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From: Marc Zyngier <maz@kernel.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, kernel-team@android.com,
	stable@vger.kernel.org, Steven Price <steven.price@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu
Subject: [PATCH 2/4] KVM: arm64: Fix kvm_reset_vcpu() return code being incorrect with SVE
Date: Mon, 29 Jun 2020 17:25:17 +0100
Message-ID: <20200629162519.825200-3-maz@kernel.org> (raw)
In-Reply-To: <20200629162519.825200-1-maz@kernel.org>

From: Steven Price <steven.price@arm.com>

If SVE is enabled then 'ret' can be assigned the return value of
kvm_vcpu_enable_sve() which may be 0 causing future "goto out" sites to
erroneously return 0 on failure rather than -EINVAL as expected.

Remove the initialisation of 'ret' and make setting the return value
explicit to avoid this situation in the future.

Fixes: 9a3cdf26e336 ("KVM: arm64/sve: Allow userspace to enable SVE for vcpus")
Cc: stable@vger.kernel.org
Reported-by: James Morse <james.morse@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200617105456.28245-1-steven.price@arm.com
---
 arch/arm64/kvm/reset.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index d3b209023727..6ed36be51b4b 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -245,7 +245,7 @@ static int kvm_vcpu_enable_ptrauth(struct kvm_vcpu *vcpu)
  */
 int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 {
-	int ret = -EINVAL;
+	int ret;
 	bool loaded;
 	u32 pstate;
 
@@ -269,15 +269,19 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 
 	if (test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, vcpu->arch.features) ||
 	    test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features)) {
-		if (kvm_vcpu_enable_ptrauth(vcpu))
+		if (kvm_vcpu_enable_ptrauth(vcpu)) {
+			ret = -EINVAL;
 			goto out;
+		}
 	}
 
 	switch (vcpu->arch.target) {
 	default:
 		if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
-			if (!cpus_have_const_cap(ARM64_HAS_32BIT_EL1))
+			if (!cpus_have_const_cap(ARM64_HAS_32BIT_EL1)) {
+				ret = -EINVAL;
 				goto out;
+			}
 			pstate = VCPU_RESET_PSTATE_SVC;
 		} else {
 			pstate = VCPU_RESET_PSTATE_EL1;
-- 
2.27.0

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  parent reply index

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-29 16:25 [GIT PULL] KVM/arm64 fixes for 5.8, take #2 Marc Zyngier
2020-06-29 16:25 ` [PATCH 1/4] KVM: arm64: Annotate hyp NMI-related functions as __always_inline Marc Zyngier
2020-06-29 16:25 ` Marc Zyngier [this message]
2020-06-29 16:25 ` [PATCH 3/4] KVM: arm64: pvtime: Ensure task delay accounting is enabled Marc Zyngier
2020-06-29 16:25 ` [PATCH 4/4] KVM: arm64: vgic-v4: Plug race between non-residency and v4.1 doorbell Marc Zyngier
2020-07-01 14:24 ` [GIT PULL] KVM/arm64 fixes for 5.8, take #2 Paolo Bonzini

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