lkml.org 
[lkml]   [2020]   [Jun]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] KVM: arm64: kvm_reset_vcpu() return code incorrect with SVE
Date
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>
---
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..f1057603b756 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
\
 
 \ /
  Last update: 2020-06-17 12:44    [W:0.031 / U:0.484 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site