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SubjectRe: [PATCH v2 2/2] KVM: VMX: Fix VPID capability detection
2017-10-18 1:48 GMT+08:00 Paolo Bonzini <pbonzini@redhat.com>:
> On 17/10/2017 19:43, Jim Mattson wrote:
>>> + &vmx_capability.ept, &vmx_capability.vpid);
>>> +
>>> if (_cpu_based_2nd_exec_control & SECONDARY_EXEC_ENABLE_EPT) {
>>> /* CR3 accesses and invlpg don't need to cause VM Exits when EPT
>>> enabled */
>>> _cpu_based_exec_control &= ~(CPU_BASED_CR3_LOAD_EXITING |
>>> CPU_BASED_CR3_STORE_EXITING |
>>> CPU_BASED_INVLPG_EXITING);
>>> - rdmsr(MSR_IA32_VMX_EPT_VPID_CAP,
>>> - vmx_capability.ept, vmx_capability.vpid);
>>> - }
>>> + } else
>>> + vmx_capability.ept = 0;
>> I would expect vmx_capability.ept to already be 0 here. Otherwise, L0
>> is reporting inconsistent VMX capabilities.
>>
>>> + if (!(_cpu_based_2nd_exec_control & SECONDARY_EXEC_ENABLE_VPID))
>>> + vmx_capability.vpid = 0;
>> I would expect vmx_capability.vpid to already be 0 here. Otherwise, L0
>> is reporting inconsistent VMX capabilities.
>>
>
> That's true, but I think it's better to be safe. Maybe add a pr_warn if
> it is not zero?

Will do in v3.

Regards,
Wanpeng Li

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