arch/x86/xen/mmu.c

   1 #include <linux/pfn.h>
   2 #include <asm/xen/page.h>
   3 #include <asm/xen/hypercall.h>
   4 #include <xen/interface/memory.h>
   5
   6 #include "multicalls.h"
   7 #include "mmu.h"
   8
   9 /*
  10  * Protects atomic reservation decrease/increase against concurrent increases.
  11  * Also protects non-atomic updates of current_pages and balloon lists.
  12  */
  13 DEFINE_SPINLOCK(xen_reservation_lock);
  14
  15 unsigned long arbitrary_virt_to_mfn(void *vaddr)
  16 {
  17         xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);
  18
  19         return PFN_DOWN(maddr.maddr);
  20 }
  21
  22 xmaddr_t arbitrary_virt_to_machine(void *vaddr)
  23 {
  24         unsigned long address = (unsigned long)vaddr;
  25         unsigned int level;
  26         pte_t *pte;
  27         unsigned offset;
  28
  29         /*
  30          * if the PFN is in the linear mapped vaddr range, we can just use
  31          * the (quick) virt_to_machine() p2m lookup
  32          */
  33         if (virt_addr_valid(vaddr))
  34                 return virt_to_machine(vaddr);
  35
  36         /* otherwise we have to do a (slower) full page-table walk */
  37
  38         pte = lookup_address(address, &level);
  39         BUG_ON(pte == NULL);
  40         offset = address & ~PAGE_MASK;
  41         return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
  42 }
  43 EXPORT_SYMBOL_GPL(arbitrary_virt_to_machine);
  44
  45 static noinline void xen_flush_tlb_all(void)
  46 {
  47         struct mmuext_op *op;
  48         struct multicall_space mcs;
  49
  50         preempt_disable();
  51
  52         mcs = xen_mc_entry(sizeof(*op));
  53
  54         op = mcs.args;
  55         op->cmd = MMUEXT_TLB_FLUSH_ALL;
  56         MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
  57
  58         xen_mc_issue(PARAVIRT_LAZY_MMU);
  59
  60         preempt_enable();
  61 }
  62
  63 #define REMAP_BATCH_SIZE 16
  64
  65 struct remap_data {
  66         xen_pfn_t *pfn;
  67         bool contiguous;
  68         bool no_translate;
  69         pgprot_t prot;
  70         struct mmu_update *mmu_update;
  71 };
  72
  73 static int remap_area_pfn_pte_fn(pte_t *ptep, pgtable_t token,
  74                                  unsigned long addr, void *data)
  75 {
  76         struct remap_data *rmd = data;
  77         pte_t pte = pte_mkspecial(mfn_pte(*rmd->pfn, rmd->prot));
  78
  79         /*
  80          * If we have a contiguous range, just update the pfn itself,
  81          * else update pointer to be "next pfn".
  82          */
  83         if (rmd->contiguous)
  84                 (*rmd->pfn)++;
  85         else
  86                 rmd->pfn++;
  87
  88         rmd->mmu_update->ptr = virt_to_machine(ptep).maddr;
  89         rmd->mmu_update->ptr |= rmd->no_translate ?
  90                 MMU_PT_UPDATE_NO_TRANSLATE :
  91                 MMU_NORMAL_PT_UPDATE;
  92         rmd->mmu_update->val = pte_val_ma(pte);
  93         rmd->mmu_update++;
  94
  95         return 0;
  96 }
  97
  98 static int do_remap_pfn(struct vm_area_struct *vma,
  99                         unsigned long addr,
 100                         xen_pfn_t *pfn, int nr,
 101                         int *err_ptr, pgprot_t prot,
 102                         unsigned int domid,
 103                         bool no_translate,
 104                         struct page **pages)
 105 {
 106         int err = 0;
 107         struct remap_data rmd;
 108         struct mmu_update mmu_update[REMAP_BATCH_SIZE];
 109         unsigned long range;
 110         int mapped = 0;
 111
 112         BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
 113
 114         rmd.pfn = pfn;
 115         rmd.prot = prot;
 116         /*
 117          * We use the err_ptr to indicate if there we are doing a contiguous
 118          * mapping or a discontigious mapping.
 119          */
 120         rmd.contiguous = !err_ptr;
 121         rmd.no_translate = no_translate;
 122
 123         while (nr) {
 124                 int index = 0;
 125                 int done = 0;
 126                 int batch = min(REMAP_BATCH_SIZE, nr);
 127                 int batch_left = batch;
 128                 range = (unsigned long)batch << PAGE_SHIFT;
 129
 130                 rmd.mmu_update = mmu_update;
 131                 err = apply_to_page_range(vma->vm_mm, addr, range,
 132                                           remap_area_pfn_pte_fn, &rmd);
 133                 if (err)
 134                         goto out;
 135
 136                 /* We record the error for each page that gives an error, but
 137                  * continue mapping until the whole set is done */
 138                 do {
 139                         int i;
 140
 141                         err = HYPERVISOR_mmu_update(&mmu_update[index],
 142                                                     batch_left, &done, domid);
 143
 144                         /*
 145                          * @err_ptr may be the same buffer as @gfn, so
 146                          * only clear it after each chunk of @gfn is
 147                          * used.
 148                          */
 149                         if (err_ptr) {
 150                                 for (i = index; i < index + done; i++)
 151                                         err_ptr[i] = 0;
 152                         }
 153                         if (err < 0) {
 154                                 if (!err_ptr)
 155                                         goto out;
 156                                 err_ptr[i] = err;
 157                                 done++; /* Skip failed frame. */
 158                         } else
 159                                 mapped += done;
 160                         batch_left -= done;
 161                         index += done;
 162                 } while (batch_left);
 163
 164                 nr -= batch;
 165                 addr += range;
 166                 if (err_ptr)
 167                         err_ptr += batch;
 168                 cond_resched();
 169         }
 170 out:
 171
 172         xen_flush_tlb_all();
 173
 174         return err < 0 ? err : mapped;
 175 }
 176
 177 int xen_remap_domain_gfn_range(struct vm_area_struct *vma,
 178                                unsigned long addr,
 179                                xen_pfn_t gfn, int nr,
 180                                pgprot_t prot, unsigned domid,
 181                                struct page **pages)
 182 {
 183         if (xen_feature(XENFEAT_auto_translated_physmap))
 184                 return -EOPNOTSUPP;
 185
 186         return do_remap_pfn(vma, addr, &gfn, nr, NULL, prot, domid, false,
 187                             pages);
 188 }
 189 EXPORT_SYMBOL_GPL(xen_remap_domain_gfn_range);
 190
 191 int xen_remap_domain_gfn_array(struct vm_area_struct *vma,
 192                                unsigned long addr,
 193                                xen_pfn_t *gfn, int nr,
 194                                int *err_ptr, pgprot_t prot,
 195                                unsigned domid, struct page **pages)
 196 {
 197         if (xen_feature(XENFEAT_auto_translated_physmap))
 198                 return xen_xlate_remap_gfn_array(vma, addr, gfn, nr, err_ptr,
 199                                                  prot, domid, pages);
 200
 201         /* We BUG_ON because it's a programmer error to pass a NULL err_ptr,
 202          * and the consequences later is quite hard to detect what the actual
 203          * cause of "wrong memory was mapped in".
 204          */
 205         BUG_ON(err_ptr == NULL);
 206         return do_remap_pfn(vma, addr, gfn, nr, err_ptr, prot, domid,
 207                             false, pages);
 208 }
 209 EXPORT_SYMBOL_GPL(xen_remap_domain_gfn_array);
 210
 211 int xen_remap_domain_mfn_array(struct vm_area_struct *vma,
 212                                unsigned long addr,
 213                                xen_pfn_t *mfn, int nr,
 214                                int *err_ptr, pgprot_t prot,
 215                                unsigned int domid, struct page **pages)
 216 {
 217         if (xen_feature(XENFEAT_auto_translated_physmap))
 218                 return -EOPNOTSUPP;
 219
 220         return do_remap_pfn(vma, addr, mfn, nr, err_ptr, prot, domid,
 221                             true, pages);
 222 }
 223 EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_array);
 224
 225 /* Returns: 0 success */
 226 int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
 227                                int nr, struct page **pages)
 228 {
 229         if (xen_feature(XENFEAT_auto_translated_physmap))
 230                 return xen_xlate_unmap_gfn_range(vma, nr, pages);
 231
 232         if (!pages)
 233                 return 0;
 234
 235         return -EINVAL;
 236 }
 237 EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range);