Re: [Qemu-devel] [PATCH v2 0/5] Removal of deprecated -no-kvm* options

[Thomas Huth <thuth@redhat.com>]

On 07.05.2018 19:01, Paolo Bonzini wrote:
> On 07/05/2018 18:50, Markus Armbruster wrote:
>> Paolo Bonzini <pbonzini@redhat.com> writes:
>>
>>> On 07/05/2018 13:56, Markus Armbruster wrote:
>>>> Adding more and more ways to do the same stuff does not improve an
>>>> interface.  Interface design needs to be *opinionated*.  If we decide
>>>> -machine accel=tcg isn't a nice interface, by all means create a better
>>>> one, but as replacement[*], not as addition.
>>>>
>>>> Furthermore:
>>>>
>>>>     tcg: add options for enabling MTTCG
>>>>
>>>>     We know there will be cases where MTTCG won't work until additional work
>>>>     is done in the front/back ends to support. It will however be useful to
>>>>     be able to turn it on.
>>>>
>>>>     As a result MTTCG will default to off unless the combination is
>>>>     supported. However the user can turn it on for the sake of testing.
>>>>
>>>>     Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
>>>>     [AJB: move to -accel tcg,thread=multi|single, defaults]
>>>>     Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>>>>     Reviewed-by: Richard Henderson <rth@twiddle.net>
>>>>
>>>> I'm sorry, but this us sub-par.  Yes, the commit is also about "enabling
>>>> MTTCG", but it also adds a new way to select accelerators, without ever
>>>> spelling that out.  It should've been split, and properly described.
>>>
>>> Perhaps we can deprecate "-M accel" then, and also while we're at it
>>> move kernel_irqchip from -machine to "-accel kvm" where it belongs?
>>
>> Sounds good to me.
> 
> Thomas, here's one for you! :)

I like the idea of deprecating "-machine accel=xxx" - but that will also
be a bigger change, since "-accel" is internally setting the accel
option of the machine again...

Also libvirt is still using "-machine accel=..." as far as I know, so
we've got to make sure that this gets changed there, too...

 Thomas