KVM: MMU: introduce for_each_slot_rmap_range

It's used to abstract the code from kvm_handle_hva_range and it will be
used by later patch

Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index b1f5f09e0c29f41a9b25dae872b9c0cfcdd70ba7..316c432439956df46e7a3074be70693347e28934 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1412,6 +1412,74 @@ restart:
        return 0;
 }
 
+struct slot_rmap_walk_iterator {
+       /* input fields. */
+       struct kvm_memory_slot *slot;
+       gfn_t start_gfn;
+       gfn_t end_gfn;
+       int start_level;
+       int end_level;
+
+       /* output fields. */
+       gfn_t gfn;
+       unsigned long *rmap;
+       int level;
+
+       /* private field. */
+       unsigned long *end_rmap;
+};
+
+static void
+rmap_walk_init_level(struct slot_rmap_walk_iterator *iterator, int level)
+{
+       iterator->level = level;
+       iterator->gfn = iterator->start_gfn;
+       iterator->rmap = __gfn_to_rmap(iterator->gfn, level, iterator->slot);
+       iterator->end_rmap = __gfn_to_rmap(iterator->end_gfn, level,
+                                          iterator->slot);
+}
+
+static void
+slot_rmap_walk_init(struct slot_rmap_walk_iterator *iterator,
+                   struct kvm_memory_slot *slot, int start_level,
+                   int end_level, gfn_t start_gfn, gfn_t end_gfn)
+{
+       iterator->slot = slot;
+       iterator->start_level = start_level;
+       iterator->end_level = end_level;
+       iterator->start_gfn = start_gfn;
+       iterator->end_gfn = end_gfn;
+
+       rmap_walk_init_level(iterator, iterator->start_level);
+}
+
+static bool slot_rmap_walk_okay(struct slot_rmap_walk_iterator *iterator)
+{
+       return !!iterator->rmap;
+}
+
+static void slot_rmap_walk_next(struct slot_rmap_walk_iterator *iterator)
+{
+       if (++iterator->rmap <= iterator->end_rmap) {
+               iterator->gfn += (1UL << KVM_HPAGE_GFN_SHIFT(iterator->level));
+               return;
+       }
+
+       if (++iterator->level > iterator->end_level) {
+               iterator->rmap = NULL;
+               return;
+       }
+
+       rmap_walk_init_level(iterator, iterator->level);
+}
+
+#define for_each_slot_rmap_range(_slot_, _start_level_, _end_level_,   \
+          _start_gfn, _end_gfn, _iter_)                                \
+       for (slot_rmap_walk_init(_iter_, _slot_, _start_level_,         \
+                                _end_level_, _start_gfn, _end_gfn);    \
+            slot_rmap_walk_okay(_iter_);                               \
+            slot_rmap_walk_next(_iter_))
+
 static int kvm_handle_hva_range(struct kvm *kvm,
                                unsigned long start,
                                unsigned long end,
@@ -1423,10 +1491,10 @@ static int kvm_handle_hva_range(struct kvm *kvm,
                                               int level,
                                               unsigned long data))
 {
-       int j;
-       int ret = 0;
        struct kvm_memslots *slots;
        struct kvm_memory_slot *memslot;
+       struct slot_rmap_walk_iterator iterator;
+       int ret = 0;
 
        slots = kvm_memslots(kvm);
 
@@ -1446,26 +1514,11 @@ static int kvm_handle_hva_range(struct kvm *kvm,
                gfn_start = hva_to_gfn_memslot(hva_start, memslot);
                gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
 
-               for (j = PT_PAGE_TABLE_LEVEL;
-                    j <= PT_MAX_HUGEPAGE_LEVEL; ++j) {
-                       unsigned long idx, idx_end;
-                       unsigned long *rmapp;
-                       gfn_t gfn = gfn_start;
-
-                       /*
-                        * {idx(page_j) | page_j intersects with
-                        *  [hva_start, hva_end)} = {idx, idx+1, ..., idx_end}.
-                        */
-                       idx = gfn_to_index(gfn_start, memslot->base_gfn, j);
-                       idx_end = gfn_to_index(gfn_end - 1, memslot->base_gfn, j);
-
-                       rmapp = __gfn_to_rmap(gfn_start, j, memslot);
-
-                       for (; idx <= idx_end;
-                              ++idx, gfn += (1UL << KVM_HPAGE_GFN_SHIFT(j)))
-                               ret |= handler(kvm, rmapp++, memslot,
-                                              gfn, j, data);
-               }
+               for_each_slot_rmap_range(memslot, PT_PAGE_TABLE_LEVEL,
+                               PT_MAX_HUGEPAGE_LEVEL, gfn_start, gfn_end - 1,
+                               &iterator)
+                       ret |= handler(kvm, iterator.rmap, memslot,
+                                      iterator.gfn, iterator.level, data);
        }
 
        return ret;