tools/testing/selftests/kvm/cr4_cpuid_sync_test.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * CR4 and CPUID sync test
   4  *
   5  * Copyright 2018, Red Hat, Inc. and/or its affiliates.
   6  *
   7  * Author:
   8  *   Wei Huang <wei@redhat.com>
   9  */
  10
  11 #include <fcntl.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <sys/ioctl.h>
  16
  17 #include "test_util.h"
  18
  19 #include "kvm_util.h"
  20 #include "x86.h"
  21
  22 #define X86_FEATURE_XSAVE       (1<<26)
  23 #define X86_FEATURE_OSXSAVE     (1<<27)
  24 #define VCPU_ID                 1
  25
  26 static inline bool cr4_cpuid_is_sync(void)
  27 {
  28         int func, subfunc;
  29         uint32_t eax, ebx, ecx, edx;
  30         uint64_t cr4;
  31
  32         func = 0x1;
  33         subfunc = 0x0;
  34         __asm__ __volatile__("cpuid"
  35                              : "=a"(eax), "=b"(ebx), "=c"(ecx), "=d"(edx)
  36                              : "a"(func), "c"(subfunc));
  37
  38         cr4 = get_cr4();
  39
  40         return (!!(ecx & X86_FEATURE_OSXSAVE)) == (!!(cr4 & X86_CR4_OSXSAVE));
  41 }
  42
  43 static void guest_code(void)
  44 {
  45         uint64_t cr4;
  46
  47         /* turn on CR4.OSXSAVE */
  48         cr4 = get_cr4();
  49         cr4 |= X86_CR4_OSXSAVE;
  50         set_cr4(cr4);
  51
  52         /* verify CR4.OSXSAVE == CPUID.OSXSAVE */
  53         GUEST_ASSERT(cr4_cpuid_is_sync());
  54
  55         /* notify hypervisor to change CR4 */
  56         GUEST_SYNC(0);
  57
  58         /* check again */
  59         GUEST_ASSERT(cr4_cpuid_is_sync());
  60
  61         GUEST_DONE();
  62 }
  63
  64 int main(int argc, char *argv[])
  65 {
  66         struct kvm_run *run;
  67         struct kvm_vm *vm;
  68         struct kvm_sregs sregs;
  69         struct kvm_cpuid_entry2 *entry;
  70         int rc;
  71
  72         entry = kvm_get_supported_cpuid_entry(1);
  73         if (!(entry->ecx & X86_FEATURE_XSAVE)) {
  74                 printf("XSAVE feature not supported, skipping test\n");
  75                 return 0;
  76         }
  77
  78         /* Tell stdout not to buffer its content */
  79         setbuf(stdout, NULL);
  80
  81         /* Create VM */
  82         vm = vm_create_default(VCPU_ID, 0, guest_code);
  83         vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
  84         run = vcpu_state(vm, VCPU_ID);
  85
  86         while (1) {
  87                 rc = _vcpu_run(vm, VCPU_ID);
  88
  89                 if (run->exit_reason == KVM_EXIT_IO) {
  90                         switch (run->io.port) {
  91                         case GUEST_PORT_SYNC:
  92                                 /* emulate hypervisor clearing CR4.OSXSAVE */
  93                                 vcpu_sregs_get(vm, VCPU_ID, &sregs);
  94                                 sregs.cr4 &= ~X86_CR4_OSXSAVE;
  95                                 vcpu_sregs_set(vm, VCPU_ID, &sregs);
  96                                 break;
  97                         case GUEST_PORT_ABORT:
  98                                 TEST_ASSERT(false, "Guest CR4 bit (OSXSAVE) unsynchronized with CPUID bit.");
  99                                 break;
 100                         case GUEST_PORT_DONE:
 101                                 goto done;
 102                         default:
 103                                 TEST_ASSERT(false, "Unknown port 0x%x.",
 104                                             run->io.port);
 105                         }
 106                 }
 107         }
 108
 109         kvm_vm_free(vm);
 110
 111 done:
 112         return 0;
 113 }