2019-06-20 09:01:16

by Wanpeng Li

Subject: [PATCH] KVM: VMX: Raise #GP when guest read/write forbidden IA32_XSS

From: Wanpeng Li <[email protected]>

Raise #GP when guest read/write forbidden IA32_XSS.

Fixes: 203000993de5 (kvm: vmx: add MSR logic for XSAVES)
Reported-by: Xiaoyao Li <[email protected]>
Reported-by: Tao Xu <[email protected]>
Cc: Cc: Paolo Bonzini <[email protected]>
Cc: Radim Krčmář <[email protected]>
Cc: [email protected]
Signed-off-by: Wanpeng Li <[email protected]>
---
arch/x86/kvm/vmx/vmx.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b939a68..d174b62 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1732,7 +1732,10 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
return vmx_get_vmx_msr(&vmx->nested.msrs, msr_info->index,
&msr_info->data);
case MSR_IA32_XSS:
- if (!vmx_xsaves_supported())
+ if (!vmx_xsaves_supported() ||
+ (!msr_info->host_initiated &&
+ !(guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
+ guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))))
return 1;
msr_info->data = vcpu->arch.ia32_xss;
break;
@@ -1962,7 +1965,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
return 1;
return vmx_set_vmx_msr(vcpu, msr_index, data);
case MSR_IA32_XSS:
- if (!vmx_xsaves_supported())
+ if (!vmx_xsaves_supported() ||
+ (!msr_info->host_initiated &&
+ !(guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
+ guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))))
return 1;
/*
* The only supported bit as of Skylake is bit 8, but
--
2.7.4

2019-06-20 12:25:27

by Paolo Bonzini

Subject: Re: [PATCH] KVM: VMX: Raise #GP when guest read/write forbidden IA32_XSS

On 20/06/19 11:00, Wanpeng Li wrote:
> From: Wanpeng Li <[email protected]>
>
> Raise #GP when guest read/write forbidden IA32_XSS.
>
> Fixes: 203000993de5 (kvm: vmx: add MSR logic for XSAVES)
> Reported-by: Xiaoyao Li <[email protected]>
> Reported-by: Tao Xu <[email protected]>
> Cc: Cc: Paolo Bonzini <[email protected]>
> Cc: Radim Krčmář <[email protected]>
> Cc: [email protected]
> Signed-off-by: Wanpeng Li <[email protected]>

Queued, thanks.

Paolo

> ---
> arch/x86/kvm/vmx/vmx.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index b939a68..d174b62 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -1732,7 +1732,10 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> return vmx_get_vmx_msr(&vmx->nested.msrs, msr_info->index,
> &msr_info->data);
> case MSR_IA32_XSS:
> - if (!vmx_xsaves_supported())
> + if (!vmx_xsaves_supported() ||
> + (!msr_info->host_initiated &&
> + !(guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
> + guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))))
> return 1;
> msr_info->data = vcpu->arch.ia32_xss;
> break;
> @@ -1962,7 +1965,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> return 1;
> return vmx_set_vmx_msr(vcpu, msr_index, data);
> case MSR_IA32_XSS:
> - if (!vmx_xsaves_supported())
> + if (!vmx_xsaves_supported() ||
> + (!msr_info->host_initiated &&
> + !(guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
> + guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))))
> return 1;
> /*
> * The only supported bit as of Skylake is bit 8, but
> -- 2.7.4
>