Re: [PATCH] tests/qtest/migration: Restore include for postcopy

[Fabiano Rosas]

Daniel P. Berrangé <berrange@redhat.com> writes:

> On Tue, Dec 17, 2024 at 04:47:39PM -0500, Peter Xu wrote:
>> On Tue, Dec 17, 2024 at 06:22:01PM -0300, Fabiano Rosas wrote:
>> > Commit 124a3c58b8 ("tests/qtest/migration: Move ufd_version_check to
>> > utils") moved the ufd_version_check() function to another file but
>> > failed to bring along the <sys/syscall> include, which is necessary to
>> > pull in <asm/unistd.h> for __NR_userfaultd.
>> > 
>> > Restore the missing include.
>> 
>> Ohhhhhhh.. so postcopy tests will always be skipped as of now?  Maybe worth
>> explicit mention that in the commit message if so, only when you merge.
>> 
>> > 
>> > While here, remove the ifdef __linux__ that's redundant and fix a
>> > couple of typos.
>> > 
>> > Fixes: 124a3c58b8 ("tests/qtest/migration: Move ufd_version_check to 
>> > utils")
>> > Signed-off-by: Fabiano Rosas <farosas@suse.de>
>> 
>> Reviewed-by: Peter Xu <peterx@redhat.com>
>> 
>> Maybe we don't need to be as careful on old kernels anymore especially in
>> tests, because userfaultfd syscall existed for ~10 years. So if we want we
>> can start requiring __NR_userfaultfd present for __linux__, then no way to
>> miss such spot next time.
>
> Yes, I think that check is obsolete, based on our supported platforms
> list. It would suffice to just check __linux__.

This breaks the cross builds. It seems the __NR_userfaultfd was actually
stopping several archs from reaching ufd_version_check(). Since
<sys/ioctl.h> is under HOST_X86_64, these new instances now fail to find
the 'ioctl' symbol:

https://gitlab.com/farosas/qemu/-/pipelines/1594332399

Of course I could just include <sys/ioctl.h> unconditionally, but the
fact that new code is not being built means the assumption that we can
imply __NR_userfaultfd from __linux__ alone is not correct.