lkml.org 
[lkml]   [2021]   [Dec]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v2 23/23] kvm: x86: Disable RDMSR interception of IA32_XFD_ERR
From
On 12/21/21 07:29, Liu, Jing2 wrote:
>>
> Thanks for reviewing the patches.
>
> If disable unconditionally in vmx_create_vcpu, it means even guest has
> no cpuid, the msr read is passthrough to guest and it can read a value, which
> seems strange, though spec doesn't mention the read behaviour w/o cpuid.
>
> How about disabling read interception at vmx_vcpu_after_set_cpuid?
>
> if (boot_cpu_has(X86_FEATURE_XFD) && guest_cpuid_has(vcpu, X86_FEATURE_XFD))
> vmx_set_intercept_for_msr(vcpu, MSR_IA32_XFD_ERR, MSR_TYPE_R, false);

Even better:

if (boot_cpu_has(X86_FEATURE_XFD))
vmx_set_intercept_for_msr(vcpu, MSR_IA32_XFD_ERR, MSR_TYPE_R,
!guest_cpuid_has(vcpu, X86_FEATURE_XFD));

Thanks,

Paolo

\
 
 \ /
  Last update: 2021-12-21 09:49    [W:0.064 / U:0.492 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site