Re: [PATCH v5 09/26] KVM: VMX: nVMX: Support TSC scaling and PERF_GLOBAL_CTRL with enlightened VMCS

[Vitaly Kuznetsov <vkuznets@redhat.com>]

Sean Christopherson <seanjc@google.com> writes:

> On Tue, Aug 02, 2022, Vitaly Kuznetsov wrote:
>> diff --git a/arch/x86/kvm/vmx/evmcs.h b/arch/x86/kvm/vmx/evmcs.h
>> index f886a8ff0342..4b809c79ae63 100644
>> --- a/arch/x86/kvm/vmx/evmcs.h
>> +++ b/arch/x86/kvm/vmx/evmcs.h
>> @@ -37,16 +37,9 @@ DECLARE_STATIC_KEY_FALSE(enable_evmcs);
>>   *	EPTP_LIST_ADDRESS               = 0x00002024,
>>   *	VMREAD_BITMAP                   = 0x00002026,
>>   *	VMWRITE_BITMAP                  = 0x00002028,
>> - *
>> - *	TSC_MULTIPLIER                  = 0x00002032,
>>   *	PLE_GAP                         = 0x00004020,
>>   *	PLE_WINDOW                      = 0x00004022,
>>   *	VMX_PREEMPTION_TIMER_VALUE      = 0x0000482E,
>> - *      GUEST_IA32_PERF_GLOBAL_CTRL     = 0x00002808,
>> - *      HOST_IA32_PERF_GLOBAL_CTRL      = 0x00002c04,
>> - *
>> - * Currently unsupported in KVM:
>> - *	GUEST_IA32_RTIT_CTL		= 0x00002814,
>
> Almost forgot: is deleting this chunk of the comment intentional?
>

Intentional or not (I forgot :-), GUEST_IA32_RTIT_CTL is supported/used
by KVM since

commit f99e3daf94ff35dd4a878d32ff66e1fd35223ad6
Author: Chao Peng <chao.p.peng@linux.intel.com>
Date:   Wed Oct 24 16:05:10 2018 +0800

    KVM: x86: Add Intel PT virtualization work mode

...
 
commit bf8c55d8dc094c85a3f98cd302a4dddb720dd63f
Author: Chao Peng <chao.p.peng@linux.intel.com>
Date:   Wed Oct 24 16:05:14 2018 +0800

    KVM: x86: Implement Intel PT MSRs read/write emulation

but there's no corresponding field in eVMCS. It would probably be better
to remove "Currently unsupported in KVM:" line leaving

"GUEST_IA32_RTIT_CTL             = 0x00002814" 

in place. 

-- 
Vitaly