KVM: MMU: Split gfn_to_rmap() into two functions
rmap_write_protect() calls gfn_to_rmap() for each level with gfn fixed.
This results in calling gfn_to_memslot() repeatedly with that gfn.
This patch introduces __gfn_to_rmap() which takes the slot as an
argument to avoid this.
This is also needed for the following dirty logging optimization.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 973f254..fa71085 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -958,21 +958,27 @@
}
}
+static unsigned long *__gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level,
+ struct kvm_memory_slot *slot)
+{
+ struct kvm_lpage_info *linfo;
+
+ if (likely(level == PT_PAGE_TABLE_LEVEL))
+ return &slot->rmap[gfn - slot->base_gfn];
+
+ linfo = lpage_info_slot(gfn, slot, level);
+ return &linfo->rmap_pde;
+}
+
/*
* Take gfn and return the reverse mapping to it.
*/
static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level)
{
struct kvm_memory_slot *slot;
- struct kvm_lpage_info *linfo;
slot = gfn_to_memslot(kvm, gfn);
- if (likely(level == PT_PAGE_TABLE_LEVEL))
- return &slot->rmap[gfn - slot->base_gfn];
-
- linfo = lpage_info_slot(gfn, slot, level);
-
- return &linfo->rmap_pde;
+ return __gfn_to_rmap(kvm, gfn, level, slot);
}
static bool rmap_can_add(struct kvm_vcpu *vcpu)
@@ -1019,12 +1025,14 @@
static int rmap_write_protect(struct kvm *kvm, u64 gfn)
{
+ struct kvm_memory_slot *slot;
unsigned long *rmapp;
u64 *spte;
int i, write_protected = 0;
- rmapp = gfn_to_rmap(kvm, gfn, PT_PAGE_TABLE_LEVEL);
+ slot = gfn_to_memslot(kvm, gfn);
+ rmapp = __gfn_to_rmap(kvm, gfn, PT_PAGE_TABLE_LEVEL, slot);
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
BUG_ON(!(*spte & PT_PRESENT_MASK));
@@ -1039,7 +1047,7 @@
/* check for huge page mappings */
for (i = PT_DIRECTORY_LEVEL;
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
- rmapp = gfn_to_rmap(kvm, gfn, i);
+ rmapp = __gfn_to_rmap(kvm, gfn, i, slot);
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
BUG_ON(!(*spte & PT_PRESENT_MASK));
