On 5/9/2020 7:37 AM, Sean Christopherson wrote:
Restore a guest CPUID update that was unintentional collateral damage
when the per-vCPU guest_xstate_size field was removed.
It's really unintentional. None of us noticed it. :(
It's good that you catch it!
Cc: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
Fixes: d87277414b851 ("kvm: x86: Cleanup vcpu->arch.guest_xstate_size")
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
There's nothing more thrilling than watching bisect home in on your own
commits, only to land on someone else's on the very last step.
arch/x86/kvm/cpuid.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 35845704cf57a..cd708b0b460a0 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -84,11 +84,13 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu)
kvm_read_cr4_bits(vcpu, X86_CR4_PKE));
best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
- if (!best)
+ if (!best) {
vcpu->arch.guest_supported_xcr0 = 0;
- else
+ } else {
vcpu->arch.guest_supported_xcr0 =
(best->eax | ((u64)best->edx << 32)) & supported_xcr0;
+ best->ebx = xstate_required_size(vcpu->arch.xcr0, false);
+ }
best = kvm_find_cpuid_entry(vcpu, 0xD, 1);
if (best && (cpuid_entry_has(best, X86_FEATURE_XSAVES) ||
