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;
  67         struct xen_p2m_entry *entry;
  68         unsigned long irqflags;
  69
  70         read_lock_irqsave(&p2m_lock, irqflags);
  71         n = phys_to_mach.rb_node;
  72         while (n) {
  73                 entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
  74                 if (entry->pfn <= pfn &&
  75                                 entry->pfn + entry->nr_pages > pfn) {
  76                         unsigned long mfn = entry->mfn + (pfn - entry->pfn);
  77                         read_unlock_irqrestore(&p2m_lock, irqflags);
  78                         return mfn;
  79                 }
  80                 if (pfn < entry->pfn)
  81                         n = n->rb_left;
  82                 else
  83                         n = n->rb_right;
  84         }
  85         read_unlock_irqrestore(&p2m_lock, irqflags);
  86
  87         return INVALID_P2M_ENTRY;
  88 }
  89 EXPORT_SYMBOL_GPL(__pfn_to_mfn);
  90
  91 int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
  92                             struct gnttab_map_grant_ref *kmap_ops,
  93                             struct page **pages, unsigned int count)
  94 {
  95         int i;
  96
  97         for (i = 0; i < count; i++) {
  98                 struct gnttab_unmap_grant_ref unmap;
  99                 int rc;
 100
 101                 if (map_ops[i].status)
 102                         continue;
 103                 if (likely(set_phys_to_machine(map_ops[i].host_addr >> XEN_PAGE_SHIFT,
 104                                     map_ops[i].dev_bus_addr >> XEN_PAGE_SHIFT)))
 105                         continue;
 106
 107                 /*
 108                  * Signal an error for this slot. This in turn requires
 109                  * immediate unmapping.
 110                  */
 111                 map_ops[i].status = GNTST_general_error;
 112                 unmap.host_addr = map_ops[i].host_addr;
 113                 unmap.handle = map_ops[i].handle;
 114                 map_ops[i].handle = INVALID_GRANT_HANDLE;
 115                 if (map_ops[i].flags & GNTMAP_device_map)
 116                         unmap.dev_bus_addr = map_ops[i].dev_bus_addr;
 117                 else
 118                         unmap.dev_bus_addr = 0;
 119
 120                 /*
 121                  * Pre-populate the status field, to be recognizable in
 122                  * the log message below.
 123                  */
 124                 unmap.status = 1;
 125
 126                 rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
 127                                                &unmap, 1);
 128                 if (rc || unmap.status != GNTST_okay)
 129                         pr_err_once("gnttab unmap failed: rc=%d st=%d\n",
 130                                     rc, unmap.status);
 131         }
 132
 133         return 0;
 134 }
 135
 136 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
 137                               struct gnttab_unmap_grant_ref *kunmap_ops,
 138                               struct page **pages, unsigned int count)
 139 {
 140         int i;
 141
 142         for (i = 0; i < count; i++) {
 143                 set_phys_to_machine(unmap_ops[i].host_addr >> XEN_PAGE_SHIFT,
 144                                     INVALID_P2M_ENTRY);
 145         }
 146
 147         return 0;
 148 }
 149
 150 bool __set_phys_to_machine_multi(unsigned long pfn,
 151                 unsigned long mfn, unsigned long nr_pages)
 152 {
 153         int rc;
 154         unsigned long irqflags;
 155         struct xen_p2m_entry *p2m_entry;
 156         struct rb_node *n;
 157
 158         if (mfn == INVALID_P2M_ENTRY) {
 159                 write_lock_irqsave(&p2m_lock, irqflags);
 160                 n = phys_to_mach.rb_node;
 161                 while (n) {
 162                         p2m_entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
 163                         if (p2m_entry->pfn <= pfn &&
 164                                         p2m_entry->pfn + p2m_entry->nr_pages > pfn) {
 165                                 rb_erase(&p2m_entry->rbnode_phys, &phys_to_mach);
 166                                 write_unlock_irqrestore(&p2m_lock, irqflags);
 167                                 kfree(p2m_entry);
 168                                 return true;
 169                         }
 170                         if (pfn < p2m_entry->pfn)
 171                                 n = n->rb_left;
 172                         else
 173                                 n = n->rb_right;
 174                 }
 175                 write_unlock_irqrestore(&p2m_lock, irqflags);
 176                 return true;
 177         }
 178
 179         p2m_entry = kzalloc(sizeof(*p2m_entry), GFP_NOWAIT);
 180         if (!p2m_entry)
 181                 return false;
 182
 183         p2m_entry->pfn = pfn;
 184         p2m_entry->nr_pages = nr_pages;
 185         p2m_entry->mfn = mfn;
 186
 187         write_lock_irqsave(&p2m_lock, irqflags);
 188         rc = xen_add_phys_to_mach_entry(p2m_entry);
 189         if (rc < 0) {
 190                 write_unlock_irqrestore(&p2m_lock, irqflags);
 191                 kfree(p2m_entry);
 192                 return false;
 193         }
 194         write_unlock_irqrestore(&p2m_lock, irqflags);
 195         return true;
 196 }
 197 EXPORT_SYMBOL_GPL(__set_phys_to_machine_multi);
 198
 199 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 200 {
 201         return __set_phys_to_machine_multi(pfn, mfn, 1);
 202 }
 203 EXPORT_SYMBOL_GPL(__set_phys_to_machine);
 204
 205 static int p2m_init(void)
 206 {
 207         rwlock_init(&p2m_lock);
 208         return 0;
 209 }
 210 arch_initcall(p2m_init);