* [PATCH v2] KVM: arm64: kvm_reset_vcpu() return code incorrect with SVE
@ 2020-06-17 10:54 Steven Price
2020-06-22 13:41 ` Marc Zyngier
0 siblings, 1 reply; 2+ messages in thread
From: Steven Price @ 2020-06-17 10:54 UTC (permalink / raw)
To: Catalin Marinas, Marc Zyngier, Will Deacon
Cc: James Morse, Julien Thierry, Suzuki K Poulose, kvmarm,
linux-arm-kernel, linux-kernel, Dave Martin, Steven Price
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")
Reported-by: James Morse <james.morse@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v1:
* Fix embarrassing accidental inversion of the if() test
The problematic chunk isn't visible in the diff, so reproduced here:
if (!kvm_arm_vcpu_sve_finalized(vcpu)) {
if (test_bit(KVM_ARM_VCPU_SVE, vcpu->arch.features)) {
ret = kvm_vcpu_enable_sve(vcpu);
if (ret)
goto out;
}
} else {
kvm_vcpu_reset_sve(vcpu);
}
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;
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] KVM: arm64: kvm_reset_vcpu() return code incorrect with SVE
2020-06-17 10:54 [PATCH v2] KVM: arm64: kvm_reset_vcpu() return code incorrect with SVE Steven Price
@ 2020-06-22 13:41 ` Marc Zyngier
0 siblings, 0 replies; 2+ messages in thread
From: Marc Zyngier @ 2020-06-22 13:41 UTC (permalink / raw)
To: Alexandru Elisei, kvm, kvmarm, linux-arm-kernel, Catalin Marinas,
Steven Price, Will Deacon
Cc: james.morse, suzuki.poulose, julien.thierry.kdev, linux-kernel,
Dave Martin
On Wed, 17 Jun 2020 11:54:56 +0100, Steven Price wrote:
> 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.
Applied to next, thanks!
[1/1] KVM: arm64: Fix kvm_reset_vcpu() return code being incorrect with SVE
commit: 66b7e05dc0239c5817859f261098ba9cc2efbd2b
Cheers,
M.
--
Without deviation from the norm, progress is not possible.
^ permalink raw reply [flat|nested] 2+ messages in thread
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