[PATCH 1/6] ARM: kvm: psci: fix handling of unimplemented functions

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From: Lorenzo Pieralisi <lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>
To: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Lorenzo Pieralisi
	<lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>,
	Christoffer Dall
	<christoffer.dall-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Anup Patel <anup.patel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Marc Zyngier <marc.zyngier-5wv7dgnIgG8@public.gmane.org>,
	Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>,
	Sudeep Holla <sudeep.holla-5wv7dgnIgG8@public.gmane.org>,
	Catalin Marinas <catalin.marinas-5wv7dgnIgG8@public.gmane.org>,
	Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>
Subject: [PATCH 1/6] ARM: kvm: psci: fix handling of unimplemented functions
Date: Fri, 29 May 2015 13:16:34 +0100	[thread overview]
Message-ID: <1432901799-18359-2-git-send-email-lorenzo.pieralisi@arm.com> (raw)
In-Reply-To: <1432901799-18359-1-git-send-email-lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>

According to the PSCI specification and the SMC/HVC calling
convention, PSCI function_ids that are not implemented must
return NOT_SUPPORTED as return value.

Current KVM implementation takes an unhandled PSCI function_id
as an error and injects an undefined instruction into the guest
if PSCI implementation is called with a function_id that is not
handled by the resident PSCI version (ie it is not implemented),
which is not the behaviour expected by a guest when calling a
PSCI function_id that is not implemented.

This patch fixes this issue by returning NOT_SUPPORTED whenever
the kvm PSCI call is executed for a function_id that is not
implemented by the PSCI kvm layer.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>
Reported-by: Sudeep Holla <sudeep.holla-5wv7dgnIgG8@public.gmane.org>
Cc: Christoffer Dall <christoffer.dall-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: Anup Patel <anup.patel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: Marc Zyngier <marc.zyngier-5wv7dgnIgG8@public.gmane.org>
---
 arch/arm/kvm/psci.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
index 7e9398c..ec5943b 100644
--- a/arch/arm/kvm/psci.c
+++ b/arch/arm/kvm/psci.c
@@ -273,7 +273,8 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
 		ret = 0;
 		break;
 	default:
-		return -EINVAL;
+		val = PSCI_RET_NOT_SUPPORTED;
+		break;
 	}
 
 	*vcpu_reg(vcpu, 0) = val;
@@ -295,10 +296,9 @@ static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
 		break;
 	case KVM_PSCI_FN_CPU_SUSPEND:
 	case KVM_PSCI_FN_MIGRATE:
+	default:
 		val = PSCI_RET_NOT_SUPPORTED;
 		break;
-	default:
-		return -EINVAL;
 	}
 
 	*vcpu_reg(vcpu, 0) = val;
-- 
2.2.1

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WARNING: multiple messages have this Message-ID (diff)

From: lorenzo.pieralisi@arm.com (Lorenzo Pieralisi)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/6] ARM: kvm: psci: fix handling of unimplemented functions
Date: Fri, 29 May 2015 13:16:34 +0100	[thread overview]
Message-ID: <1432901799-18359-2-git-send-email-lorenzo.pieralisi@arm.com> (raw)
In-Reply-To: <1432901799-18359-1-git-send-email-lorenzo.pieralisi@arm.com>

According to the PSCI specification and the SMC/HVC calling
convention, PSCI function_ids that are not implemented must
return NOT_SUPPORTED as return value.

Current KVM implementation takes an unhandled PSCI function_id
as an error and injects an undefined instruction into the guest
if PSCI implementation is called with a function_id that is not
handled by the resident PSCI version (ie it is not implemented),
which is not the behaviour expected by a guest when calling a
PSCI function_id that is not implemented.

This patch fixes this issue by returning NOT_SUPPORTED whenever
the kvm PSCI call is executed for a function_id that is not
implemented by the PSCI kvm layer.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reported-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Anup Patel <anup.patel@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kvm/psci.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
index 7e9398c..ec5943b 100644
--- a/arch/arm/kvm/psci.c
+++ b/arch/arm/kvm/psci.c
@@ -273,7 +273,8 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
 		ret = 0;
 		break;
 	default:
-		return -EINVAL;
+		val = PSCI_RET_NOT_SUPPORTED;
+		break;
 	}

 	*vcpu_reg(vcpu, 0) = val;
@@ -295,10 +296,9 @@ static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
 		break;
 	case KVM_PSCI_FN_CPU_SUSPEND:
 	case KVM_PSCI_FN_MIGRATE:
+	default:
 		val = PSCI_RET_NOT_SUPPORTED;
 		break;
-	default:
-		return -EINVAL;
 	}

 	*vcpu_reg(vcpu, 0) = val;
-- 
2.2.1

next prev parent reply	other threads:[~2015-05-29 12:16 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-29 12:16 [PATCH 0/6] drivers: firmware: psci: add basic v1.0 support Lorenzo Pieralisi
2015-05-29 12:16 ` Lorenzo Pieralisi
     [not found] ` <1432901799-18359-1-git-send-email-lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>
2015-05-29 12:16   ` Lorenzo Pieralisi [this message]
2015-05-29 12:16     ` [PATCH 1/6] ARM: kvm: psci: fix handling of unimplemented functions Lorenzo Pieralisi
     [not found]     ` <1432901799-18359-2-git-send-email-lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>
2015-05-29 13:04       ` Sudeep Holla
2015-05-29 13:04         ` Sudeep Holla
2015-06-09 17:18       ` Marc Zyngier
2015-06-09 17:18         ` Marc Zyngier
     [not found]         ` <55771FDC.3090800-5wv7dgnIgG8@public.gmane.org>
2015-06-10  8:24           ` Lorenzo Pieralisi
2015-06-10  8:24             ` Lorenzo Pieralisi
2015-05-29 12:16   ` [PATCH 2/6] drivers: firmware: psci: add INVALID_ADDRESS return value Lorenzo Pieralisi
2015-05-29 12:16     ` Lorenzo Pieralisi
2015-05-29 12:16   ` [PATCH 3/6] drivers: firmware: psci: move power_state handling to generic code Lorenzo Pieralisi
2015-05-29 12:16     ` Lorenzo Pieralisi
     [not found]     ` <1432901799-18359-4-git-send-email-lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>
2015-06-01  9:28       ` Will Deacon
2015-06-01  9:28         ` Will Deacon
2015-05-29 12:16   ` [PATCH 4/6] drivers: firmware: psci: add PSCI_FEATURES call Lorenzo Pieralisi
2015-05-29 12:16     ` Lorenzo Pieralisi
2015-05-29 12:16   ` [PATCH 5/6] drivers: firmware: psci: add extended stateid power_state support Lorenzo Pieralisi
2015-05-29 12:16     ` Lorenzo Pieralisi
     [not found]     ` <1432901799-18359-6-git-send-email-lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>
2015-06-05 14:16       ` Ashwin Chaugule
2015-06-05 14:16         ` Ashwin Chaugule
     [not found]         ` <CAJ5Y-eYLAjOcTU1Md3Rmc0E49A5Dby1aoBzwtpKpD4Rg=XAYfA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-06-08 11:03           ` Lorenzo Pieralisi
2015-06-08 11:03             ` Lorenzo Pieralisi
2015-05-29 12:16   ` [PATCH 6/6] drivers: firmware: psci: add PSCI v1.0 DT bindings Lorenzo Pieralisi
2015-05-29 12:16     ` Lorenzo Pieralisi

find likely ancestor, descendant, or conflicting patches for this message:
( dfblob:7e9398c dfblob:ec5943b dfblob:7e9398c dfblob:ec5943b )
 OR (
bs:"[PATCH 1/6] ARM: kvm: psci: fix handling of unimplemented functions" )
	(help)

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