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From: Marc Zyngier <maz@kernel.org>
To: kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org
Cc: Eric Auger <eric.auger@redhat.com>,
	Ricardo Koller <ricarkol@google.com>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Oliver Upton <oupton@google.com>,
	kernel-team@android.com
Subject: [PATCH v2 3/3] KVM: arm64: Warn if accessing timer pending state outside of vcpu context
Date: Tue,  7 Jun 2022 14:14:27 +0100	[thread overview]
Message-ID: <20220607131427.1164881-4-maz@kernel.org> (raw)
In-Reply-To: <20220607131427.1164881-1-maz@kernel.org>

A recurrent bug in the KVM/arm64 code base consists in trying to
access the timer pending state outside of the vcpu context, which
makes zero sense (the pending state only exists when the vcpu
is loaded).

In order to avoid more embarassing crashes and catch the offenders
red-handed, add a warning to kvm_arch_timer_get_input_level() and
return the state as non-pending. This avoids taking the system down,
and still helps tracking down silly bugs.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/arch_timer.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 4e39ace073af..3b8d062e30ea 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -1230,6 +1230,9 @@ bool kvm_arch_timer_get_input_level(int vintid)
 	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
 	struct arch_timer_context *timer;
 
+	if (WARN(!vcpu, "No vcpu context!\n"))
+		return false;
+
 	if (vintid == vcpu_vtimer(vcpu)->irq.irq)
 		timer = vcpu_vtimer(vcpu);
 	else if (vintid == vcpu_ptimer(vcpu)->irq.irq)
-- 
2.34.1


WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org
Cc: kernel-team@android.com
Subject: [PATCH v2 3/3] KVM: arm64: Warn if accessing timer pending state outside of vcpu context
Date: Tue,  7 Jun 2022 14:14:27 +0100	[thread overview]
Message-ID: <20220607131427.1164881-4-maz@kernel.org> (raw)
In-Reply-To: <20220607131427.1164881-1-maz@kernel.org>

A recurrent bug in the KVM/arm64 code base consists in trying to
access the timer pending state outside of the vcpu context, which
makes zero sense (the pending state only exists when the vcpu
is loaded).

In order to avoid more embarassing crashes and catch the offenders
red-handed, add a warning to kvm_arch_timer_get_input_level() and
return the state as non-pending. This avoids taking the system down,
and still helps tracking down silly bugs.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/arch_timer.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 4e39ace073af..3b8d062e30ea 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -1230,6 +1230,9 @@ bool kvm_arch_timer_get_input_level(int vintid)
 	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
 	struct arch_timer_context *timer;
 
+	if (WARN(!vcpu, "No vcpu context!\n"))
+		return false;
+
 	if (vintid == vcpu_vtimer(vcpu)->irq.irq)
 		timer = vcpu_vtimer(vcpu);
 	else if (vintid == vcpu_ptimer(vcpu)->irq.irq)
-- 
2.34.1

_______________________________________________
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: Marc Zyngier <maz@kernel.org>
To: kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org
Cc: Eric Auger <eric.auger@redhat.com>,
	Ricardo Koller <ricarkol@google.com>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Oliver Upton <oupton@google.com>,
	kernel-team@android.com
Subject: [PATCH v2 3/3] KVM: arm64: Warn if accessing timer pending state outside of vcpu context
Date: Tue,  7 Jun 2022 14:14:27 +0100	[thread overview]
Message-ID: <20220607131427.1164881-4-maz@kernel.org> (raw)
In-Reply-To: <20220607131427.1164881-1-maz@kernel.org>

A recurrent bug in the KVM/arm64 code base consists in trying to
access the timer pending state outside of the vcpu context, which
makes zero sense (the pending state only exists when the vcpu
is loaded).

In order to avoid more embarassing crashes and catch the offenders
red-handed, add a warning to kvm_arch_timer_get_input_level() and
return the state as non-pending. This avoids taking the system down,
and still helps tracking down silly bugs.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/arch_timer.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 4e39ace073af..3b8d062e30ea 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -1230,6 +1230,9 @@ bool kvm_arch_timer_get_input_level(int vintid)
 	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
 	struct arch_timer_context *timer;
 
+	if (WARN(!vcpu, "No vcpu context!\n"))
+		return false;
+
 	if (vintid == vcpu_vtimer(vcpu)->irq.irq)
 		timer = vcpu_vtimer(vcpu);
 	else if (vintid == vcpu_ptimer(vcpu)->irq.irq)
-- 
2.34.1


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

  parent reply	other threads:[~2022-06-07 13:14 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-07 13:14 [PATCH v2 0/3] KVM: arm64: Fix userspace access to HW pending state Marc Zyngier
2022-06-07 13:14 ` Marc Zyngier
2022-06-07 13:14 ` Marc Zyngier
2022-06-07 13:14 ` [PATCH v2 1/3] KVM: arm64: Don't read a HW interrupt pending state in user context Marc Zyngier
2022-06-07 13:14   ` Marc Zyngier
2022-06-07 13:14   ` Marc Zyngier
2022-06-07 13:14 ` [PATCH v2 2/3] KVM: arm64: Replace vgic_v3_uaccess_read_pending with vgic_uaccess_read_pending Marc Zyngier
2022-06-07 13:14   ` Marc Zyngier
2022-06-07 13:14   ` Marc Zyngier
2022-06-07 19:28   ` Eric Auger
2022-06-07 19:28     ` Eric Auger
2022-06-07 19:28     ` Eric Auger
2022-06-07 13:14 ` Marc Zyngier [this message]
2022-06-07 13:14   ` [PATCH v2 3/3] KVM: arm64: Warn if accessing timer pending state outside of vcpu context Marc Zyngier
2022-06-07 13:14   ` Marc Zyngier
2022-06-07 15:27 ` (subset) [PATCH v2 0/3] KVM: arm64: Fix userspace access to HW pending state Marc Zyngier
2022-06-07 15:27   ` Marc Zyngier
2022-06-07 15:27   ` Marc Zyngier

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