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From: David Matlack <dmatlack@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
	Borislav Petkov <bp@suse.de>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Damien Le Moal <damien.lemoal@opensource.wdc.com>,
	kvm@vger.kernel.org, David Matlack <dmatlack@google.com>
Subject: [PATCH 3/9] KVM: x86/mmu: Consolidate mmu_seq calculations in kvm_faultin_pfn()
Date: Mon, 15 Aug 2022 16:01:04 -0700	[thread overview]
Message-ID: <20220815230110.2266741-4-dmatlack@google.com> (raw)
In-Reply-To: <20220815230110.2266741-1-dmatlack@google.com>

Calculate mmu_seq during kvm_faultin_pfn() and stash it in struct
kvm_page_fault. The eliminates duplicate code and reduces the amount of
parameters needed for is_page_fault_stale().

Note, the smp_rmb() needs a comment but that is out of scope for this
commit which is pure code motion.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
---
 arch/x86/kvm/mmu/mmu.c          | 14 ++++++--------
 arch/x86/kvm/mmu/mmu_internal.h |  1 +
 arch/x86/kvm/mmu/paging_tmpl.h  |  6 +-----
 3 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 8c293a88d923..af1b7e7fb4fb 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4127,6 +4127,9 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 	struct kvm_memory_slot *slot = fault->slot;
 	bool async;
 
+	fault->mmu_seq = vcpu->kvm->mmu_notifier_seq;
+	smp_rmb();
+
 	/*
 	 * Retry the page fault if the gfn hit a memslot that is being deleted
 	 * or moved.  This ensures any existing SPTEs for the old memslot will
@@ -4183,7 +4186,7 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
  * root was invalidated by a memslot update or a relevant mmu_notifier fired.
  */
 static bool is_page_fault_stale(struct kvm_vcpu *vcpu,
-				struct kvm_page_fault *fault, int mmu_seq)
+				struct kvm_page_fault *fault)
 {
 	struct kvm_mmu_page *sp = to_shadow_page(vcpu->arch.mmu->root.hpa);
 
@@ -4203,14 +4206,12 @@ static bool is_page_fault_stale(struct kvm_vcpu *vcpu,
 		return true;
 
 	return fault->slot &&
-	       mmu_notifier_retry_hva(vcpu->kvm, mmu_seq, fault->hva);
+	       mmu_notifier_retry_hva(vcpu->kvm, fault->mmu_seq, fault->hva);
 }
 
 static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 {
 	bool is_tdp_mmu_fault = is_tdp_mmu(vcpu->arch.mmu);
-
-	unsigned long mmu_seq;
 	int r;
 
 	fault->gfn = fault->addr >> PAGE_SHIFT;
@@ -4227,9 +4228,6 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 	if (r)
 		return r;
 
-	mmu_seq = vcpu->kvm->mmu_notifier_seq;
-	smp_rmb();
-
 	r = kvm_faultin_pfn(vcpu, fault);
 	if (r != RET_PF_CONTINUE)
 		return r;
@@ -4245,7 +4243,7 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 	else
 		write_lock(&vcpu->kvm->mmu_lock);
 
-	if (is_page_fault_stale(vcpu, fault, mmu_seq))
+	if (is_page_fault_stale(vcpu, fault))
 		goto out_unlock;
 
 	r = make_mmu_pages_available(vcpu);
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 582def531d4d..1c0a1e7c796d 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -221,6 +221,7 @@ struct kvm_page_fault {
 	struct kvm_memory_slot *slot;
 
 	/* Outputs of kvm_faultin_pfn.  */
+	unsigned long mmu_seq;
 	kvm_pfn_t pfn;
 	hva_t hva;
 	bool map_writable;
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index f5958071220c..a199db4acecc 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -791,7 +791,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 {
 	struct guest_walker walker;
 	int r;
-	unsigned long mmu_seq;
 	bool is_self_change_mapping;
 
 	pgprintk("%s: addr %lx err %x\n", __func__, fault->addr, fault->error_code);
@@ -838,9 +837,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 	else
 		fault->max_level = walker.level;
 
-	mmu_seq = vcpu->kvm->mmu_notifier_seq;
-	smp_rmb();
-
 	r = kvm_faultin_pfn(vcpu, fault);
 	if (r != RET_PF_CONTINUE)
 		return r;
@@ -871,7 +867,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 	r = RET_PF_RETRY;
 	write_lock(&vcpu->kvm->mmu_lock);
 
-	if (is_page_fault_stale(vcpu, fault, mmu_seq))
+	if (is_page_fault_stale(vcpu, fault))
 		goto out_unlock;
 
 	r = make_mmu_pages_available(vcpu);
-- 
2.37.1.595.g718a3a8f04-goog


  parent reply	other threads:[~2022-08-16  2:39 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-15 23:01 [PATCH 0/9] KVM: x86/mmu: Always enable the TDP MMU when TDP is enabled David Matlack
2022-08-15 23:01 ` [PATCH 1/9] " David Matlack
2022-08-17 10:05   ` Paolo Bonzini
2022-08-17 16:49     ` David Matlack
2022-08-17 16:53       ` Paolo Bonzini
2022-08-17 17:46         ` David Matlack
2022-08-15 23:01 ` [PATCH 2/9] KVM: x86/mmu: Drop kvm->arch.tdp_mmu_enabled David Matlack
2022-08-24 14:21   ` kernel test robot
2022-08-15 23:01 ` David Matlack [this message]
2022-08-15 23:01 ` [PATCH 4/9] KVM: x86/mmu: Rename __direct_map() to nonpaging_map() David Matlack
2022-08-15 23:01 ` [PATCH 5/9] KVM: x86/mmu: Separate TDP and non-paging fault handling David Matlack
2022-08-24 17:06   ` kernel test robot
2022-08-15 23:01 ` [PATCH 6/9] KVM: x86/mmu: Stop needlessly making MMU pages available for TDP MMU faults David Matlack
2022-08-15 23:01 ` [PATCH 7/9] KVM: x86/mmu: Handle "error PFNs" in kvm_faultin_pfn() David Matlack
2022-08-15 23:01 ` [PATCH 8/9] KVM: x86/mmu: Avoid memslot lookup during KVM_PFN_ERR_HWPOISON handling David Matlack
2022-08-15 23:01 ` [PATCH 9/9] KVM: x86/mmu: Try to handle no-slot faults during kvm_faultin_pfn() David Matlack
2022-08-15 23:09   ` David Matlack
2022-08-16  8:16 ` [PATCH 0/9] KVM: x86/mmu: Always enable the TDP MMU when TDP is enabled Peter Zijlstra
2022-08-16 16:30   ` David Matlack
2022-08-17  8:53     ` Peter Zijlstra
2022-08-17 10:01     ` Huang, Kai
2022-08-17 16:42       ` David Matlack
2022-08-17 23:36         ` Huang, Kai
2022-08-16 22:54 ` David Matlack

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