[libvirt] [Qemu-devel] [PATCH 5/7] qapi: add query-cpudefs command
Anthony Liguori
aliguori at us.ibm.com
Fri Jul 27 15:01:54 UTC 2012
Peter Maydell <peter.maydell at linaro.org> writes:
> On 27 July 2012 14:37, Anthony Liguori <aliguori at us.ibm.com> wrote:
>> This command attempts to map to the behavior of -cpu ?. Unfortunately, the
>> output of this command differs wildly across targets.
>
> I've never really understood why so much of the cpu selection
> logic is deferred to target-*...
It will be fixed as part of the QOM conversion.
>> To accomodate this, we use a weak symbol to implement a default version of the
>> command that fails with a QERR_NOT_SUPPORTED error code. Targets can then
>> override and implement this command if it makes sense for them.
>
> This is a bit of a weak reason (boom boom!) for requiring a platform
> specific thing like weak symbols, though, and it's not how we handle
> similar existing cases (eg see the configure/makefile logic for
> memory_mapping.c vs memory_mapping-stub.c).
I don't think we have a consistent approach today FWIW. I think using
weak symbols is sufficiently compelling that it will become consistent.
>
> If having separate configure/make stuff for each of these things
> sounds a bit heavyweight, we could just have a target-stubs.c which
> #includes cpu.h and has a lot of
> #ifndef TARGET_QUERY_CPUDEFS
> [stub version]
> #endif
> #ifndef TARGET_GET_MEMORY_MAPPING
> [stub version]
> #endif
This is pretty hideous.
FWIW, weak symbols are supported on OS X as of 10.2.
Regards,
Anthony Liguori
>
> etc.
>
> -- PMM
More information about the libvir-list
mailing list