[1/2] KVM: MMU: remove mmu_seq verification on pte write path

Commit Message

Xiao Guangrong March 28, 2011, 2:29 a.m. UTC

None

Comments

Avi Kivity April 5, 2011, 8:35 a.m. UTC | #1

On 03/28/2011 04:29 AM, Xiao Guangrong wrote:
> The mmu_seq verification can be removed since we get the pfn in the
> protection of mmu_lock

Applied, thanks.

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 35f81b1..ea9fea3 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -258,7 +258,7 @@  struct kvm_mmu {
 			 struct kvm_mmu_page *sp);
 	void (*invlpg)(struct kvm_vcpu *vcpu, gva_t gva);
 	void (*update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
-			u64 *spte, const void *pte, unsigned long mmu_seq);
+			   u64 *spte, const void *pte);
 	hpa_t root_hpa;
 	int root_level;
 	int shadow_root_level;
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 22fae75..2841805 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1206,7 +1206,7 @@  static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
 
 static void nonpaging_update_pte(struct kvm_vcpu *vcpu,
 				 struct kvm_mmu_page *sp, u64 *spte,
-				 const void *pte, unsigned long mmu_seq)
+				 const void *pte)
 {
 	WARN_ON(1);
 }
@@ -3163,9 +3163,8 @@  static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
 }
 
 static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
-				  struct kvm_mmu_page *sp,
-				  u64 *spte,
-				  const void *new, unsigned long mmu_seq)
+				  struct kvm_mmu_page *sp, u64 *spte,
+				  const void *new)
 {
 	if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
 		++vcpu->kvm->stat.mmu_pde_zapped;
@@ -3173,7 +3172,7 @@  static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
         }
 
 	++vcpu->kvm->stat.mmu_pte_updated;
-	vcpu->arch.mmu.update_pte(vcpu, sp, spte, new, mmu_seq);
+	vcpu->arch.mmu.update_pte(vcpu, sp, spte, new);
 }
 
 static bool need_remote_flush(u64 old, u64 new)
@@ -3229,7 +3228,6 @@  void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 	struct kvm_mmu_page *sp;
 	struct hlist_node *node;
 	LIST_HEAD(invalid_list);
-	unsigned long mmu_seq;
 	u64 entry, gentry, *spte;
 	unsigned pte_size, page_offset, misaligned, quadrant, offset;
 	int level, npte, invlpg_counter, r, flooded = 0;
@@ -3271,9 +3269,6 @@  void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 		break;
 	}
 
-	mmu_seq = vcpu->kvm->mmu_notifier_seq;
-	smp_rmb();
-
 	spin_lock(&vcpu->kvm->mmu_lock);
 	if (atomic_read(&vcpu->kvm->arch.invlpg_counter) != invlpg_counter)
 		gentry = 0;
@@ -3345,8 +3340,7 @@  void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 			if (gentry &&
 			      !((sp->role.word ^ vcpu->arch.mmu.base_role.word)
 			      & mask.word))
-				mmu_pte_write_new_pte(vcpu, sp, spte, &gentry,
-						      mmu_seq);
+				mmu_pte_write_new_pte(vcpu, sp, spte, &gentry);
 			if (!remote_flush && need_remote_flush(entry, *spte))
 				remote_flush = true;
 			++spte;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index c639779..74f8567 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -325,7 +325,7 @@  no_present:
 }
 
 static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
-			      u64 *spte, const void *pte, unsigned long mmu_seq)
+			      u64 *spte, const void *pte)
 {
 	pt_element_t gpte;
 	unsigned pte_access;
@@ -342,8 +342,6 @@  static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 		kvm_release_pfn_clean(pfn);
 		return;
 	}
-	if (mmu_notifier_retry(vcpu, mmu_seq))
-		return;
 
 	/*
 	 * we call mmu_set_spte() with host_writable = true because that