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Commit 7c562522 authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Avi Kivity
Browse files

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: default avatarXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent a0c0ab2f

arch/x86/include/asm/kvm_host.h

+1 −1
Original line number Diff line number Diff line
@@ -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;

arch/x86/kvm/mmu.c

+5 −11
Original line number Diff line number Diff line
@@ -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;

arch/x86/kvm/paging_tmpl.h

+1 −3
Original line number Diff line number Diff line
@@ -325,7 +325,7 @@ static bool FNAME(prefetch_invalid_gpte)(struct kvm_vcpu *vcpu, 
}



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