Re: [RFC PATCH v2 06/11] hw/ppc: Restrict KVM to various PPC machines

[Philippe Mathieu-Daudé]

On 2/22/21 6:59 AM, David Gibson wrote:
> On Fri, Feb 19, 2021 at 06:38:42PM +0100, Philippe Mathieu-Daudé wrote:
>> Restrit KVM to the following PPC machines:
>> - 40p
>> - bamboo
>> - g3beige
>> - mac99
>> - mpc8544ds
>> - ppce500
>> - pseries
>> - sam460ex
>> - virtex-ml507
> 
> Hrm.
> 
> The reason this list is kind of surprising is because there are 3
> different "flavours" of KVM on ppc: KVM HV ("pseries" only), KVM PR
> (almost any combination, theoretically, but kind of buggy in
> practice), and the Book E specific KVM (Book-E systems with HV
> extensions only).
> 
> But basically, qemu explicitly managing what accelerators are
> available for each machine seems the wrong way around to me.  The
> approach we've generally taken is that qemu requests the specific
> features it needs of KVM, and KVM tells us whether it can supply those
> or not (which may involve selecting between one of the several
> flavours).
> 
> That way we can extend KVM to cover more situations without needing
> corresponding changes in qemu every time.

OK thanks for the information. I'll wait the other patches
get reviewed (in particular the most important ones, 2 and
10) before respining including this information.

Regards,

Phil.