Re: [Xen-devel] [PATCH 03/15] x86/cpu/vpmu: Add Hygon Dhyana support for vPMU

[Pu Wen <puwen@xxxxxxxx>]

On 2018/12/20 22:25, Boris Ostrovsky wrote:
...
>> diff --git a/xen/arch/x86/cpu/vpmu_amd.c b/xen/arch/x86/cpu/vpmu_amd.c
>> index 5efc39b..e9f0a5c 100644
>> --- a/xen/arch/x86/cpu/vpmu_amd.c
>> +++ b/xen/arch/x86/cpu/vpmu_amd.c
>> @@ -554,6 +554,8 @@ int __init amd_vpmu_init(void)
>>       case 0x12:
>>       case 0x14:
>>       case 0x16:
>> +    case 0x17:
>> +    case 0x18:
>
>
> This also enables VPMU support for Zen which goes beyond what the
> commit message claims to do.

Sorry for the not clear commit message. Will add modification description
in the commit message and make the changes complete.

On the other hand, since current Xen vPMU still not support Zen. so in
this patch we enable 0x17 support. If this modification is not preferred,
will remove AMD Xen 0x17 support in next version.

>
> Also, why are you choosing to use legacy MSRs (and you did the same in
> Linux)? Doesn't Zen (which you are saying is similar to Hygon) support
> c001_020X bank?

In Linux, the Xen PMU driver use the default branch cases, which also use
the legacy MSRs way. So we choose to follow legacy MSRs here in Dhyana
cases.

Since both of Zen and Dhyana support C001_020X MSRs. If use the C001_020X
is preferred, we will try to modify the related codes and create a patch.
Also the Linux Xen PMU driver may need to be updated to use these MSRs.

-- 
Regards,
Pu Wen

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel