KVM: MMU: split kvm_sync_page() function

Split kvm_sync_page() into kvm_sync_page() and kvm_sync_page_transient()
to clarify the code address Avi's suggestion

kvm_sync_page_transient() function only update shadow page but not mark
it sync and not write protect sp->gfn. it will be used by later patch

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 25 insertions, 4 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 5c9d6df0113e..ef5d140a2705 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1199,16 +1199,20 @@ 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;
@@ -1218,6 +1222,23 @@ static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
         return 0;
 }
 
+static void mmu_convert_notrap(struct kvm_mmu_page *sp);
+static int kvm_sync_page_transient(struct kvm_vcpu *vcpu,
+                                   struct kvm_mmu_page *sp)
+{
+        int ret;
+
+        ret = __kvm_sync_page(vcpu, sp, false);
+        if (!ret)
+                mmu_convert_notrap(sp);
+        return ret;
+}
+
+static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
+{
+        return __kvm_sync_page(vcpu, sp, true);
+}
+
 struct mmu_page_path {
         struct kvm_mmu_page *parent[PT64_ROOT_LEVEL-1];
         unsigned int idx[PT64_ROOT_LEVEL-1];