[PATCH 1/6] accel: Introduce 'query-accels' QMP command

[Paolo Bonzini]

On 12/03/21 10:17, Andrew Jones wrote:
> On Fri, Mar 12, 2021 at 10:01:43AM +0100, Paolo Bonzini wrote:
>> On 12/03/21 09:48, Andrew Jones wrote:
>>>> I think we definitely need the additional data section here: For KVM on
>>>> POWER, it would be good to know whether it's KVM-HV or KVM-PR, for KVM on
>>>> MIPS it would be good to know whether it's KVM_VM_MIPS_VZ or KVM_VM_MIPS_TE,
>>>> for KVM on x86 whether it's the AMD flavor or Intel, ...
>>>
>>> Could also pre-expand all of these and list them individually.
>>
>> That seems worse (in general) because in a lot of cases you don't care; the
>> basic query-accels output should match the argument to "-accel".
>>
> 
> For these special subtypes, what's the property/state that indicates it
> when just using '-accel kvm' on the command line? Because if this qmp
> list matches the '-accel' parameter list, then qtest and other qmp clients
> may need to query that other information too, in order for this accel
> query to be useful. And, do we need an accel-specific qmp query for it?
> Or, is that information already available?

It depends.

On PPC (if I remember/understand correctly) only pseries supports both 
HV and PR, while all other machines only support KVM-PR.  So in that 
case it's a kvm-type machine property that is defined only for the 
pseries machine.

On MIPS instead there's no option and VZ always wins over TE.  I think 
it could be made an option on -accel, but I'm not familiar with MIPS 
machine types.

Something like "name: 'kvm', types: ['book3s-hv', 'pr']" would work 
nicely for KVM-PPC, and likewise for MIPS.

Paolo