode = sip;

        /* Initiate micro-threading (split-core) if required */
        if (cmd_bit) {
                unsigned long hid0 = mfspr(SPRN_HID0);

                hid0 |= cmd_bit | HID0_POWER8_DYNLPARDIS;
                mb();
                mtspr(SPRN_HID0, hid0);
                isync();
                for (;;) {
                        hid0 = mfspr(SPRN_HID0);
                        if (hid0 & stat_bit)
                                break;
                        cpu_relax();
                }
        }

        /* Start all the threads */
        active = 0;
        for (sub = 0; sub < core_info.n_subcores; ++sub) {
                thr = subcore_thread_map[sub];
                thr0_done = false;
                active |= 1 << thr;
                list_for_each_entry(pvc, &core_info.vcs[sub], preempt_list) {
                        pvc->pcpu = pcpu + thr;
                        list_for_each_entry(vcpu, &pvc->runnable_threads,
                                            arch.run_list) {
                                kvmppc_start_thread(vcpu, pvc);
                                kvmppc_create_dtl_entry(vcpu, pvc);
                                trace_kvm_guest_enter(vcpu);
                                if (!vcpu->arch.ptid)
                                        thr0_done = true;
                                active |= 1 << (thr + vcpu->arch.ptid);
                        }
                        /*
                         * We need to start the first thread of each subcore
                         * even if it doesn't have a vcpu.
                         */
                        if (pvc->master_vcore == pvc && !thr0_done)
                                kvmppc_start_thread(NULL, pvc);
                        thr += pvc->num_threads;
                }
        }

        /*
         * Ensure that split_info.do_nap is set after setting
         * the vcore pointer in the PACA of the secondaries.
         */
        smp_mb();
        if (cmd_bit)
                split_info.do_nap = 1;  /* ask secondaries to nap when done */

        /*
         * When doing micro-threading, poke the inactive threads as well.
         * This gets them to the nap instruction after kvm_do_nap,
         * which reduces the time taken to unsplit later.
         */
        if (split > 1)
                for (thr = 1; thr < threads_per_subcore; ++thr)
                        if (!(active & (1 << thr)))
                                kvmppc_ipi_thread(pcpu + thr);

        vc->vcore_state = VCORE_RUNNING;
        preempt_disable();

        trace_kvmppc_run_core(vc, 0);

        for (sub = 0; sub < core_info.n_subcores; ++sub)
                list_for_each_entry(pvc, &core_info.vcs[sub], preempt_list)
                        spin_unlock(&pvc->lock);

        kvm_guest_enter();

        srcu_idx = srcu_read_lock(&vc->kvm->srcu);

        __kvmppc_vcore_entry();

        srcu_read_unlock(&vc->kvm->srcu, srcu_idx);

        spin_lock(&vc->lock);
        /* prevent other vcpu threads from doing kvmppc_start_thread() now */
        vc->vcore_state = VCORE_EXITING;

        /* wait for secondary threads to finish writing their state to memory */
        kvmppc_wait_for_nap();

        /* Return to whole-core mode if we split the core earlier */
        if (split > 1) {
                unsigned long hid0 = mfspr(SPRN_HID0);
                unsigned long loops = 0;

                hid0 &= ~HID0_POWER8_DYNLPARDIS;
                stat_bit = HID0_POWER8_2LPARMODE | HID0_POWER8_4LPARMODE;
                mb();
                mtspr(SPRN_HID0, hid0);
                isync();
                for (;;) {
                        hid0 = mfspr(SPRN_HID0);
                        if (!(hid0 & stat_bit))
                                break;
                        cpu_relax();
                        ++loops;
                }
                split_info.do_nap = 0;
        }

        /* Let secondaries go back to the offline loop */
        for (i = 0; i < threads_per_subcore; ++i) {
                kvmppc_release_hwthread(pcpu + i);
                if (sip && sip->napped[i])
                        kvmppc_ipi_thread(pcpu + i);
        }

        spin_unlock(&vc->lock);

        /* make sure updates to secondary vcpu structs are visible now */
        smp_mb();
        kvm_guest_exit();

        for (sub = 0; sub < core_info.n_subcores; ++sub)
                list_for_each_entry_safe(pvc, vcnext, &core_info.vcs[sub],
                                         preempt_list)
                        post_guest_process(pvc, pvc == vc);

        spin_lock(&vc->lock);
        preempt_enable();

 out:
        vc->vcore_state = VCORE_INACTIVE;
        trace_kvmppc_run_core(vc, 1);
}

/*
 * Wait for some other vcpu thread to execute us, and
 * wake us up when we need to handle something in the host.
 */
static void kvmppc_wait_for_exec(struct kvmppc_vcore *vc,
                                 struct kvm_vcpu *vcpu, int wait_state)
{
        DEFINE_WAIT(wait);

        prepare_to_wait(&vcpu->arch.cpu_run, &wait, wait_state);
        if (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE) {
                spin_unlock(&vc->lock);
                schedule();
                spin_lock(&vc->lock);
        }
        finish_wait(&vcpu->arch.cpu_run, &wait);
}

/*
 * All the vcpus in this vcore are idle, so wait for a decrementer
 * or external interrupt to one of the vcpus.  vc->lock is held.
 */
static void kvmppc_vcore_blocked(struct kvmppc_vcore *vc)
{
        struct kvm_vcpu *vcpu;
        int do_sleep = 1;

        DEFINE_WAIT(wait);

        prepare_to_wait(&vc->wq, &wait, TASK_INTERRUPTIBLE);

        /*
         * Check one last time for pending exceptions and ceded state after
         * we put ourselves on the wait queue
         */
        list_for_each_entry(vcpu, &vc->runnable_threads, arch.run_list) {
                if (vcpu->arch.pending_exceptions || !vcpu->arch.ceded) {
                        do_sleep = 0;
                        break;
                }
        }

        if (!do_sleep) {
                finish_wait(&vc->wq, &wait);
                return;
        }

        vc->vcore_state = VCORE_SLEEPING;
        trace_kvmppc_vcore_blocked(vc, 0);
        spin_unlock(&vc->lock);
        schedule();
        finish_wait(&vc->wq, &wait);
        spin_lock(&vc->lock);
        vc->vcore_state = VCORE_INACTIVE;
        trace_kvmppc_vcore_blocked(vc, 1);
}

static int kvmppc_run_vcpu(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
{
        int n_ceded;
        struct kvmppc_vcore *vc;
        struct kvm_vcpu *v, *vn;

        trace_kvmppc_run_vcpu_enter(vcpu);

        kvm_run->exit_reason = 0;
        vcpu->arch.ret = RESUME_GUEST;
        vcpu->arch.trap = 0;
        kvmppc_update_vpas(vcpu);

        /*
         * Synchronize with other threads in this virtual core
         */
        vc = vcpu->arch.vcore;
        spin_lock(&vc->lock);
        vcpu->arch.ceded = 0;
        vcpu->arch.run_task = current;
        vcpu->arch.kvm_run = kvm_run;
        vcpu->arch.stolen_logged = vcore_stolen_time(vc, mftb());
        vcpu->arch.state = KVMPPC_VCPU_RUNNABLE;
        vcpu->arch.busy_preempt = TB_NIL;
        list_add_tail(&vcpu->arch.run_list, &vc->runnable_threads);
        ++vc->n_runnable;

        /*
         * This happens the first time this is called for a vcpu.
         * If the vcore is already running, we may be able to start
         * this thread straight away and have it join in.
         */
        if (!signal_pending(current)) {
                if (vc->vcore_state == VCORE_PIGGYBACK) {
                        struct kvmppc_vcore *mvc = vc->master_vcore;
                        if (spin_trylock(&mvc->lock)) {
                                if (mvc->vcore_state == VCORE_RUNNING &&
                                    !VCORE_IS_EXITING(mvc)) {
                                        kvmppc_create_dtl_entry(vcpu, vc);
                                        kvmppc_start_thread(vcpu, vc);
                                        trace_kvm_guest_enter(vcpu);
                                }
                                spin_unlock(&mvc->lock);
                        }
                } else if (vc->vcore_state == VCORE_RUNNING &&
                           !VCORE_IS_EXITING(vc)) {
                        kvmppc_create_dtl_entry(vcpu, vc);
                        kvmppc_start_thread(vcpu, vc);
                        trace_kvm_guest_enter(vcpu);
                } else if (vc->vcore_state == VCORE_SLEEPING) {
                        wake_up(&vc->wq);
                }

        }

        while (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE &&
               !signal_pending(current)) {
                if (vc->vcore_state == VCORE_PREEMPT && vc->runner == NULL)
                        kvmppc_vcore_end_preempt(vc);

                if (vc->vcore_state != VCORE_INACTIVE) {
                        kvmppc_wait_for_exec(vc, vcpu, TASK_INTERRUPTIBLE);
                        continue;
                }
                list_for_each_entry_safe(v, vn, &vc->runnable_threads,
                                         arch.run_list) {
                        kvmppc_core_prepare_to_enter(v);
                        if (signal_pending(v->arch.run_task)) {
                                kvmppc_remove_runnable(vc, v);
                                v->stat.signal_exits++;
                                v->arch.kvm_run->exit_reason = KVM_EXIT_INTR;
                                v->arch.ret = -EINTR;
                                wake_up(&v->arch.cpu_run);
                        }
                }
                if (!vc->n_runnable || vcpu->arch.state != KVMPPC_VCPU_RUNNABLE)
                        break;
                n_ceded = 0;
                list_for_each_entry(v, &vc->runnable_threads, arch.run_list) {
                        if (!v->arch.pending_exceptions)
                                n_ceded += v->arch.ceded;
                        else
                                v->arch.ceded = 0;
                }
                vc->runner = vcpu;
                if (n_ceded == vc->n_runnable) {
                        kvmppc_vcore_blocked(vc);
                } else if (need_resched()) {
                        kvmppc_vcore_preempt(vc);
                        /* Let something else run */
                        cond_resched_lock(&vc->lock);
                        if (vc->vcore_state == VCORE_PREEMPT)
                                kvmppc_vcore_end_preempt(vc);
                } else {
                        kvmppc_run_core(vc);
                }
                vc->runner = NULL;
        }

        while (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE &&
               (vc->vcore_state == VCORE_RUNNING ||
                vc->vcore_state == VCORE_EXITING ||
                vc->vcore_state == VCORE_PIGGYBACK))
                kvmppc_wait_for_exec(vc, vcpu, TASK_UNINTERRUPTIBLE);

        if (vc->vcore_state == VCORE_PREEMPT && vc->runner == NULL)
                kvmppc_vcore_end_preempt(vc);

        if (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE) {
                kvmppc_remove_runnable(vc, vcpu);
                vcpu->stat.signal_exits++;
                kvm_run->exit_reason = KVM_EXIT_INTR;
                vcpu->arch.ret = -EINTR;
        }

        if (vc->n_runnable && vc->vcore_state == VCORE_INACTIVE) {
                /* Wake up some vcpu to run the core */
                v = list_first_entry(&vc->runnable_threads,
                                     struct kvm_vcpu, arch.run_list);
                wake_up(&v->arch.cpu_run);
        }

        trace_kvmppc_run_vcpu_exit(vcpu, kvm_run);
        spin_unlock(&vc->lock);
        return vcpu->arch.ret;
}

static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu)
{
        int r;
        int srcu_idx;
        unsigned long ebb_regs[3] = {}; /* shut up GCC */
        unsigned long user_tar = 0;
        unsigned long proc_fscr = 0;
        unsigned int user_vrsave;

        if (!vcpu->arch.sane) {
                run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
                return -EINVAL;
        }

        /*
         * Don't allow entry with a suspended transaction, because
         * the guest entry/exit code will lose it.
         * If the guest has TM enabled, save away their TM-related SPRs
         * (they will get restored by the TM unavailable interrupt).
         */
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
        if (cpu_has_feature(CPU_FTR_TM) && current->thread.regs &&
            (current->thread.regs->msr & MSR_TM)) {
                if (MSR_TM_ACTIVE(current->thread.regs->msr)) {
                        run->exit_reason = KVM_EXIT_FAIL_ENTRY;
                        run->fail_entry.hardware_entry_failure_reason = 0;
                        return -EINVAL;
                }
                /* Enable TM so we can read the TM SPRs */
                mtmsr(mfmsr() | MSR_TM);
                current->thread.tm_tfhar = mfspr(SPRN_TFHAR);
                current->thread.tm_tfiar = mfspr(SPRN_TFIAR);
                current->thread.tm_texasr = mfspr(SPRN_TEXASR);
        }
#endif

        kvmppc_core_prepare_to_enter(vcpu);

        /* No need to go into the guest when all we'll do is come back out */
        if (signal_pending(current)) {
                run->exit_reason = KVM_EXIT_INTR;
                return -EINTR;
        }

        atomic_inc(&vcpu->kvm->arch.vcpus_running);
        /* Order vcpus_running vs. hpte_setup_done, see kvmppc_alloc_reset_hpt */
        smp_mb();

        /* On the first time here, set up HTAB and VRMA */
        if (!vcpu->kvm->arch.hpte_setup_done) {
                r = kvmppc_hv_setup_htab_rma(vcpu);
                if (r)
                        goto out;
        }

        flush_fp_to_thread(current);
        flush_altivec_to_thread(current);
        flush_vsx_to_thread(current);

        /* Save userspace EBB and other register values */
        if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
                ebb_regs[0] = mfspr(SPRN_EBBHR);
                ebb_regs[1] = mfspr(SPRN_EBBRR);
                ebb_regs[2] = mfspr(SPRN_BESCR);
                user_tar = mfspr(SPRN_TAR);
                proc_fscr = mfspr(SPRN_FSCR);
        }
        user_vrsave = mfspr(SPRN_VRSAVE);

        vcpu->arch.wqp = &vcpu->arch.vcore->wq;
        vcpu->arch.pgdir = current->mm->pgd;
        vcpu->arch.state = KVMPPC_VCPU_BUSY_IN_HOST;

        do {
                r = kvmppc_run_vcpu(run, vcpu);

                if (run->exit_reason == KVM_EXIT_PAPR_HCALL &&
                    !(vcpu->arch.shregs.msr & MSR_PR)) {
                        trace_kvm_hcall_enter(vcpu);
                        r = kvmppc_pseries_do_hcall(vcpu);
                        trace_kvm_hcall_exit(vcpu, r);
                        kvmppc_core_prepare_to_enter(vcpu);
                } else if (r == RESUME_PAGE_FAULT) {
                        srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
                        r = kvmppc_book3s_hv_page_fault(run, vcpu,
                                vcpu->arch.fault_dar, vcpu->arch.fault_dsisr);
                        srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx);
                }
        } while (is_kvmppc_resume_guest(r));

        /* Restore userspace EBB and other register values */
        if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
                mtspr(SPRN_EBBHR, ebb_regs[0]);
                mtspr(SPRN_EBBRR, ebb_regs[1]);
                mtspr(SPRN_BESCR, ebb_regs[2]);
                mtspr(SPRN_TAR, user_tar);
                mtspr(SPRN_FSCR, proc_fscr);
        }
        mtspr(SPRN_VRSAVE, user_vrsave);

        /*
         * Since we don't do lazy TM reload, we need to reload
         * the TM registers here.
         */
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
        if (cpu_has_feature(CPU_FTR_TM) && current->thread.regs &&
            (current->thread.regs->msr & MSR_TM)) {
                mtspr(SPRN_TFHAR, current->thread.tm_tfhar);
                mtspr(SPRN_TFIAR, current->thread.tm_tfiar);
                mtspr(SPRN_TEXASR, current->thread.tm_texasr);
        }
#endif

 out:
        vcpu->arch.state = KVMPPC_VCPU_NOTREADY;
        atomic_dec(&vcpu->kvm->arch.vcpus_running);
        return r;
}

static void kvmppc_add_seg_page_size(struct kvm_ppc_one_seg_page_size **sps,
                                     int linux_psize)
{
        struct mmu_psize_def *def = &mmu_psize_defs[linux_psize];

        if (!def->shift)
                return;
        (*sps)->page_shift = def->shift;
        (*sps)->slb_enc = def->sllp;
        (*sps)->enc[0].page_shift = def->shift;
        (*sps)->enc[0].pte_enc = def->penc[linux_psize];
        /*
         * Add 16MB MPSS support if host supports it
         */
        if (linux_psize != MMU_PAGE_16M && def->penc[MMU_PAGE_16M] != -1) {
                (*sps)->enc[1].page_shift = 24;
                (*sps)->enc[1].pte_enc = def->penc[MMU_PAGE_16M];
        }
        (*sps)++;
}

static int kvm_vm_ioctl_get_smmu_info_hv(struct kvm *kvm,
                                         struct kvm_ppc_smmu_info *info)
{
        struct kvm_ppc_one_seg_page_size *sps;

        info->flags = KVM_PPC_PAGE_SIZES_REAL;
        if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
                info->flags |= KVM_PPC_1T_SEGMENTS;
        info->slb_size = mmu_slb_size;

        /* We only support these sizes for now, and no muti-size segments */
        sps = &info->sps[0];
        kvmppc_add_seg_page_size(&sps, MMU_PAGE_4K);
        kvmppc_add_seg_page_size(&sps, MMU_PAGE_64K);
        kvmppc_add_seg_page_size(&sps, MMU_PAGE_16M);

        return 0;
}

/*
 * Get (and clear) the dirty memory log for a memory slot.
 */
static int kvm_vm_ioctl_get_dirty_log_hv(struct kvm *kvm,
                                         struct kvm_dirty_log *log)
{
        struct kvm_memslots *slots;
        struct kvm_memory_slot *memslot;
        int r;
        unsigned long n;

        mutex_lock(&kvm->slots_lock);

        r = -EINVAL;
        if (log->slot >= KVM_USER_MEM_SLOTS)
                goto out;

        slots = kvm_memslots(kvm);
        memslot = id_to_memslot(slots, log->slot);
        r = -ENOENT;
        if (!memslot->dirty_bitmap)
                goto out;

        n = kvm_dirty_bitmap_bytes(memslot);
        memset(memslot->dirty_bitmap, 0, n);

        r = kvmppc_hv_get_dirty_log(kvm, memslot, memslot->dirty_bitmap);
        if (r)
                goto out;

        r = -EFAULT;
        if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
                goto out;

        r = 0;
out:
        mutex_unlock(&kvm->slots_lock);
        return r;
}

static void kvmppc_core_free_memslot_hv(struct kvm_memory_slot *free,
                                        struct kvm_memory_slot *dont)
{
        if (!dont || free->arch.rmap != dont->arch.rmap) {
                vfree(free->arch.rmap);
                free->arch.rmap = NULL;
        }
}

static int kvmppc_core_create_memslot_hv(struct kvm_memory_slot *slot,
                                         unsigned long npages)
{
        slot->arch.rmap = vzalloc(npages * sizeof(*slot->arch.rmap));
        if (!slot->arch.rmap)
                return -ENOMEM;

        return 0;
}

static int kvmppc_core_prepare_memory_region_hv(struct kvm *kvm,
                                        struct kvm_memory_slot *memslot,
                                        const struct kvm_userspace_memory_region *mem)
{
        return 0;
}

static void kvmppc_core_commit_memory_region_hv(struct kvm *kvm,
                                const struct kvm_userspace_memory_region *mem,
                                const struct kvm_memory_slot *old,
                                const struct kvm_memory_slot *new)
{
        unsigned long npages = mem->memory_size >> PAGE_SHIFT;
        struct kvm_memslots *slots;
        struct kvm_memory_slot *memslot;

        if (npages && old->npages) {
                /*
                 * If modifying a memslot, reset all the rmap dirty bits.
                 * If this is a new memslot, we don't need to do anything
                 * since the rmap array starts out as all zeroes,
                 * i.e. no pages are dirty.
                 */
                slots = kvm_memslots(kvm);
                memslot = id_to_memslot(slots, mem->slot);
                kvmppc_hv_get_dirty_log(kvm, memslot, NULL);
        }
}

/*
 * Update LPCR values in kvm->arch and in vcores.
 * Caller must hold kvm->lock.
 */
void kvmppc_update_lpcr(struct kvm *kvm, unsigned long lpcr, unsigned long mask)
{
        long int i;
        u32 cores_done = 0;

        if ((kvm->arch.lpcr & mask) == lpcr)
                return;

        kvm->arch.lpcr = (kvm->arch.lpcr & ~mask) | lpcr;

        for (i = 0; i < KVM_MAX_VCORES; ++i) {
                struct kvmppc_vcore *vc = kvm->arch.vcores[i];
                if (!vc)
                        continue;
                spin_lock(&vc->lock);
                vc->lpcr = (vc->lpcr & ~mask) | lpcr;
                spin_unlock(&vc->lock);
                if (++cores_done >= kvm->arch.online_vcores)
                        break;
        }
}

static void kvmppc_mmu_destroy_hv(struct kvm_vcpu *vcpu)
{
        return;
}

static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu)
{
        int err = 0;
        struct kvm *kvm = vcpu->kvm;
        unsigned long hva;
        struct kvm_memory_slot *memslot;
        struct vm_area_struct *vma;
        unsigned long lpcr = 0, senc;
        unsigned long psize, porder;
        int srcu_idx;

        mutex_lock(&kvm->lock);
        if (kvm->arch.hpte_setup_done)
                goto out;       /* another vcpu beat us to it */

        /* Allocate hashed page table (if not done already) and reset it */
        if (!kvm->arch.hpt_virt) {
                err = kvmppc_alloc_hpt(kvm, NULL);
                if (err) {
                        pr_err("KVM: Couldn't alloc HPT\n");
                        goto out;
                }
        }

        /* Look up the memslot for guest physical address 0 */
        srcu_idx = srcu_read_lock(&kvm->srcu);
        memslot = gfn_to_memslot(kvm, 0);

        /* We must have some memory at 0 by now */
        err = -EINVAL;
        if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
                goto out_srcu;

        /* Look up the VMA for the start of this memory slot */
        hva = memslot->userspace_addr;
        down_read(&current->mm->mmap_sem);
        vma = find_vma(current->mm, hva);
        if (!vma || vma->vm_start > hva || (vma->vm_flags & VM_IO))
                goto up_out;

        psize = vma_kernel_pagesize(vma);

        up_read(&current->mm->mmap_sem);

        /* We can handle 4k, 64k or 16M pages in the VRMA */
        if (psize >= 0x1000000)
                psize = 0x1000000;
        else if (psize >= 0x10000)
                psize = 0x10000;
        else
                psize = 0x1000;
        porder = __ilog2(psize);

        /* Update VRMASD field in the LPCR */
        senc = slb_pgsize_encoding(psize);
        kvm->arch.vrma_slb_v = senc | SLB_VSID_B_1T |
                (VRMA_VSID << SLB_VSID_SHIFT_1T);
        /* the -4 is to account for senc values starting at 0x10 */
        lpcr = senc << (LPCR_VRMASD_SH - 4);

        /* Create HPTEs in the hash page table for the VRMA */
        kvmppc_map_vrma(vcpu, memslot, porder);

        kvmppc_update_lpcr(kvm, lpcr, LPCR_VRMASD);

        /* Order updates to kvm->arch.lpcr etc. vs. hpte_setup_done */
        smp_wmb();
        kvm->arch.hpte_setup_done = 1;
        err = 0;
 out_srcu:
        srcu_read_unlock(&kvm->srcu, srcu_idx);
 out:
        mutex_unlock(&kvm->lock);
        return err;

 up_out:
        up_read(&current->mm->mmap_sem);
        goto out_srcu;
}

static int kvmppc_core_init_vm_hv(struct kvm *kvm)
{
        unsigned long lpcr, lpid;
        char buf[32];

        /* Allocate the guest's logical partition ID */

        lpid = kvmppc_alloc_lpid();
        if ((long)lpid < 0)
                return -ENOMEM;
        kvm->arch.lpid = lpid;

        /*
         * Since we don't flush the TLB when tearing down a VM,
         * and this lpid might have previously been used,
         * make sure we flush on each core before running the new VM.
         */
        cpumask_setall(&kvm->arch.need_tlb_flush);

        /* Start out with the default set of hcalls enabled */
        memcpy(kvm->arch.enabled_hcalls, default_enabled_hcalls,
               sizeof(kvm->arch.enabled_hcalls));

        kvm->arch.host_sdr1 = mfspr(SPRN_SDR1);

        /* Init LPCR for virtual RMA mode */
        kvm->arch.host_lpid = mfspr(SPRN_LPID);
        kvm->arch.host_lpcr = lpcr = mfspr(SPRN_LPCR);
        lpcr &= LPCR_PECE | LPCR_LPES;
        lpcr |= (4UL << LPCR_DPFD_SH) | LPCR_HDICE |
                LPCR_VPM0 | LPCR_VPM1;
        kvm->arch.vrma_slb_v = SLB_VSID_B_1T |
                (VRMA_VSID << SLB_VSID_SHIFT_1T);
        /* On POWER8 turn on online bit to enable PURR/SPURR */
        if (cpu_has_feature(CPU_FTR_ARCH_207S))
                lpcr |= LPCR_ONL;
        kvm->arch.lpcr = lpcr;

        /*
         * Track that we now have a HV mode VM active. This blocks secondary
         * CPU threads from coming online.
         */
        kvm_hv_vm_activated();

        /*
         * Create a debugfs directory for the VM
         */
        snprintf(buf, sizeof(buf), "vm%d", current->pid);
        kvm->arch.debugfs_dir = debugfs_create_dir(buf, kvm_debugfs_dir);
        if (!IS_ERR_OR_NULL(kvm->arch.debugfs_dir))
                kvmppc_mmu_debugfs_init(kvm);

        return 0;
}

static void kvmppc_free_vcores(struct kvm *kvm)
{
        long int i;

        for (i = 0; i < KVM_MAX_VCORES; ++i)
                kfree(kvm->arch.vcores[i]);
        kvm->arch.online_vcores = 0;
}

static void kvmppc_core_destroy_vm_hv(struct kvm *kvm)
{
        debugfs_remove_recursive(kvm->arch.debugfs_dir);

        kvm_hv_vm_deactivated();

        kvmppc_free_vcores(kvm);

        kvmppc_free_hpt(kvm);
}

/* We don't need to emulate any privileged instructions or dcbz */
static int kvmppc_core_emulate_op_hv(struct kvm_run *run, struct kvm_vcpu *vcpu,
                                     unsigned int inst, int *advance)
{
        return EMULATE_FAIL;
}

static int kvmppc_core_emulate_mtspr_hv(struct kvm_vcpu *vcpu, int sprn,
                                        ulong spr_val)
{
        return EMULATE_FAIL;
}

static int kvmppc_core_emulate_mfspr_hv(struct kvm_vcpu *vcpu, int sprn,
                                        ulong *spr_val)
{
        return EMULATE_FAIL;
}

static int kvmppc_core_check_processor_compat_hv(void)
{
        if (!cpu_has_feature(CPU_FTR_HVMODE) ||
            !cpu_has_feature(CPU_FTR_ARCH_206))
                return -EIO;
        return 0;
}

static long kvm_arch_vm_ioctl_hv(struct file *filp,
                                 unsigned int ioctl, unsigned long arg)
{
        struct kvm *kvm __maybe_unused = filp->private_data;
        void __user *argp = (void __user *)arg;
        long r;

        switch (ioctl) {

        case KVM_PPC_ALLOCATE_HTAB: {
                u32 htab_order;

                r = -EFAULT;
                if (get_user(htab_order, (u32 __user *)argp))
                        break;
                r = kvmppc_alloc_reset_hpt(kvm, &htab_order);
                if (r)
                        break;
                r = -EFAULT;
                if (put_user(htab_order, (u32 __user *)argp))
                        break;
                r = 0;
                break;
        }

        case KVM_PPC_GET_HTAB_FD: {
                struct kvm_get_htab_fd ghf;

                r = -EFAULT;
                if (copy_from_user(&ghf, argp, sizeof(ghf)))
                        break;
                r = kvm_vm_ioctl_get_htab_fd(kvm, &ghf);
                break;
        }

        default:
                r = -ENOTTY;
        }

        return r;
}

/*
 * List of hcall numbers to enable by default.
 * For compatibility with old userspace, we enable by default
 * all hcalls that were implemented before the hcall-enabling
 * facility was added.  Note this list should not include H_RTAS.
 */
static unsigned int default_hcall_list[] = {
        H_REMOVE,
        H_ENTER,
        H_READ,
        H_PROTECT,
        H_BULK_REMOVE,
        H_GET_TCE,
        H_PUT_TCE,
        H_SET_DABR,
        H_SET_XDABR,
        H_CEDE,
        H_PROD,
        H_CONFER,
        H_REGISTER_VPA,
#ifdef CONFIG_KVM_XICS
        H_EOI,
        H_CPPR,
        H_IPI,
        H_IPOLL,
        H_XIRR,
        H_XIRR_X,
#endif
        0
};

static void init_default_hcalls(void)
{
        int i;
        unsigned int hcall;

        for (i = 0; default_hcall_list[i]; ++i) {
                hcall = default_hcall_list[i];
                WARN_ON(!kvmppc_hcall_impl_hv(hcall));
                __set_bit(hcall / 4, default_enabled_hcalls);
        }
}

static struct kvmppc_ops kvm_ops_hv = {
        .get_sregs = kvm_arch_vcpu_ioctl_get_sregs_hv,
        .set_sregs = kvm_arch_vcpu_ioctl_set_sregs_hv,
        .get_one_reg = kvmppc_get_one_reg_hv,
        .set_one_reg = kvmppc_set_one_reg_hv,
        .vcpu_load   = kvmppc_core_vcpu_load_hv,
        .vcpu_put    = kvmppc_core_vcpu_put_hv,
        .set_msr     = kvmppc_set_msr_hv,
        .vcpu_run    = kvmppc_vcpu_run_hv,
        .vcpu_create = kvmppc_core_vcpu_create_hv,
        .vcpu_free   = kvmppc_core_vcpu_free_hv,
        .check_requests = kvmppc_core_check_requests_hv,
        .get_dirty_log  = kvm_vm_ioctl_get_dirty_log_hv,
        .flush_memslot  = kvmppc_core_flush_memslot_hv,
        .prepare_memory_region = kvmppc_core_prepare_memory_region_hv,
        .commit_memory_region  = kvmppc_core_commit_memory_region_hv,
        .unmap_hva = kvm_unmap_hva_hv,
        .unmap_hva_range = kvm_unmap_hva_range_hv,
        .age_hva  = kvm_age_hva_hv,
        .test_age_hva = kvm_test_age_hva_hv,
        .set_spte_hva = kvm_set_spte_hva_hv,
        .mmu_destroy  = kvmppc_mmu_destroy_hv,
        .free_memslot = kvmppc_core_free_memslot_hv,
        .create_memslot = kvmppc_core_create_memslot_hv,
        .init_vm =  kvmppc_core_init_vm_hv,
        .destroy_vm = kvmppc_core_destroy_vm_hv,
        .get_smmu_info = kvm_vm_ioctl_get_smmu_info_hv,
        .emulate_op = kvmppc_core_emulate_op_hv,
        .emulate_mtspr = kvmppc_core_emulate_mtspr_hv,
        .emulate_mfspr = kvmppc_core_emulate_mfspr_hv,
        .fast_vcpu_kick = kvmppc_fast_vcpu_kick_hv,
        .arch_vm_ioctl  = kvm_arch_vm_ioctl_hv,
        .hcall_implemented = kvmppc_hcall_impl_hv,
};

static int kvmppc_book3s_init_hv(void)
{
        int r;
        /*
         * FIXME!! Do we need to check on all cpus ?
         */
        r = kvmppc_core_check_processor_compat_hv();
        if (r < 0)
                return -ENODEV;

        kvm_ops_hv.owner = THIS_MODULE;
        kvmppc_hv_ops = &kvm_ops_hv;

        init_default_hcalls();

        init_vcore_lists();

        r = kvmppc_mmu_hv_init();
        return r;
}

static void kvmppc_book3s_exit_hv(void)
{
        kvmppc_hv_ops = NULL;
}

module_init(kvmppc_book3s_init_hv);
module_exit(kvmppc_book3s_exit_hv);
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(KVM_MINOR);
MODULE_ALIAS("devname:kvm");