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From: Oliver Upton <oupton@google.com>
To: kvmarm@lists.cs.columbia.edu
Cc: kvm@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
	James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Peter Shier <pshier@google.com>,
	Ricardo Koller <ricarkol@google.com>,
	Reiji Watanabe <reijiw@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Will Deacon <will@kernel.org>, Oliver Upton <oupton@google.com>,
	Andrew Jones <drjones@redhat.com>
Subject: [PATCH v2 1/3] KVM: arm64: Generally disallow SMC64 for AArch32 guests
Date: Tue, 22 Mar 2022 18:35:36 +0000	[thread overview]
Message-ID: <20220322183538.2757758-2-oupton@google.com> (raw)
In-Reply-To: <20220322183538.2757758-1-oupton@google.com>

The only valid calling SMC calling convention from an AArch32 state is
SMC32. Disallow any PSCI function that sets the SMC64 function ID bit
when called from AArch32 rather than comparing against known SMC64 PSCI
functions.

Note that without this change KVM advertises the SMC64 flavor of
SYSTEM_RESET2 to AArch32 guests.

Fixes: d43583b890e7 ("KVM: arm64: Expose PSCI SYSTEM_RESET2 call to the guest")
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Reiji Watanabe <reijiw@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Oliver Upton <oupton@google.com>
---
 arch/arm64/kvm/psci.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
index a433c3eac9b7..cd3ee947485f 100644
--- a/arch/arm64/kvm/psci.c
+++ b/arch/arm64/kvm/psci.c
@@ -216,15 +216,11 @@ static void kvm_psci_narrow_to_32bit(struct kvm_vcpu *vcpu)
 
 static unsigned long kvm_psci_check_allowed_function(struct kvm_vcpu *vcpu, u32 fn)
 {
-	switch(fn) {
-	case PSCI_0_2_FN64_CPU_SUSPEND:
-	case PSCI_0_2_FN64_CPU_ON:
-	case PSCI_0_2_FN64_AFFINITY_INFO:
-		/* Disallow these functions for 32bit guests */
-		if (vcpu_mode_is_32bit(vcpu))
-			return PSCI_RET_NOT_SUPPORTED;
-		break;
-	}
+	/*
+	 * Prevent 32 bit guests from calling 64 bit PSCI functions.
+	 */
+	if ((fn & PSCI_0_2_64BIT) && vcpu_mode_is_32bit(vcpu))
+		return PSCI_RET_NOT_SUPPORTED;
 
 	return 0;
 }
-- 
2.35.1.894.gb6a874cedc-goog


WARNING: multiple messages have this Message-ID (diff)
From: Oliver Upton <oupton@google.com>
To: kvmarm@lists.cs.columbia.edu
Cc: kvm@vger.kernel.org, Will Deacon <will@kernel.org>,
	Marc Zyngier <maz@kernel.org>, Peter Shier <pshier@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/3] KVM: arm64: Generally disallow SMC64 for AArch32 guests
Date: Tue, 22 Mar 2022 18:35:36 +0000	[thread overview]
Message-ID: <20220322183538.2757758-2-oupton@google.com> (raw)
In-Reply-To: <20220322183538.2757758-1-oupton@google.com>

The only valid calling SMC calling convention from an AArch32 state is
SMC32. Disallow any PSCI function that sets the SMC64 function ID bit
when called from AArch32 rather than comparing against known SMC64 PSCI
functions.

Note that without this change KVM advertises the SMC64 flavor of
SYSTEM_RESET2 to AArch32 guests.

Fixes: d43583b890e7 ("KVM: arm64: Expose PSCI SYSTEM_RESET2 call to the guest")
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Reiji Watanabe <reijiw@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Oliver Upton <oupton@google.com>
---
 arch/arm64/kvm/psci.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
index a433c3eac9b7..cd3ee947485f 100644
--- a/arch/arm64/kvm/psci.c
+++ b/arch/arm64/kvm/psci.c
@@ -216,15 +216,11 @@ static void kvm_psci_narrow_to_32bit(struct kvm_vcpu *vcpu)
 
 static unsigned long kvm_psci_check_allowed_function(struct kvm_vcpu *vcpu, u32 fn)
 {
-	switch(fn) {
-	case PSCI_0_2_FN64_CPU_SUSPEND:
-	case PSCI_0_2_FN64_CPU_ON:
-	case PSCI_0_2_FN64_AFFINITY_INFO:
-		/* Disallow these functions for 32bit guests */
-		if (vcpu_mode_is_32bit(vcpu))
-			return PSCI_RET_NOT_SUPPORTED;
-		break;
-	}
+	/*
+	 * Prevent 32 bit guests from calling 64 bit PSCI functions.
+	 */
+	if ((fn & PSCI_0_2_64BIT) && vcpu_mode_is_32bit(vcpu))
+		return PSCI_RET_NOT_SUPPORTED;
 
 	return 0;
 }
-- 
2.35.1.894.gb6a874cedc-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 <oupton@google.com>
To: kvmarm@lists.cs.columbia.edu
Cc: kvm@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
	James Morse <james.morse@arm.com>,
	 Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	 linux-arm-kernel@lists.infradead.org,
	Peter Shier <pshier@google.com>,
	 Ricardo Koller <ricarkol@google.com>,
	Reiji Watanabe <reijiw@google.com>,
	 Paolo Bonzini <pbonzini@redhat.com>,
	Will Deacon <will@kernel.org>, Oliver Upton <oupton@google.com>,
	Andrew Jones <drjones@redhat.com>
Subject: [PATCH v2 1/3] KVM: arm64: Generally disallow SMC64 for AArch32 guests
Date: Tue, 22 Mar 2022 18:35:36 +0000	[thread overview]
Message-ID: <20220322183538.2757758-2-oupton@google.com> (raw)
In-Reply-To: <20220322183538.2757758-1-oupton@google.com>

The only valid calling SMC calling convention from an AArch32 state is
SMC32. Disallow any PSCI function that sets the SMC64 function ID bit
when called from AArch32 rather than comparing against known SMC64 PSCI
functions.

Note that without this change KVM advertises the SMC64 flavor of
SYSTEM_RESET2 to AArch32 guests.

Fixes: d43583b890e7 ("KVM: arm64: Expose PSCI SYSTEM_RESET2 call to the guest")
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Reiji Watanabe <reijiw@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Oliver Upton <oupton@google.com>
---
 arch/arm64/kvm/psci.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
index a433c3eac9b7..cd3ee947485f 100644
--- a/arch/arm64/kvm/psci.c
+++ b/arch/arm64/kvm/psci.c
@@ -216,15 +216,11 @@ static void kvm_psci_narrow_to_32bit(struct kvm_vcpu *vcpu)
 
 static unsigned long kvm_psci_check_allowed_function(struct kvm_vcpu *vcpu, u32 fn)
 {
-	switch(fn) {
-	case PSCI_0_2_FN64_CPU_SUSPEND:
-	case PSCI_0_2_FN64_CPU_ON:
-	case PSCI_0_2_FN64_AFFINITY_INFO:
-		/* Disallow these functions for 32bit guests */
-		if (vcpu_mode_is_32bit(vcpu))
-			return PSCI_RET_NOT_SUPPORTED;
-		break;
-	}
+	/*
+	 * Prevent 32 bit guests from calling 64 bit PSCI functions.
+	 */
+	if ((fn & PSCI_0_2_64BIT) && vcpu_mode_is_32bit(vcpu))
+		return PSCI_RET_NOT_SUPPORTED;
 
 	return 0;
 }
-- 
2.35.1.894.gb6a874cedc-goog


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

  reply	other threads:[~2022-03-22 18:35 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-22 18:35 [PATCH v2 0/3] KVM: arm64: Fixes for SMC64 SYSTEM_RESET2 calls Oliver Upton
2022-03-22 18:35 ` Oliver Upton
2022-03-22 18:35 ` Oliver Upton
2022-03-22 18:35 ` Oliver Upton [this message]
2022-03-22 18:35   ` [PATCH v2 1/3] KVM: arm64: Generally disallow SMC64 for AArch32 guests Oliver Upton
2022-03-22 18:35   ` Oliver Upton
2022-03-22 18:35 ` [PATCH v2 2/3] KVM: arm64: Actually prevent SMC64 SYSTEM_RESET2 from AArch32 Oliver Upton
2022-03-22 18:35   ` Oliver Upton
2022-03-22 18:35   ` Oliver Upton
2022-03-22 18:35 ` [PATCH v2 3/3] KVM: arm64: Drop unneeded minor version check from PSCI v1.x handler Oliver Upton
2022-03-22 18:35   ` Oliver Upton
2022-03-22 18:35   ` Oliver Upton
2022-03-23  9:26 ` [PATCH v2 0/3] KVM: arm64: Fixes for SMC64 SYSTEM_RESET2 calls Marc Zyngier
2022-03-23  9:26   ` Marc Zyngier
2022-03-23  9:26   ` Marc Zyngier

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