Re: [PATCH for-6.0 1/6] qapi: Add query-accel command

[Kevin Wolf]

Am 18.11.2020 um 09:36 hat Markus Armbruster geschrieben:
> >> >>                                       [...]  Even better would be
> >> >> returning an array of KvmInfo with information on all supported
> >> >> accelerators at once, rather than making the user call this command once
> >> >> per name.
> >> >
> >> > Maybe.  It would save us the work of answering the question
> >> > above, but is this (querying information for all accelerators at
> >> > once) going to be a common use case?
> >> 
> >> I recommend to scratch the query-accel parameter, and return information
> >> on all accelerators in this build of QEMU.  Simple, and consistent with
> >> similar ad hoc queries.  If a client is interested in just one, fishing
> >> it out of the list is easy enough.
> >> 
> >
> > Works for me. I'll then leave KvmInfo as is and will introduce AccelInfo
> > with two fields: name and enabled. enabled will be true only for
> > currently active accelerator.
> 
> Please document that at most on result can have 'enabled': true.

This doesn't feel right.

If I understand right, the proposal is to get a result like this:

    [ { 'name': 'kvm', 'enabled': true },
      { 'name': 'tcg', 'enabled': false },
      { 'name': 'xen', 'enabled': false } ]

The condition that only one field can be enabled would only be in the
documentation instead of being enforced.

Instead, consider a response like this:

    { 'available': [ 'kvm', 'tcg', 'xen' ],
      'active': 'kvm' }

This is not only shorter, but also makes sure that only one accelerator
can be reported as active.

Kevin