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/page.h>
  15 #include <xen/swiotlb-xen.h>
  16
  17 #include <asm/cacheflush.h>
  18 #include <asm/xen/hypercall.h>
  19 #include <asm/xen/interface.h>
  20
  21 struct xen_p2m_entry {
  22         unsigned long pfn;
  23         unsigned long mfn;
  24         unsigned long nr_pages;
  25         struct rb_node rbnode_phys;
  26 };
  27
  28 static rwlock_t p2m_lock;
  29 struct rb_root phys_to_mach = RB_ROOT;
  30 EXPORT_SYMBOL_GPL(phys_to_mach);
  31
  32 static int xen_add_phys_to_mach_entry(struct xen_p2m_entry *new)
  33 {
  34         struct rb_node **link = &phys_to_mach.rb_node;
  35         struct rb_node *parent = NULL;
  36         struct xen_p2m_entry *entry;
  37         int rc = 0;
  38
  39         while (*link) {
  40                 parent = *link;
  41                 entry = rb_entry(parent, struct xen_p2m_entry, rbnode_phys);
  42
  43                 if (new->pfn == entry->pfn)
  44                         goto err_out;
  45
  46                 if (new->pfn < entry->pfn)
  47                         link = &(*link)->rb_left;
  48                 else
  49                         link = &(*link)->rb_right;
  50         }
  51         rb_link_node(&new->rbnode_phys, parent, link);
  52         rb_insert_color(&new->rbnode_phys, &phys_to_mach);
  53         goto out;
  54
  55 err_out:
  56         rc = -EINVAL;
  57         pr_warn("%s: cannot add pfn=%pa -> mfn=%pa: pfn=%pa -> mfn=%pa already exists\n",
  58                         __func__, &new->pfn, &new->mfn, &entry->pfn, &entry->mfn);
  59 out:
  60         return rc;
  61 }
  62
  63 unsigned long __pfn_to_mfn(unsigned long pfn)
  64 {
  65         struct rb_node *n;
  66         struct xen_p2m_entry *entry;
  67         unsigned long irqflags;
  68
  69         read_lock_irqsave(&p2m_lock, irqflags);
  70         n = phys_to_mach.rb_node;
  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 = ~0;
 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 EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);
 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 EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);
 150
 151 bool __set_phys_to_machine_multi(unsigned long pfn,
 152                 unsigned long mfn, unsigned long nr_pages)
 153 {
 154         int rc;
 155         unsigned long irqflags;
 156         struct xen_p2m_entry *p2m_entry;
 157         struct rb_node *n;
 158
 159         if (mfn == INVALID_P2M_ENTRY) {
 160                 write_lock_irqsave(&p2m_lock, irqflags);
 161                 n = phys_to_mach.rb_node;
 162                 while (n) {
 163                         p2m_entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
 164                         if (p2m_entry->pfn <= pfn &&
 165                                         p2m_entry->pfn + p2m_entry->nr_pages > pfn) {
 166                                 rb_erase(&p2m_entry->rbnode_phys, &phys_to_mach);
 167                                 write_unlock_irqrestore(&p2m_lock, irqflags);
 168                                 kfree(p2m_entry);
 169                                 return true;
 170                         }
 171                         if (pfn < p2m_entry->pfn)
 172                                 n = n->rb_left;
 173                         else
 174                                 n = n->rb_right;
 175                 }
 176                 write_unlock_irqrestore(&p2m_lock, irqflags);
 177                 return true;
 178         }
 179
 180         p2m_entry = kzalloc(sizeof(*p2m_entry), GFP_NOWAIT);
 181         if (!p2m_entry)
 182                 return false;
 183
 184         p2m_entry->pfn = pfn;
 185         p2m_entry->nr_pages = nr_pages;
 186         p2m_entry->mfn = mfn;
 187
 188         write_lock_irqsave(&p2m_lock, irqflags);
 189         rc = xen_add_phys_to_mach_entry(p2m_entry);
 190         if (rc < 0) {
 191                 write_unlock_irqrestore(&p2m_lock, irqflags);
 192                 kfree(p2m_entry);
 193                 return false;
 194         }
 195         write_unlock_irqrestore(&p2m_lock, irqflags);
 196         return true;
 197 }
 198 EXPORT_SYMBOL_GPL(__set_phys_to_machine_multi);
 199
 200 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 201 {
 202         return __set_phys_to_machine_multi(pfn, mfn, 1);
 203 }
 204 EXPORT_SYMBOL_GPL(__set_phys_to_machine);
 205
 206 static int p2m_init(void)
 207 {
 208         rwlock_init(&p2m_lock);
 209         return 0;
 210 }
 211 arch_initcall(p2m_init);