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

["Chen, Tiejun" <tiejun.chen@intel.com>]

On 2015/2/11 10:03, Peter Maydell wrote:
> On 11 February 2015 at 01:36, Chen, Tiejun <tiejun.chen@intel.com> wrote:
>> On 2015/2/10 3:56, Michael S. Tsirkin wrote:
>>>
>>> It doesn't make sense to copy values manually:
>>> the only issue with getting headers from linux
>>> seems to be dealing with linux/types, we
>>> can easily fix that automatically while importing.
>>>
>>> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
>>> ---
>>>
>>> FYI this is what I propose instead of the recently
>>> suggested
>>>       virtio: uniform virtio device IDs
>>> we can then rework existing code to include these headers.
>>>
>>> Will automatically bring in goodies as they arrive in linux.
>>>
>>> This doesn't yet import virtio ccw header,
>>> that won't be hard to add later.
>>>
>>>    scripts/update-linux-headers.sh | 10 ++++++++++
>>>    1 file changed, 10 insertions(+)
>>>
>>> diff --git a/scripts/update-linux-headers.sh
>>> b/scripts/update-linux-headers.sh
>>> index c8e026d..0bd8437 100755
>>> --- a/scripts/update-linux-headers.sh
>>> +++ b/scripts/update-linux-headers.sh
>>> @@ -76,4 +76,14 @@ else
>>>        cp "$linux/COPYING" "$output/linux-headers"
>>>    fi
>>>
>>> +rm -rf "$output/standard-headers/linux"
>>> +mkdir -p "$output/standard-headers/linux"
>>
>>
>> Shouldn't we add something in configure file to execute this automatically?
>
> No. We want to run this script only when we're updating the
> header files, which only happens when we have a valid
> kernel source tree available and you're a developer doing
> it as a specific action. configure is run by everybody and
> should definitely not be doing header updates.
>
>> Or instead of creating 'standard-headers/, why can't we go that existing
>> linux-headers/?
>
> 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.

Thanks
Tiejun