From: David Stevens <stevensd@chromium.org>
To: Sean Christopherson <seanjc@google.com>
Cc: Wanpeng Li <wanpengli@tencent.com>,
kvm@vger.kernel.org, David Hildenbrand <david@redhat.com>,
linux-mips@vger.kernel.org, Paul Mackerras <paulus@ozlabs.org>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
kvmarm@lists.cs.columbia.edu,
Janosch Frank <frankja@linux.ibm.com>,
Marc Zyngier <maz@kernel.org>, Joerg Roedel <joro@8bytes.org>,
Huacai Chen <chenhuacai@kernel.org>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
kvm-ppc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
Jim Mattson <jmattson@google.com>,
Cornelia Huck <cohuck@redhat.com>,
linux-kernel@vger.kernel.org, James Morse <james.morse@arm.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>
Subject: [PATCH v3 1/2] KVM: x86/mmu: Skip mmu_notifier check when handling MMIO page fault
Date: Thu, 28 Jan 2021 15:05:14 +0900 [thread overview]
Message-ID: <20210128060515.1732758-2-stevensd@google.com> (raw)
In-Reply-To: <20210128060515.1732758-1-stevensd@google.com>
From: Sean Christopherson <seanjc@google.com>
Don't retry a page fault due to an mmu_notifier invalidation when
handling a page fault for a GPA that did not resolve to a memslot, i.e.
an MMIO page fault. Invalidations from the mmu_notifier signal a change
in a host virtual address (HVA) mapping; without a memslot, there is no
HVA and thus no possibility that the invalidation is relevant to the
page fault being handled.
Note, the MMIO vs. memslot generation checks handle the case where a
pending memslot will create a memslot overlapping the faulting GPA. The
mmu_notifier checks are orthogonal to memslot updates.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/mmu/mmu.c | 2 +-
arch/x86/kvm/mmu/paging_tmpl.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 6d16481aa29d..9ac0a727015d 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3725,7 +3725,7 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
r = RET_PF_RETRY;
spin_lock(&vcpu->kvm->mmu_lock);
- if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
+ if (!is_noslot_pfn(pfn) && mmu_notifier_retry(vcpu->kvm, mmu_seq))
goto out_unlock;
r = make_mmu_pages_available(vcpu);
if (r)
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 50e268eb8e1a..ab54263d857c 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -869,7 +869,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code,
r = RET_PF_RETRY;
spin_lock(&vcpu->kvm->mmu_lock);
- if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
+ if (!is_noslot_pfn(pfn) && mmu_notifier_retry(vcpu->kvm, mmu_seq))
goto out_unlock;
kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT);
--
2.30.0.280.ga3ce27912f-goog
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next prev parent reply other threads:[~2021-01-28 6:06 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-28 6:05 [PATCH v3 0/2] KVM: x86/mmu: Skip mmu_notifier changes when possible David Stevens
2021-01-28 6:05 ` David Stevens [this message]
2021-01-28 6:05 ` [PATCH v3 2/2] KVM: x86/mmu: Consider the hva in mmu_notifier retry David Stevens
2021-01-28 12:48 ` [PATCH v3 0/2] KVM: x86/mmu: Skip mmu_notifier changes when possible Paolo Bonzini
2021-02-05 5:58 ` David Stevens
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