Re: Priority of -accel

[Thomas Huth <thuth@redhat.com>]

On 08/01/2020 14.24, Paolo Bonzini wrote:
> On 08/01/20 14:10, Daniel P. Berrangé wrote:
>> On Wed, Jan 08, 2020 at 01:41:59PM +0100, Paolo Bonzini wrote:
>>> On 08/01/20 11:58, Thomas Huth wrote:
>>>>> "-accel default" could be considered to have vibes of Do The Right
>>>>> Thing (tm) and could in time actually become so!
>>>>
>>>> "-accel default" sounds like the default behavior that you'd also get if
>>>> you don't use this option at all ... what about "-accel auto" to say
>>>> that QEMU should pick an accelerator automatically?
>>>
>>> Questions to answer before thinking about the name: how would it
>>> co-operate with other "-accel" options?  how would you pass sub-options
>>> to the accelerators?
>>
>> If people don't have a preference for a specific accelerator, just need
>> "a working accelerator", then I think it is reasonable to assume they
>> won't want/need to pass options to the accelerators either.
>>
>> "-accel default" is targetting the simple "do the right thing" use
>> case, so IMHO doesn't need to support per-accelerator options.
> 
> So basically the idea is to add an option that means "ignore every other
> -accel option and act as if we had "-accel kvm -accel tcg"?  That seems
> like a hack to me, especially since you can achieve the same effect with
> a binary named qemu-kvm and no -accel options at all.

But we could disallow multiple "-accel" options in that case (or just
always use the last in the list), so we don't have to deal with
priorities of the options here at all... Well, not sure whether that's
really really better than what we currently have, so maybe we should
just keep it in the current shape...

 Thomas