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From: Oliver Upton <oliver.upton@linux.dev>
To: Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	kvmarm@lists.linux.dev, kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 4/6] KVM: arm64: Don't serialize if the access flag isn't set
Date: Fri,  2 Dec 2022 18:51:54 +0000	[thread overview]
Message-ID: <20221202185156.696189-5-oliver.upton@linux.dev> (raw)
In-Reply-To: <20221202185156.696189-1-oliver.upton@linux.dev>

Of course, if the PTE wasn't changed then there are absolutely no
serialization requirements. Skip the DSB for an unsuccessful update to
the access flag.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
 arch/arm64/kvm/hyp/pgtable.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 204e59e05674..aa36d896bd8c 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1116,10 +1116,14 @@ int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
 kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)
 {
 	kvm_pte_t pte = 0;
-	stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
-				 &pte, NULL,
-				 KVM_PGTABLE_WALK_HANDLE_FAULT);
-	dsb(ishst);
+	int ret;
+
+	ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
+				       &pte, NULL,
+				       KVM_PGTABLE_WALK_HANDLE_FAULT);
+	if (!ret)
+		dsb(ishst);
+
 	return pte;
 }
 
-- 
2.39.0.rc0.267.gcb52ba06e7-goog

_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

WARNING: multiple messages have this Message-ID (diff)
From: Oliver Upton <oliver.upton@linux.dev>
To: Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
	kvmarm@lists.linux.dev, Ricardo Koller <ricarkol@google.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 4/6] KVM: arm64: Don't serialize if the access flag isn't set
Date: Fri,  2 Dec 2022 18:51:54 +0000	[thread overview]
Message-ID: <20221202185156.696189-5-oliver.upton@linux.dev> (raw)
Message-ID: <20221202185154.8zYvezdZaEn1wl_8s0YhjXlurLUd9cJrEfoaSdEaTVo@z> (raw)
In-Reply-To: <20221202185156.696189-1-oliver.upton@linux.dev>

Of course, if the PTE wasn't changed then there are absolutely no
serialization requirements. Skip the DSB for an unsuccessful update to
the access flag.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
 arch/arm64/kvm/hyp/pgtable.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 204e59e05674..aa36d896bd8c 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1116,10 +1116,14 @@ int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
 kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)
 {
 	kvm_pte_t pte = 0;
-	stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
-				 &pte, NULL,
-				 KVM_PGTABLE_WALK_HANDLE_FAULT);
-	dsb(ishst);
+	int ret;
+
+	ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
+				       &pte, NULL,
+				       KVM_PGTABLE_WALK_HANDLE_FAULT);
+	if (!ret)
+		dsb(ishst);
+
 	return pte;
 }
 
-- 
2.39.0.rc0.267.gcb52ba06e7-goog


WARNING: multiple messages have this Message-ID (diff)
From: Oliver Upton <oliver.upton@linux.dev>
To: Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
	kvmarm@lists.linux.dev, Ricardo Koller <ricarkol@google.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 4/6] KVM: arm64: Don't serialize if the access flag isn't set
Date: Fri,  2 Dec 2022 18:51:54 +0000	[thread overview]
Message-ID: <20221202185156.696189-5-oliver.upton@linux.dev> (raw)
In-Reply-To: <20221202185156.696189-1-oliver.upton@linux.dev>

Of course, if the PTE wasn't changed then there are absolutely no
serialization requirements. Skip the DSB for an unsuccessful update to
the access flag.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
 arch/arm64/kvm/hyp/pgtable.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 204e59e05674..aa36d896bd8c 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1116,10 +1116,14 @@ int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
 kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)
 {
 	kvm_pte_t pte = 0;
-	stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
-				 &pte, NULL,
-				 KVM_PGTABLE_WALK_HANDLE_FAULT);
-	dsb(ishst);
+	int ret;
+
+	ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
+				       &pte, NULL,
+				       KVM_PGTABLE_WALK_HANDLE_FAULT);
+	if (!ret)
+		dsb(ishst);
+
 	return pte;
 }
 
-- 
2.39.0.rc0.267.gcb52ba06e7-goog


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2022-12-02 18:52 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-02 18:51 [PATCH v2 0/6] KVM: arm64: Parallel access faults Oliver Upton
2022-12-02 18:51 ` Oliver Upton
2022-12-02 18:51 ` Oliver Upton
2022-12-02 18:51 ` [PATCH v2 1/6] KVM: arm64: Use KVM's pte type/helpers in handle_access_fault() Oliver Upton
2022-12-02 18:51   ` Oliver Upton
2022-12-02 18:51   ` Oliver Upton
2022-12-02 18:51 ` [PATCH v2 2/6] KVM: arm64: Ignore EAGAIN for walks outside of a fault Oliver Upton
2022-12-02 18:51   ` Oliver Upton
2022-12-02 18:51   ` Oliver Upton
2022-12-02 18:51 ` [PATCH v2 3/6] KVM: arm64: Return EAGAIN for invalid PTE in attr walker Oliver Upton
2022-12-02 18:51   ` Oliver Upton
2022-12-02 18:51   ` Oliver Upton
2022-12-02 18:51 ` Oliver Upton [this message]
2022-12-02 18:51   ` [PATCH v2 4/6] KVM: arm64: Don't serialize if the access flag isn't set Oliver Upton
2022-12-02 18:51   ` Oliver Upton
2022-12-02 18:51 ` [PATCH v2 5/6] KVM: arm64: Handle access faults behind the read lock Oliver Upton
2022-12-02 18:51   ` Oliver Upton
2022-12-02 18:51   ` Oliver Upton
2022-12-02 18:51 ` [PATCH v2 6/6] KVM: arm64: Condition HW AF updates on config option Oliver Upton
2022-12-02 18:51   ` Oliver Upton
2022-12-02 18:51   ` Oliver Upton
2023-01-23 20:29 ` [PATCH v2 0/6] KVM: arm64: Parallel access faults Oliver Upton
2023-01-23 20:29   ` Oliver Upton

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