Re: [Qemu-devel] [PATCH RFC] scripts/update-linux-headers.sh: pull virtio hdrs

[Peter Maydell]

On 11 February 2015 at 02:50, Chen, Tiejun <address@hidden> wrote:
> On 2015/2/11 10:03, Peter Maydell wrote:
>> The linux-headers/ directory contains header files which can only
>> validly be included if the host we're compiling on is Linux. Some
>> of them will cause compile failures on OSX or Windows if they
>> are in the include path. The idea of this patch is that the
>> standard-headers/ directory has "sanitized" header files which
>> have had the linux-specific types and includes stripped out.
>> So if we take the route this patch proposes we do need two
>> directories.
>>
>
> This confounds me since for instance, one of goals based on this patch is,
> it exposes those Virtio devices ID definition to hw/virtio, instead of my
> original patch, right? So without this sort of standard-hearders, how can we
> compile virtio? Or you mean we still keep those original stuff in
> include/hw/virtio*, but somehow update them once we execute that script
> manually.

I'm confused about why you're confused. We have two basic
approaches we can take:

(1) What we do at the moment. There are headers defining the virtio
interface in include/hw/virtio, and these are basically manually
created and updated as necessary.

(2) What this patch is proposing. The headers defining virtio are
automatically copied into standard-headers/ and fixed up to make
them work with QEMU on all the hosts we support. This happens when
this script is run by a developer to update QEMU's headers based
on some new upstream kernel.

Personally I think that option 1 is more reliable and overall
less effort, since automatiing the fixups is hard and virtio
doesn't change very much.

-- PMM