arch/arm/xen/p2m.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/memblock.h>
   3 #include <linux/gfp.h>
   4 #include <linux/export.h>
   5 #include <linux/spinlock.h>
   6 #include <linux/slab.h>
   7 #include <linux/types.h>
   8 #include <linux/dma-mapping.h>
   9 #include <linux/vmalloc.h>
  10 #include <linux/swiotlb.h>
  11
  12 #include <xen/xen.h>
  13 #include <xen/interface/memory.h>
  14 #include <xen/grant_table.h>
  15 #include <xen/page.h>
  16 #include <xen/swiotlb-xen.h>
  17
  18 #include <asm/cacheflush.h>
  19 #include <asm/xen/hypercall.h>
  20 #include <asm/xen/interface.h>
  21
  22 struct xen_p2m_entry {
  23         unsigned long pfn;
  24         unsigned long mfn;
  25         unsigned long nr_pages;
  26         struct rb_node rbnode_phys;
  27 };
  28
  29 static rwlock_t p2m_lock;
  30 struct rb_root phys_to_mach = RB_ROOT;
  31 EXPORT_SYMBOL_GPL(phys_to_mach);
  32
  33 static int xen_add_phys_to_mach_entry(struct xen_p2m_entry *new)
  34 {
  35         struct rb_node **link = &phys_to_mach.rb_node;
  36         struct rb_node *parent = NULL;
  37         struct xen_p2m_entry *entry;
  38         int rc = 0;
  39
  40         while (*link) {
  41                 parent = *link;
  42                 entry = rb_entry(parent, struct xen_p2m_entry, rbnode_phys);
  43
  44                 if (new->pfn == entry->pfn)
  45                         goto err_out;
  46
  47                 if (new->pfn < entry->pfn)
  48                         link = &(*link)->rb_left;
  49                 else
  50                         link = &(*link)->rb_right;
  51         }
  52         rb_link_node(&new->rbnode_phys, parent, link);
  53         rb_insert_color(&new->rbnode_phys, &phys_to_mach);
  54         goto out;
  55
  56 err_out:
  57         rc = -EINVAL;
  58         pr_warn("%s: cannot add pfn=%pa -> mfn=%pa: pfn=%pa -> mfn=%pa already exists\n",
  59                         __func__, &new->pfn, &new->mfn, &entry->pfn, &entry->mfn);
  60 out:
  61         return rc;
  62 }
  63
  64 unsigned long __pfn_to_mfn(unsigned long pfn)
  65 {
  66         struct rb_node *n = phys_to_mach.rb_node;
  67         struct xen_p2m_entry *entry;
  68         unsigned long irqflags;
  69
  70         read_lock_irqsave(&p2m_lock, irqflags);
  71         while (n) {
  72                 entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
  73                 if (entry->pfn <= pfn &&
  74                                 entry->pfn + entry->nr_pages > pfn) {
  75                         unsigned long mfn = entry->mfn + (pfn - entry->pfn);
  76                         read_unlock_irqrestore(&p2m_lock, irqflags);
  77                         return mfn;
  78                 }
  79                 if (pfn < entry->pfn)
  80                         n = n->rb_left;
  81                 else
  82                         n = n->rb_right;
  83         }
  84         read_unlock_irqrestore(&p2m_lock, irqflags);
  85
  86         return INVALID_P2M_ENTRY;
  87 }
  88 EXPORT_SYMBOL_GPL(__pfn_to_mfn);
  89
  90 int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
  91                             struct gnttab_map_grant_ref *kmap_ops,
  92                             struct page **pages, unsigned int count)
  93 {
  94         int i;
  95
  96         for (i = 0; i < count; i++) {
  97                 struct gnttab_unmap_grant_ref unmap;
  98                 int rc;
  99
 100                 if (map_ops[i].status)
 101                         continue;
 102                 if (likely(set_phys_to_machine(map_ops[i].host_addr >> XEN_PAGE_SHIFT,
 103                                     map_ops[i].dev_bus_addr >> XEN_PAGE_SHIFT)))
 104                         continue;
 105
 106                 /*
 107                  * Signal an error for this slot. This in turn requires
 108                  * immediate unmapping.
 109                  */
 110                 map_ops[i].status = GNTST_general_error;
 111                 unmap.host_addr = map_ops[i].host_addr,
 112                 unmap.handle = map_ops[i].handle;
 113                 map_ops[i].handle = INVALID_GRANT_HANDLE;
 114                 if (map_ops[i].flags & GNTMAP_device_map)
 115                         unmap.dev_bus_addr = map_ops[i].dev_bus_addr;
 116                 else
 117                         unmap.dev_bus_addr = 0;
 118
 119                 /*
 120                  * Pre-populate the status field, to be recognizable in
 121                  * the log message below.
 122                  */
 123                 unmap.status = 1;
 124
 125                 rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
 126                                                &unmap, 1);
 127                 if (rc || unmap.status != GNTST_okay)
 128                         pr_err_once("gnttab unmap failed: rc=%d st=%d\n",
 129                                     rc, unmap.status);
 130         }
 131
 132         return 0;
 133 }
 134
 135 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
 136                               struct gnttab_unmap_grant_ref *kunmap_ops,
 137                               struct page **pages, unsigned int count)
 138 {
 139         int i;
 140
 141         for (i = 0; i < count; i++) {
 142                 set_phys_to_machine(unmap_ops[i].host_addr >> XEN_PAGE_SHIFT,
 143                                     INVALID_P2M_ENTRY);
 144         }
 145
 146         return 0;
 147 }
 148
 149 bool __set_phys_to_machine_multi(unsigned long pfn,
 150                 unsigned long mfn, unsigned long nr_pages)
 151 {
 152         int rc;
 153         unsigned long irqflags;
 154         struct xen_p2m_entry *p2m_entry;
 155         struct rb_node *n = phys_to_mach.rb_node;
 156
 157         if (mfn == INVALID_P2M_ENTRY) {
 158                 write_lock_irqsave(&p2m_lock, irqflags);
 159                 while (n) {
 160                         p2m_entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
 161                         if (p2m_entry->pfn <= pfn &&
 162                                         p2m_entry->pfn + p2m_entry->nr_pages > pfn) {
 163                                 rb_erase(&p2m_entry->rbnode_phys, &phys_to_mach);
 164                                 write_unlock_irqrestore(&p2m_lock, irqflags);
 165                                 kfree(p2m_entry);
 166                                 return true;
 167                         }
 168                         if (pfn < p2m_entry->pfn)
 169                                 n = n->rb_left;
 170                         else
 171                                 n = n->rb_right;
 172                 }
 173                 write_unlock_irqrestore(&p2m_lock, irqflags);
 174                 return true;
 175         }
 176
 177         p2m_entry = kzalloc(sizeof(*p2m_entry), GFP_NOWAIT);
 178         if (!p2m_entry)
 179                 return false;
 180
 181         p2m_entry->pfn = pfn;
 182         p2m_entry->nr_pages = nr_pages;
 183         p2m_entry->mfn = mfn;
 184
 185         write_lock_irqsave(&p2m_lock, irqflags);
 186         rc = xen_add_phys_to_mach_entry(p2m_entry);
 187         if (rc < 0) {
 188                 write_unlock_irqrestore(&p2m_lock, irqflags);
 189                 kfree(p2m_entry);
 190                 return false;
 191         }
 192         write_unlock_irqrestore(&p2m_lock, irqflags);
 193         return true;
 194 }
 195 EXPORT_SYMBOL_GPL(__set_phys_to_machine_multi);
 196
 197 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 198 {
 199         return __set_phys_to_machine_multi(pfn, mfn, 1);
 200 }
 201 EXPORT_SYMBOL_GPL(__set_phys_to_machine);
 202
 203 static int p2m_init(void)
 204 {
 205         rwlock_init(&p2m_lock);
 206         return 0;
 207 }
 208 arch_initcall(p2m_init);