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From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org, Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Qais Yousef <qais.yousef@arm.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Quentin Perret <qperret@google.com>,
	kernel-team@android.com
Subject: [PATCH v2 3/6] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched EL0 support
Date: Mon,  9 Nov 2020 21:30:19 +0000	[thread overview]
Message-ID: <20201109213023.15092-4-will@kernel.org> (raw)
In-Reply-To: <20201109213023.15092-1-will@kernel.org>

If a vCPU tries to run 32-bit code on a system with mismatched support
at EL0, then we should kill it.

Signed-off-by: Will Deacon <will@kernel.org>
---
 arch/arm64/kvm/arm.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 5750ec34960e..d322ac0f4a8e 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -633,6 +633,15 @@ static void check_vcpu_requests(struct kvm_vcpu *vcpu)
 	}
 }
 
+static bool vcpu_mode_is_bad_32bit(struct kvm_vcpu *vcpu)
+{
+	if (likely(!vcpu_mode_is_32bit(vcpu)))
+		return false;
+
+	return !system_supports_32bit_el0() ||
+		static_branch_unlikely(&arm64_mismatched_32bit_el0);
+}
+
 /**
  * kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute guest code
  * @vcpu:	The VCPU pointer
@@ -816,7 +825,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 		 * with the asymmetric AArch32 case), return to userspace with
 		 * a fatal error.
 		 */
-		if (!system_supports_32bit_el0() && vcpu_mode_is_32bit(vcpu)) {
+		if (vcpu_mode_is_bad_32bit(vcpu)) {
 			/*
 			 * As we have caught the guest red-handed, decide that
 			 * it isn't fit for purpose anymore by making the vcpu
-- 
2.29.2.222.g5d2a92d10f8-goog


WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
	kernel-team@android.com, Quentin Perret <qperret@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Qais Yousef <qais.yousef@arm.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Will Deacon <will@kernel.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>
Subject: [PATCH v2 3/6] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched EL0 support
Date: Mon,  9 Nov 2020 21:30:19 +0000	[thread overview]
Message-ID: <20201109213023.15092-4-will@kernel.org> (raw)
In-Reply-To: <20201109213023.15092-1-will@kernel.org>

If a vCPU tries to run 32-bit code on a system with mismatched support
at EL0, then we should kill it.

Signed-off-by: Will Deacon <will@kernel.org>
---
 arch/arm64/kvm/arm.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 5750ec34960e..d322ac0f4a8e 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -633,6 +633,15 @@ static void check_vcpu_requests(struct kvm_vcpu *vcpu)
 	}
 }
 
+static bool vcpu_mode_is_bad_32bit(struct kvm_vcpu *vcpu)
+{
+	if (likely(!vcpu_mode_is_32bit(vcpu)))
+		return false;
+
+	return !system_supports_32bit_el0() ||
+		static_branch_unlikely(&arm64_mismatched_32bit_el0);
+}
+
 /**
  * kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute guest code
  * @vcpu:	The VCPU pointer
@@ -816,7 +825,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 		 * with the asymmetric AArch32 case), return to userspace with
 		 * a fatal error.
 		 */
-		if (!system_supports_32bit_el0() && vcpu_mode_is_32bit(vcpu)) {
+		if (vcpu_mode_is_bad_32bit(vcpu)) {
 			/*
 			 * As we have caught the guest red-handed, decide that
 			 * it isn't fit for purpose anymore by making the vcpu
-- 
2.29.2.222.g5d2a92d10f8-goog


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  parent reply	other threads:[~2020-11-09 21:30 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-09 21:30 [PATCH v2 0/6] An alternative series for asymmetric AArch32 systems Will Deacon
2020-11-09 21:30 ` Will Deacon
2020-11-09 21:30 ` [PATCH v2 1/6] arm64: cpuinfo: Split AArch32 registers out into a separate struct Will Deacon
2020-11-09 21:30   ` Will Deacon
2020-11-09 21:30 ` [PATCH v2 2/6] arm64: Allow mismatched 32-bit EL0 support Will Deacon
2020-11-09 21:30   ` Will Deacon
2020-11-11 19:10   ` Catalin Marinas
2020-11-11 19:10     ` Catalin Marinas
2020-11-13  9:36     ` Will Deacon
2020-11-13  9:36       ` Will Deacon
2020-11-13 10:26       ` Catalin Marinas
2020-11-13 10:26         ` Catalin Marinas
2020-11-09 21:30 ` Will Deacon [this message]
2020-11-09 21:30   ` [PATCH v2 3/6] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched " Will Deacon
2020-11-10  9:33   ` Marc Zyngier
2020-11-10  9:33     ` Marc Zyngier
2020-11-09 21:30 ` [PATCH v2 4/6] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Will Deacon
2020-11-09 21:30   ` Will Deacon
2020-11-09 21:30 ` [PATCH v2 5/6] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Will Deacon
2020-11-09 21:30   ` Will Deacon
2020-11-10  7:04   ` Greg Kroah-Hartman
2020-11-10  7:04     ` Greg Kroah-Hartman
2020-11-10  9:28     ` Catalin Marinas
2020-11-10  9:28       ` Catalin Marinas
2020-11-10  9:36       ` Greg Kroah-Hartman
2020-11-10  9:36         ` Greg Kroah-Hartman
2020-11-10  9:53         ` Marc Zyngier
2020-11-10  9:53           ` Marc Zyngier
2020-11-10 10:10           ` Greg Kroah-Hartman
2020-11-10 10:10             ` Greg Kroah-Hartman
2020-11-10 10:46             ` Marc Zyngier
2020-11-10 10:46               ` Marc Zyngier
2020-11-10 10:57         ` Catalin Marinas
2020-11-10 10:57           ` Catalin Marinas
2020-11-09 21:30 ` [PATCH v2 6/6] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon
2020-11-09 21:30   ` Will Deacon

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