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 *mfn;
  67         bool contiguous;
  68         pgprot_t prot;
  69         struct mmu_update *mmu_update;
  70 };
  71
  72 static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
  73                                  unsigned long addr, void *data)
  74 {
  75         struct remap_data *rmd = data;
  76         pte_t pte = pte_mkspecial(mfn_pte(*rmd->mfn, rmd->prot));
  77
  78         /* If we have a contiguous range, just update the mfn itself,
  79            else update pointer to be "next mfn". */
  80         if (rmd->contiguous)
  81                 (*rmd->mfn)++;
  82         else
  83                 rmd->mfn++;
  84
  85         rmd->mmu_update->ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
  86         rmd->mmu_update->val = pte_val_ma(pte);
  87         rmd->mmu_update++;
  88
  89         return 0;
  90 }
  91
  92 static int do_remap_gfn(struct vm_area_struct *vma,
  93                         unsigned long addr,
  94                         xen_pfn_t *gfn, int nr,
  95                         int *err_ptr, pgprot_t prot,
  96                         unsigned domid,
  97                         struct page **pages)
  98 {
  99         int err = 0;
 100         struct remap_data rmd;
 101         struct mmu_update mmu_update[REMAP_BATCH_SIZE];
 102         unsigned long range;
 103         int mapped = 0;
 104
 105         BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
 106
 107         rmd.mfn = gfn;
 108         rmd.prot = prot;
 109         /* We use the err_ptr to indicate if there we are doing a contiguous
 110          * mapping or a discontigious mapping. */
 111         rmd.contiguous = !err_ptr;
 112
 113         while (nr) {
 114                 int index = 0;
 115                 int done = 0;
 116                 int batch = min(REMAP_BATCH_SIZE, nr);
 117                 int batch_left = batch;
 118                 range = (unsigned long)batch << PAGE_SHIFT;
 119
 120                 rmd.mmu_update = mmu_update;
 121                 err = apply_to_page_range(vma->vm_mm, addr, range,
 122                                           remap_area_mfn_pte_fn, &rmd);
 123                 if (err)
 124                         goto out;
 125
 126                 /* We record the error for each page that gives an error, but
 127                  * continue mapping until the whole set is done */
 128                 do {
 129                         int i;
 130
 131                         err = HYPERVISOR_mmu_update(&mmu_update[index],
 132                                                     batch_left, &done, domid);
 133
 134                         /*
 135                          * @err_ptr may be the same buffer as @gfn, so
 136                          * only clear it after each chunk of @gfn is
 137                          * used.
 138                          */
 139                         if (err_ptr) {
 140                                 for (i = index; i < index + done; i++)
 141                                         err_ptr[i] = 0;
 142                         }
 143                         if (err < 0) {
 144                                 if (!err_ptr)
 145                                         goto out;
 146                                 err_ptr[i] = err;
 147                                 done++; /* Skip failed frame. */
 148                         } else
 149                                 mapped += done;
 150                         batch_left -= done;
 151                         index += done;
 152                 } while (batch_left);
 153
 154                 nr -= batch;
 155                 addr += range;
 156                 if (err_ptr)
 157                         err_ptr += batch;
 158                 cond_resched();
 159         }
 160 out:
 161
 162         xen_flush_tlb_all();
 163
 164         return err < 0 ? err : mapped;
 165 }
 166
 167 int xen_remap_domain_gfn_range(struct vm_area_struct *vma,
 168                                unsigned long addr,
 169                                xen_pfn_t gfn, int nr,
 170                                pgprot_t prot, unsigned domid,
 171                                struct page **pages)
 172 {
 173         return do_remap_gfn(vma, addr, &gfn, nr, NULL, prot, domid, pages);
 174 }
 175 EXPORT_SYMBOL_GPL(xen_remap_domain_gfn_range);
 176
 177 int xen_remap_domain_gfn_array(struct vm_area_struct *vma,
 178                                unsigned long addr,
 179                                xen_pfn_t *gfn, int nr,
 180                                int *err_ptr, pgprot_t prot,
 181                                unsigned domid, struct page **pages)
 182 {
 183         /* We BUG_ON because it's a programmer error to pass a NULL err_ptr,
 184          * and the consequences later is quite hard to detect what the actual
 185          * cause of "wrong memory was mapped in".
 186          */
 187         BUG_ON(err_ptr == NULL);
 188         return do_remap_gfn(vma, addr, gfn, nr, err_ptr, prot, domid, pages);
 189 }
 190 EXPORT_SYMBOL_GPL(xen_remap_domain_gfn_array);
 191
 192 /* Returns: 0 success */
 193 int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
 194                                int numpgs, struct page **pages)
 195 {
 196         if (!pages || !xen_feature(XENFEAT_auto_translated_physmap))
 197                 return 0;
 198
 199         return -EINVAL;
 200 }
 201 EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range);