If have new mapping to the unsync page(i.e, add a new parent), just
update the page from sp->gfn but not write-protect gfn, and if need
create new shadow page form sp->gfn, we should sync it
Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 27 +++++++++++++++++++--------
1 files changed, 19 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index fd027a6..8607a64 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1196,16 +1196,20 @@ static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp);
-static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
+static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
+ bool clear_unsync)
{
if (sp->role.cr4_pae != !!is_pae(vcpu)) {
kvm_mmu_zap_page(vcpu->kvm, sp);
return 1;
}
- if (rmap_write_protect(vcpu->kvm, sp->gfn))
- kvm_flush_remote_tlbs(vcpu->kvm);
- kvm_unlink_unsync_page(vcpu->kvm, sp);
+ if (clear_unsync) {
+ if (rmap_write_protect(vcpu->kvm, sp->gfn))
+ kvm_flush_remote_tlbs(vcpu->kvm);
+ kvm_unlink_unsync_page(vcpu->kvm, sp);
+ }
+
if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
kvm_mmu_zap_page(vcpu->kvm, sp);
return 1;
@@ -1293,7 +1297,7 @@ static void mmu_sync_children(struct kvm_vcpu *vcpu,
kvm_flush_remote_tlbs(vcpu->kvm);
for_each_sp(pages, sp, parents, i) {
- kvm_sync_page(vcpu, sp);
+ kvm_sync_page(vcpu, sp, true);
mmu_pages_clear_parents(&parents);
}
cond_resched_lock(&vcpu->kvm->mmu_lock);
@@ -1313,7 +1317,7 @@ 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;
@@ -1332,12 +1336,16 @@ 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 (unsync_sp && kvm_sync_page(vcpu, unsync_sp, false)) {
+ unsync_sp = NULL;
+ continue;
+ }
+
mmu_page_add_parent_pte(vcpu, sp, parent_pte);
if (sp->unsync_children) {
set_bit(KVM_REQ_MMU_SYNC, &vcpu->requests);
@@ -1346,6 +1354,9 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
trace_kvm_mmu_get_page(sp, false);
return sp;
}
+ if (unsync_sp)
+ kvm_sync_page(vcpu, unsync_sp, true);
+
++vcpu->kvm->stat.mmu_cache_miss;
sp = kvm_mmu_alloc_page(vcpu, parent_pte);
if (!sp)
--
1.6.1.2
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