Re: [Xen-devel] [PATCH] VMX: fix PAT value seen by guest

["Liu, Jinsong" <jinsong.liu@xxxxxxxxx>]

Reviewed-by: Liu Jinsong <jinsong.liu@xxxxxxxxx>

BTW, today is my last wroking day at Intel, so this is my last email from 
Intel's email box.
I will still in Xen community, but for this thread please cc my personal email 
'liu-j-s@xxxxxxx' -- until I use new email box from Ali Cloud of Alibaba.

Thanks,
Jinsong

Jan Beulich wrote:
> The XSA-60 fixes introduced a window during which the guest PAT gets
> forced to all zeros. This shouldn't be visible to the guest. Therefore
> we need to intercept PAT MSR accesses during that time period.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> 
> --- a/xen/arch/x86/hvm/vmx/vmx.c
> +++ b/xen/arch/x86/hvm/vmx/vmx.c
> @@ -1033,6 +1033,8 @@ static void vmx_handle_cd(struct vcpu *v
> 
>              vmx_get_guest_pat(v, pat);
>              vmx_set_guest_pat(v, uc_pat);
> +            vmx_enable_intercept_for_msr(v, MSR_IA32_CR_PAT,
> +                                         MSR_TYPE_R | MSR_TYPE_W);
> 
>              wbinvd();               /* flush possibly polluted cache
>              */ hvm_asid_flush_vcpu(v); /* invalidate memory type
> cached in TLB */ @@ -1042,6 +1044,9 @@ static void
>          vmx_handle_cd(struct vcpu *v {
>              v->arch.hvm_vcpu.cache_mode = NORMAL_CACHE_MODE;
>              vmx_set_guest_pat(v, *pat);
> +            if ( !iommu_enabled || iommu_snoop )
> +                vmx_disable_intercept_for_msr(v, MSR_IA32_CR_PAT,
> +                                              MSR_TYPE_R |
>              MSR_TYPE_W); hvm_asid_flush_vcpu(v); /* no need to flush
>          cache */ }
>      }


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