Re: [PATCH v2 6/8] libvhost-user: check memfd API

[Michael S. Tsirkin]

On Wed, Dec 02, 2020 at 02:27:53PM +0000, Stefan Hajnoczi wrote:
> On Wed, Nov 25, 2020 at 02:06:38PM +0400, marcandre.lureau@redhat.com wrote:
> > From: Marc-André Lureau <marcandre.lureau@redhat.com>
> > 
> > Do not compile potentially panicking code, instead check memfd API is
> > present during configure time.
> > 
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > ---
> >  subprojects/libvhost-user/libvhost-user.c |  6 ------
> >  subprojects/libvhost-user/meson.build     | 12 ++++++++++++
> >  2 files changed, 12 insertions(+), 6 deletions(-)
> 
> Runtime checks are useful in environments where the QEMU and kernel
> version are not matched. In other words, if QEMU can be built against
> new kernel headers and launched on an old kernel then it needs to handle
> ENOSYS. But in some cases this situation is unlikely and we can stick to
> static feature checks. I'm not sure if it matters here, so...
> 
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

It's a good point, and given this patch also made build fail on a bunch
of systems, I dropped it.

-- 
MST