KVM: Unify kvm_mmu_pre_write() and kvm_mmu_post_write()

Instead of calling two functions and repeating expensive checks, call one
function and provide it with before/after information.

Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index 2277b7c..b3a83ef 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -1118,7 +1118,7 @@
 	return r;
 }
 
-static void mmu_pre_write_zap_pte(struct kvm_vcpu *vcpu,
+static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
 				  struct kvm_mmu_page *page,
 				  u64 *spte)
 {
@@ -1137,7 +1137,8 @@
 	*spte = 0;
 }
 
-void kvm_mmu_pre_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes)
+void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
+		       const u8 *old, const u8 *new, int bytes)
 {
 	gfn_t gfn = gpa >> PAGE_SHIFT;
 	struct kvm_mmu_page *page;
@@ -1206,16 +1207,12 @@
 		spte = __va(page->page_hpa);
 		spte += page_offset / sizeof(*spte);
 		while (npte--) {
-			mmu_pre_write_zap_pte(vcpu, page, spte);
+			mmu_pte_write_zap_pte(vcpu, page, spte);
 			++spte;
 		}
 	}
 }
 
-void kvm_mmu_post_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes)
-{
-}
-
 int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
 {
 	gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva);