Re: [PATCH 12/15] hyperv: move VMBus connection ids to uapi

From: Paolo Bonzini
Date: Wed Dec 21 2016 - 10:40:02 EST




On 21/12/2016 15:26, Christoph Hellwig wrote:
> On Wed, Dec 21, 2016 at 03:59:20PM +0300, Roman Kagan wrote:
>> That's fine by me.
>>
>> I guess the series should then start with a complete move
>> arch/x86/include/uapi/asm/hyperv.h ->
>> arch/x86/include/asm/hyperv_proto.h, and the remaining patches have to
>> change the latter instead of the former?
>
> That would be my preference, but we'll need to figure out why
> hyperv has ever been a UABI header, and if anyone is using it.

QEMU uses it, but we already bundle the header files and update them
periodically from the files that Linux installs. So any change in Linux
would not break the QEMU build; having the header in UAPI is convenient
but I guess our update scripts could do whatever Linux's
scripts/headers_install.sh does.

That said, there are precedents in using UAPI this way for PV
interfaces. See for example include/uapi/linux/virtio*.h and
arch/x86/include/uapi/asm/kvm_para.h.

Paolo