[v2,4/6] KVM: MMU: don't atomicly set spte if it's not present

Commit Message

Xiao Guangrong July 16, 2010, 3:27 a.m. UTC

None

Patch

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index b3896bf..4123e8e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -307,9 +307,10 @@  static void update_spte(u64 *sptep, u64 new_spte)
 {
 	u64 old_spte;
 
-	if (!shadow_accessed_mask || (new_spte & shadow_accessed_mask)) {
+	if (!shadow_accessed_mask || (new_spte & shadow_accessed_mask) ||
+	      !is_rmap_spte(*sptep))
 		__set_spte(sptep, new_spte);
-	} else {
+	else {
 		old_spte = __xchg_spte(sptep, new_spte);
 		if (old_spte & shadow_accessed_mask)
 			mark_page_accessed(pfn_to_page(spte_to_pfn(old_spte)));