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

[Markus Armbruster]

Philippe Mathieu-Daudé <philmd@redhat.com> writes:

> On 3/16/21 10:02 AM, Philippe Mathieu-Daudé wrote:
>> On 3/16/21 7:51 AM, Markus Armbruster wrote:
>>> Eric Blake <eblake@redhat.com> writes:
>>>
>>>> On 3/11/21 5:11 PM, Philippe Mathieu-Daudé wrote:
>>> [...]
>>>>> diff --git a/accel/accel-qmp.c b/accel/accel-qmp.c
>>>>> new file mode 100644
>>>>> index 00000000000..f16e49b8956
>>>>> --- /dev/null
>>>>> +++ b/accel/accel-qmp.c
>>>>> @@ -0,0 +1,47 @@
>>>>> +/*
>>>>> + * QEMU accelerators, QMP commands
>>>>> + *
>>>>> + * Copyright (c) 2021 Red Hat Inc.
>>>>> + *
>>>>> + * SPDX-License-Identifier: GPL-2.0-or-later
>>>>> + */
>>>>> +
>>>>> +#include "qemu/osdep.h"
>>>>> +#include "qapi/qapi-commands-machine.h"
>>>>> +
>>>>> +static const Accelerator accel_list[] = {
>>>>> +    ACCELERATOR_QTEST,
>>>>> +#ifdef CONFIG_TCG
>>>>> +    ACCELERATOR_TCG,
>>>>> +#endif
>>>>> +#ifdef CONFIG_KVM
>>>>> +    ACCELERATOR_KVM,
>>>>> +#endif
>>>>
>>>> ...would it be worth compiling the enum to only list enum values that
>>>> were actually compiled in?  That would change it to:
>>>>
>>>> { 'enum': 'Accelerator',
>>>>   'data': [ 'qtest',
>>>>             { 'name': 'tcg', 'if': 'defined(CONFIG_TCG)' },
>>>> ...
>> 
>> These accelerator definitions are supposed to be poisoned in generic
>> code... But I like the simplicity of your suggestion, so I'll give it
>> a try and see what happens with removing the poisoned definitions.
>
> This is actually quite interesting :) Accelerator definitions are
> declared in config-target.h, but acceleration is host specific...
>
> We certainly don't want to make qapi target-specific.

We certainly don't want to make all the generated QAPI headers
target-specific.

We have made *selected* QAPI sub-modules target-specific, namely the
ones ending with "-target", currently qapi/machine-target.json and
qapi/misc-target.json.  Only these may use poisoned symbols in 'if'
conditions.  Example:

    { 'command': 'query-sev', 'returns': 'SevInfo',
      'if': 'defined(TARGET_I386)' }