Re: [PATCH 6/7] target/i386: Add new CPU model EmeraldRapids

[Xiaoyao Li]

On 6/26/2023 8:56 PM, Igor Mammedov wrote:
> On Fri, 16 Jun 2023 11:23:10 +0800
> Tao Su<tao1.su@linux.intel.com>  wrote:
>
> > From: Qian Wen<qian.wen@intel.com>
> >
> > Emerald Rapids (EMR) is the next generation of Xeon server processor
> > after Sapphire Rapids (SPR).
> >
> > Currently, regarding the feature set that can be exposed to guest, there
> > isn't any one new comparing with SPR cpu model, except that EMR has a
> > different model number.
> >
> > Though it's practicable to define EMR as an alias of a new version of
> > SPR by only updating the model number and model name, it loses the
> > flexibility when new version of EMR cpu model are needed for adding new
> > features (that hasn't virtalized/supported by KVM yet).
> Which begs a question, why do we need EMR model (or alias) at all
> if it's the same as SPR at the moment.
>
> Make new features supported 1st and only then introduce a new CPU model.

Even if no new feature (that can be virtualized and exposed to guest) in 
EMR compared to SPR in the end, I think it still makes sense to provide 
a dedicated EMR CPU model in QEMU. Because
1) User will know EMR, Intel's next generation of Xeon after SRP, is 
supported by QEMU, via -cpu ?/ -cpu help;
2) It's convenient for user to create an EMR VM. People may not care 
that much what the difference between "-cpu SapphireRapids" with "-cpu 
EmeraldRapids", while they do want to create an VM which shows the CPU 
is EmeraldRapids.