KVM: x86: Keep MSR_IA32_XSS unchanged for INIT

[PATCH] KVM: x86: Keep MSR_IA32_XSS unchanged for INIT

Posted by Xiaoyao Li 4 years, 5 months ago

It has been corrected from SDM version 075 that MSR_IA32_XSS is reset to
zero on Power up and Reset but keeps unchanged on INIT.

Fixes: a554d207dc46 ("KVM: X86: Processor States following Reset or INIT")
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
 arch/x86/kvm/x86.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 55518b7d3b96..c0727939684e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11257,6 +11257,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 		vcpu->arch.msr_misc_features_enables = 0;
 
 		vcpu->arch.xcr0 = XFEATURE_MASK_FP;
+		vcpu->arch.ia32_xss = 0;
 	}
 
 	/* All GPRs except RDX (handled below) are zeroed on RESET/INIT. */
@@ -11273,8 +11274,6 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 	cpuid_0x1 = kvm_find_cpuid_entry(vcpu, 1, 0);
 	kvm_rdx_write(vcpu, cpuid_0x1 ? cpuid_0x1->eax : 0x600);
 
-	vcpu->arch.ia32_xss = 0;
-
 	static_call(kvm_x86_vcpu_reset)(vcpu, init_event);
 
 	kvm_set_rflags(vcpu, X86_EFLAGS_FIXED);
-- 
2.27.0

Re: [PATCH] KVM: x86: Keep MSR_IA32_XSS unchanged for INIT

Posted by Paolo Bonzini 4 years, 5 months ago

On 1/26/22 04:47, Xiaoyao Li wrote:
> It has been corrected from SDM version 075 that MSR_IA32_XSS is reset to
> zero on Power up and Reset but keeps unchanged on INIT.
> 
> Fixes: a554d207dc46 ("KVM: X86: Processor States following Reset or INIT")
> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> ---
>   arch/x86/kvm/x86.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 55518b7d3b96..c0727939684e 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -11257,6 +11257,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
>   		vcpu->arch.msr_misc_features_enables = 0;
>   
>   		vcpu->arch.xcr0 = XFEATURE_MASK_FP;
> +		vcpu->arch.ia32_xss = 0;
>   	}
>   
>   	/* All GPRs except RDX (handled below) are zeroed on RESET/INIT. */
> @@ -11273,8 +11274,6 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
>   	cpuid_0x1 = kvm_find_cpuid_entry(vcpu, 1, 0);
>   	kvm_rdx_write(vcpu, cpuid_0x1 ? cpuid_0x1->eax : 0x600);
>   
> -	vcpu->arch.ia32_xss = 0;
> -
>   	static_call(kvm_x86_vcpu_reset)(vcpu, init_event);
>   
>   	kvm_set_rflags(vcpu, X86_EFLAGS_FIXED);

Queued, thanks.

Paolo