Re: [PATCH v4 16/17] kvm: x86: Add support IA32_CORE_CAPABILITY MSR

Paolo Bonzini
2019-03-08T07:54:55Z

On 08/03/19 07:10, Xiaoyao Li wrote:
>> so that non-virtualizable features are hidden and
>>
>> if (boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT))
>> data |= CORE_CAP_SPLIT_LOCK_DETECT;
>>
>> so that userspace gets "for free" the FMS list that will be added
>> later to the kernel.
> I think it's redundant. Because there is no case that
> rdmsrl_safe(MSR_IA32_CORE_CAPABILITY, &data) shows no split lock detection while
> boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT).

There will be when the kernel will add a list of FMS values that have
split lock detection but lack the core capabilities MSR. Or at least
that is what Fenghua said in the cover letter.

Paolo