Re: [Qemu-devel] Xen patches - status summary

[Gerd Hoffmann <kraxel@redhat.com>]

Ian Jackson wrote:
> I don't know about you but I'm starting to lose track of all the
> patches we're submitting from the Xen tree.  So here's a summary of
> recent activity:
> 
> Patches from Stefano Stabellini awaiting commit to qemu:
> 
>  [1/3] vnc dynamic resolution	} minor discussion, all issues resolved
>  [2/3] WMVi extension support	}  so should IMO be applied (updated version
>  [3/3] vga shared buffer	}  in case of vga shared buffer patch)
>  sdl shared buffer support	  no discussion, should be applied IMO
>  opengl rendering in the sdl ...  no discussion, should be applied IMO

I think they still sitting in anthonys inbox waiting for review ...

> Looking at my git logs here there are quite a few more which will be
> forthcoming but perhaps it would be good to digest these first ?

In case you don't know what to do with your time meanwhile:
/me waits for qemu-xen catching up with upstream, so I can update and
respin the patch series ;)

> [1] Re: Use fd signal trick to break us out of select
>     Re: Introduce #define QEMU_ASYNC_EVENTLOOP
> 
> Anthony Ligouri had a different patch based on a helper thread to
> provide an emulation of signalfd rather than use of a signal handler.
> However (as confirmed by Jamie Lokier) some versions of glibc have
> a bug in the handling of the glibc internal aio helper thread(s)
> which can make efforts to block signals ineffective.  This means
> that Anthony's patch will not work properly on those libcs and as
> I wrote already this means that my patch should be applied.

I also tend to dislike os-specific stuff due to the portability issues
it brings.  Sometimes there are good reasons to use it nevertheless.

> The QEMU_ASYNC_EVENTLOOP change is a tidying up of the NBD feature to
> make qemu-nbd share more commonality with qemu-img.  As discussed
> there are perhaps even more cleanups that could be done to improve
> this but as I say this change is a good start and should be applied.

Cleanups is, well, not the correct word IMHO.  The complete block device
handling needs a major redesign.  That this ifdef is needed in the first
place is a blatant layering violation.  Also we should be able to
support async I/O in some form (be it libaio, threads or whatever)
without hacking support for it into each and every file format handler.

> [2] Re: usb-linux.c: #define __user to work around broken Linux headers
> 
> Thiemo Seufer complained that `distros should fix their broken
> headers instead', which as I said is I think a ridiculous argument.
> The headers have indeed been fixed in most upstreams but we would like
> to be portable to older unfixed systems.  No-one else has commented.

It's fixed for quite a while.  Any *supported* distros where this is
still an issue?  I saw you mention Fedora Core 6.  There are no
(security) updates any more for this one, so nobody should seriously use
it these days ...

As those workarounds tend to hand around even when the reason to
introduce them is long gone I'd agree to better not apply this one.

> [3] Re: IDE error checking

Yep, this certainly needs to be fixed.
/me votes for applying them, although I don't know IDE good enougth to
comment on the patches themself.

cheers,
  Gerd