arch/arm/xen/p2m.c

   1 #include <linux/bootmem.h>
   2 #include <linux/gfp.h>
   3 #include <linux/export.h>
   4 #include <linux/spinlock.h>
   5 #include <linux/slab.h>
   6 #include <linux/types.h>
   7 #include <linux/dma-mapping.h>
   8 #include <linux/vmalloc.h>
   9 #include <linux/swiotlb.h>
  10
  11 #include <xen/xen.h>
  12 #include <xen/interface/memory.h>
  13 #include <xen/page.h>
  14 #include <xen/swiotlb-xen.h>
  15
  16 #include <asm/cacheflush.h>
  17 #include <asm/xen/hypercall.h>
  18 #include <asm/xen/interface.h>
  19
  20 struct xen_p2m_entry {
  21         unsigned long pfn;
  22         unsigned long mfn;
  23         unsigned long nr_pages;
  24         struct rb_node rbnode_phys;
  25 };
  26
  27 static rwlock_t p2m_lock;
  28 struct rb_root phys_to_mach = RB_ROOT;
  29 EXPORT_SYMBOL_GPL(phys_to_mach);
  30
  31 static int xen_add_phys_to_mach_entry(struct xen_p2m_entry *new)
  32 {
  33         struct rb_node **link = &phys_to_mach.rb_node;
  34         struct rb_node *parent = NULL;
  35         struct xen_p2m_entry *entry;
  36         int rc = 0;
  37
  38         while (*link) {
  39                 parent = *link;
  40                 entry = rb_entry(parent, struct xen_p2m_entry, rbnode_phys);
  41
  42                 if (new->pfn == entry->pfn)
  43                         goto err_out;
  44
  45                 if (new->pfn < entry->pfn)
  46                         link = &(*link)->rb_left;
  47                 else
  48                         link = &(*link)->rb_right;
  49         }
  50         rb_link_node(&new->rbnode_phys, parent, link);
  51         rb_insert_color(&new->rbnode_phys, &phys_to_mach);
  52         goto out;
  53
  54 err_out:
  55         rc = -EINVAL;
  56         pr_warn("%s: cannot add pfn=%pa -> mfn=%pa: pfn=%pa -> mfn=%pa already exists\n",
  57                         __func__, &new->pfn, &new->mfn, &entry->pfn, &entry->mfn);
  58 out:
  59         return rc;
  60 }
  61
  62 unsigned long __pfn_to_mfn(unsigned long pfn)
  63 {
  64         struct rb_node *n = phys_to_mach.rb_node;
  65         struct xen_p2m_entry *entry;
  66         unsigned long irqflags;
  67
  68         read_lock_irqsave(&p2m_lock, irqflags);
  69         while (n) {
  70                 entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
  71                 if (entry->pfn <= pfn &&
  72                                 entry->pfn + entry->nr_pages > pfn) {
  73                         read_unlock_irqrestore(&p2m_lock, irqflags);
  74                         return entry->mfn + (pfn - entry->pfn);
  75                 }
  76                 if (pfn < entry->pfn)
  77                         n = n->rb_left;
  78                 else
  79                         n = n->rb_right;
  80         }
  81         read_unlock_irqrestore(&p2m_lock, irqflags);
  82
  83         return INVALID_P2M_ENTRY;
  84 }
  85 EXPORT_SYMBOL_GPL(__pfn_to_mfn);
  86
  87 int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
  88                             struct gnttab_map_grant_ref *kmap_ops,
  89                             struct page **pages, unsigned int count)
  90 {
  91         int i;
  92
  93         for (i = 0; i < count; i++) {
  94                 struct gnttab_unmap_grant_ref unmap;
  95                 int rc;
  96
  97                 if (map_ops[i].status)
  98                         continue;
  99                 if (likely(set_phys_to_machine(map_ops[i].host_addr >> XEN_PAGE_SHIFT,
 100                                     map_ops[i].dev_bus_addr >> XEN_PAGE_SHIFT)))
 101                         continue;
 102
 103                 /*
 104                  * Signal an error for this slot. This in turn requires
 105                  * immediate unmapping.
 106                  */
 107                 map_ops[i].status = GNTST_general_error;
 108                 unmap.host_addr = map_ops[i].host_addr,
 109                 unmap.handle = map_ops[i].handle;
 110                 map_ops[i].handle = ~0;
 111                 if (map_ops[i].flags & GNTMAP_device_map)
 112                         unmap.dev_bus_addr = map_ops[i].dev_bus_addr;
 113                 else
 114                         unmap.dev_bus_addr = 0;
 115
 116                 /*
 117                  * Pre-populate the status field, to be recognizable in
 118                  * the log message below.
 119                  */
 120                 unmap.status = 1;
 121
 122                 rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
 123                                                &unmap, 1);
 124                 if (rc || unmap.status != GNTST_okay)
 125                         pr_err_once("gnttab unmap failed: rc=%d st=%d\n",
 126                                     rc, unmap.status);
 127         }
 128
 129         return 0;
 130 }
 131 EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);
 132
 133 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
 134                               struct gnttab_unmap_grant_ref *kunmap_ops,
 135                               struct page **pages, unsigned int count)
 136 {
 137         int i;
 138
 139         for (i = 0; i < count; i++) {
 140                 set_phys_to_machine(unmap_ops[i].host_addr >> XEN_PAGE_SHIFT,
 141                                     INVALID_P2M_ENTRY);
 142         }
 143
 144         return 0;
 145 }
 146 EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);
 147
 148 bool __set_phys_to_machine_multi(unsigned long pfn,
 149                 unsigned long mfn, unsigned long nr_pages)
 150 {
 151         int rc;
 152         unsigned long irqflags;
 153         struct xen_p2m_entry *p2m_entry;
 154         struct rb_node *n = phys_to_mach.rb_node;
 155
 156         if (mfn == INVALID_P2M_ENTRY) {
 157                 write_lock_irqsave(&p2m_lock, irqflags);
 158                 while (n) {
 159                         p2m_entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
 160                         if (p2m_entry->pfn <= pfn &&
 161                                         p2m_entry->pfn + p2m_entry->nr_pages > pfn) {
 162                                 rb_erase(&p2m_entry->rbnode_phys, &phys_to_mach);
 163                                 write_unlock_irqrestore(&p2m_lock, irqflags);
 164                                 kfree(p2m_entry);
 165                                 return true;
 166                         }
 167                         if (pfn < p2m_entry->pfn)
 168                                 n = n->rb_left;
 169                         else
 170                                 n = n->rb_right;
 171                 }
 172                 write_unlock_irqrestore(&p2m_lock, irqflags);
 173                 return true;
 174         }
 175
 176         p2m_entry = kzalloc(sizeof(*p2m_entry), GFP_NOWAIT);
 177         if (!p2m_entry)
 178                 return false;
 179
 180         p2m_entry->pfn = pfn;
 181         p2m_entry->nr_pages = nr_pages;
 182         p2m_entry->mfn = mfn;
 183
 184         write_lock_irqsave(&p2m_lock, irqflags);
 185         rc = xen_add_phys_to_mach_entry(p2m_entry);
 186         if (rc < 0) {
 187                 write_unlock_irqrestore(&p2m_lock, irqflags);
 188                 return false;
 189         }
 190         write_unlock_irqrestore(&p2m_lock, irqflags);
 191         return true;
 192 }
 193 EXPORT_SYMBOL_GPL(__set_phys_to_machine_multi);
 194
 195 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 196 {
 197         return __set_phys_to_machine_multi(pfn, mfn, 1);
 198 }
 199 EXPORT_SYMBOL_GPL(__set_phys_to_machine);
 200
 201 static int p2m_init(void)
 202 {
 203         rwlock_init(&p2m_lock);
 204         return 0;
 205 }
 206 arch_initcall(p2m_init);