From: Lai Jiangshan <jiangshanlai@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Lai Jiangshan <jiangshan.ljs@antgroup.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
kvm@vger.kernel.org
Subject: [PATCH V3 14/14] kvm: x86/mmu: Skip calling mmu->sync_spte() when the spte is 0
Date: Fri, 17 Feb 2023 07:53:21 +0800 [thread overview]
Message-ID: <20230216235321.735214-5-jiangshanlai@gmail.com> (raw)
In-Reply-To: <20230216235321.735214-1-jiangshanlai@gmail.com>
From: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Sync the spte only when the spte is set and avoid the indirect branch.
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
---
arch/x86/kvm/mmu/mmu.c | 4 ++--
arch/x86/kvm/mmu/paging_tmpl.h | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index a8ac37d51287..cd8c38463c97 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1942,7 +1942,7 @@ static int __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
return -1;
for (i = 0; i < SPTE_ENT_PER_PAGE; i++) {
- int ret = vcpu->arch.mmu->sync_spte(vcpu, sp, i);
+ int ret = sp->spt[i] ? vcpu->arch.mmu->sync_spte(vcpu, sp, i) : 0;
if (ret < -1)
return -1;
@@ -5764,7 +5764,7 @@ static void __kvm_mmu_invalidate_addr(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu
for_each_shadow_entry_using_root(vcpu, root_hpa, addr, iterator) {
struct kvm_mmu_page *sp = sptep_to_sp(iterator.sptep);
- if (sp->unsync) {
+ if (sp->unsync && *iterator.sptep) {
/*
* Get the gfn beforehand for later flushing.
* Although mmu->sync_spte() doesn't change it, but just
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index e04950015dc4..3373d6705634 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -933,7 +933,7 @@ static int FNAME(sync_spte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, int
gpa_t pte_gpa;
gfn_t gfn;
- if (!sp->spt[i])
+ if (WARN_ON_ONCE(!sp->spt[i]))
return 0;
first_pte_gpa = FNAME(get_level1_sp_gpa)(sp);
--
2.19.1.6.gb485710b
next prev parent reply other threads:[~2023-02-16 23:52 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-16 15:41 [PATCH V3 00/14] kvm: x86/mmu: Share the same code to invalidate each vTLB entry Lai Jiangshan
2023-02-16 15:41 ` [PATCH V3 01/14] KVM: x86/mmu: Use 64-bit address to invalidate to fix a subtle bug Lai Jiangshan
2023-02-16 15:41 ` [PATCH V3 02/14] kvm: x86/mmu: Move the check in FNAME(sync_page) as kvm_sync_page_check() Lai Jiangshan
2023-02-16 15:41 ` [PATCH V3 03/14] kvm: x86/mmu: Check mmu->sync_page pointer in kvm_sync_page_check() Lai Jiangshan
2023-02-16 15:41 ` [PATCH V3 04/14] kvm: x86/mmu: Set mmu->sync_page as NULL for direct paging Lai Jiangshan
2023-02-16 15:41 ` [PATCH V3 05/14] kvm: x86/mmu: Move the code out of FNAME(sync_page)'s loop body into mmu.c Lai Jiangshan
2023-02-16 15:41 ` [PATCH V3 06/14] kvm: x86/mmu: Reduce the update to the spte in FNAME(sync_spte) Lai Jiangshan
2023-02-16 15:41 ` [PATCH V3 07/14] KVM: x86/mmu: Sanity check input to kvm_mmu_free_roots() Lai Jiangshan
2023-02-16 15:41 ` [PATCH V3 08/14] kvm: x86/mmu: Use KVM_MMU_ROOT_XXX for kvm_mmu_invalidate_addr() Lai Jiangshan
2023-02-16 15:41 ` [PATCH V3 09/14] kvm: x86/mmu: Use kvm_mmu_invalidate_addr() in kvm_mmu_invpcid_gva() Lai Jiangshan
2023-02-16 23:53 ` [PATCH V3 10/14] kvm: x86/mmu: Use kvm_mmu_invalidate_addr() in nested_ept_invalidate_addr() Lai Jiangshan
2023-02-16 23:53 ` [PATCH V3 11/14] kvm: x86/mmu: Allow the roots to be invalid in FNAME(invlpg) Lai Jiangshan
2023-02-16 23:53 ` [PATCH V3 12/14] kvm: x86/mmu: Remove FNAME(invlpg) and use FNAME(sync_spte) to update vTLB instead Lai Jiangshan
2023-02-16 23:53 ` [PATCH V3 13/14] kvm: x86/mmu: Remove @no_dirty_log from FNAME(prefetch_gpte) Lai Jiangshan
2023-02-16 23:53 ` Lai Jiangshan [this message]
2023-03-23 22:50 ` [PATCH V3 00/14] kvm: x86/mmu: Share the same code to invalidate each vTLB entry Sean Christopherson
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