Re: [PATCH v5 02/10] accel: Introduce 'query-accels' QMP command

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 5/5/21 9:07 AM, Markus Armbruster wrote:
> Philippe Mathieu-Daudé <philmd@redhat.com> writes:
> 
>> Introduce the 'query-accels' QMP command which returns a list
>> of built-in accelerator names.
>>
>> - Accelerator is a QAPI enum of all existing accelerators,
>>
>> - AcceleratorInfo is a QAPI structure providing accelerator
>>   specific information. Currently the common structure base
>>   provides the name of the accelerator, while the specific
>>   part is empty, but each accelerator can expand it.
>>
>> - 'query-accels' QMP command returns a list of @AcceleratorInfo
>>
>> For example on a KVM-only build we get:
>>
>>     { "execute": "query-accels" }
>>     {
>>         "return": [
>>             {
>>                 "name": "qtest"
>>             },
>>             {
>>                 "name": "kvm"
>>             }
>>         ]
>>     }
>>
>> Note that we can't make the enum values or union branches conditional
>> because of target-specific poisoning of accelerator definitions.
> 
> Let me try to complete this argument;
> 
>   If we did, enum Accelerator could only be used in target-specific
>   code.  But we want to use it in generic code, too.
> 
> Which generic code exactly?


cpu.c:133:#ifdef CONFIG_TCG
hmp-commands-info.hx:271:#if defined(CONFIG_TCG)
monitor/misc.c:324:#ifdef CONFIG_TCG
softmmu/physmem.c:28:#ifdef CONFIG_TCG

and more importantly:

include/exec/cpu-all.h:430:#ifdef CONFIG_TCG
include/exec/cpu-defs.h:77:#if !defined(CONFIG_USER_ONLY) &&
defined(CONFIG_TCG)
include/exec/exec-all.h:25:#ifdef CONFIG_TCG
include/sysemu/cpu-timers.h:27:#ifdef CONFIG_TCG

Thomas might provide more cases, IIRC he audited this recently.