KVM: MMU: remove mmu_seq verification on pte update path

The mmu_seq verification can be removed since we get the pfn in the
protection of mmu_lock.

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

3 files changed, 7 insertions, 15 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f7dfd6479d02..ecdc562ea3e2 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -274,7 +274,7 @@ 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 22fae7593ee7..28418054b880 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 c6397795d865..74f8567d57ac 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