Re: [Qemu-devel] [PATCH RFC] i386: Add new Hygon 'Dhyana' and 'Dhyana-IBPB' CPU models

[Pu Wen]

On 2019/4/12 21:25, Daniel P. Berrangé wrote:
> On Fri, Apr 12, 2019 at 08:37:49PM +0800, Pu Wen wrote:
> > Add two new base CPU models called 'Dhyana' and 'Dhyana-IBPB' to model
> > processors from Hygon Dhyana (family 18h), which derived from AMD EPYC
> > (family 17h). 'Dhyana-IBPB' is a copy of the 'Dhyana' CPU model with
> > just CPUID_8000_0008_EBX_IBPB added.
...
> The Google results I see suggest that Dhyana CPUs started to become
> available in July 2018, so surely they would come with microcode
> that has the IBPB right from day 1 ?

Yes, you are right. Dhyana CPUs already have the IBPB feature.

> Am I missing anything that means there will be a compelling need
> to support Dhyana /without/ IBPB ?
>
> If not, then we only need 1 CPU model and that would include IBPB.

Okay, will only keep one CPU model which include IBPB by using the name 
'Dhyana'.

Thx.

--
Regards,
Pu Wen