Re: [PATCH] i386: pass CLZERO to guests with EPYC CPU model on AMD ZEN platform

[Ani Sinha]

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> On Dec 18, 2019, at 5:23 PM, Paolo Bonzini <address@hidden> wrote:
> 
> On 18/12/19 10:05, Ani Sinha wrote:
>> CLZERO CPUID should be passed on to the guests that use EPYC or EPYC-IBPB CPU
>> model when the AMD ZEN based host supports it. This change makes it recognize
>> this CPUID for guests which use EPYC or EPYC-IBPB CPU model.
>> 
>> Signed-off-by: Ani Sinha <address@hidden>
>> ---
>> target/i386/cpu.c | 2 ++
>> 1 file changed, 2 insertions(+)
>> 
>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> index 69f518a..55f0691 100644
>> --- a/target/i386/cpu.c
>> +++ b/target/i386/cpu.c
>> @@ -3813,6 +3813,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
>>             CPUID_EXT3_MISALIGNSSE | CPUID_EXT3_SSE4A | CPUID_EXT3_ABM |
>>             CPUID_EXT3_CR8LEG | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM |
>>             CPUID_EXT3_TOPOEXT,
>> +        .features[FEAT_8000_0008_EBX] =
>> +            CPUID_8000_0008_EBX_CLZERO,
>>         .features[FEAT_7_0_EBX] =
>>             CPUID_7_0_EBX_FSGSBASE | CPUID_7_0_EBX_BMI1 | CPUID_7_0_EBX_AVX2 
>> |
>>             CPUID_7_0_EBX_SMEP | CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_RDSEED |
>> 
> 
> This needs to be done only for newer machine type (or is it CPU model
> versions now? need Eduardo to respond).
> 
> Paolo