[v4,2/9] KVM MMU: don't write-protect if have new mapping to unsync page

Commit Message

Xiao Guangrong May 6, 2010, 9:30 a.m. UTC

None

Patch

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 72238ec..1dbb96e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1333,7 +1333,7 @@  static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
 	unsigned index;
 	unsigned quadrant;
 	struct hlist_head *bucket;
-	struct kvm_mmu_page *sp;
+	struct kvm_mmu_page *sp, *unsync_sp = NULL;
 	struct hlist_node *node, *tmp;
 
 	role = vcpu->arch.mmu.base_role;
@@ -1352,20 +1352,30 @@  static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
 	hlist_for_each_entry_safe(sp, node, tmp, bucket, hash_link)
 		if (sp->gfn == gfn) {
 			if (sp->unsync)
-				if (kvm_sync_page(vcpu, sp))
-					continue;
+				unsync_sp = sp;
 
 			if (sp->role.word != role.word)
 				continue;
 
+			if (!direct && unsync_sp &&
+			      kvm_sync_page_transient(vcpu, unsync_sp)) {
+				unsync_sp = NULL;
+				break;
+			}
+
 			mmu_page_add_parent_pte(vcpu, sp, parent_pte);
 			if (sp->unsync_children) {
 				set_bit(KVM_REQ_MMU_SYNC, &vcpu->requests);
 				kvm_mmu_mark_parents_unsync(sp);
-			}
+			} else if (sp->unsync)
+				kvm_mmu_mark_parents_unsync(sp);
+
 			trace_kvm_mmu_get_page(sp, false);
 			return sp;
 		}
+	if (!direct && unsync_sp)
+		kvm_sync_page(vcpu, unsync_sp);
+
 	++vcpu->kvm->stat.mmu_cache_miss;
 	sp = kvm_mmu_alloc_page(vcpu, parent_pte);
 	if (!sp)