Re: [Qemu-devel] virtio-rng and fd passing

[Amit Shah]

On (Fri) 01 Mar 2013 [10:51:33], Paolo Bonzini wrote:
> Il 01/03/2013 01:36, Eric Blake ha scritto:
> > For fd passing to work, we have to use qemu_open() instead of raw
> > open().  Is there any way to enforce that all files being opened by qemu
> > go through the appropriate qemu_open() wrapper?
> > 
> > Meanwhile, we have a quandary on the libvirt side of things: qemu 1.4
> > supports fd passing in general, but does not support it for rng.  I
> > guess the same is true for -blockdev - we don't (yet) have a way to do
> > fd passing for backing files.  Do we need some sort of QMP command that
> > will let libvirt query for a particular device whether that device is
> > known to support fd passing, so that libvirt can use fd passing for all
> > supported devices, while falling back to older direct open()s, and to
> > know which instance of qemu can safely have open() blocked at the
> > SELinux or syscall blacklist level?
> 
> Let's change open to qemu_open for 1.4.1, and declare rng only supported
> in 1.4.1...

There are a few bugs that prevent the rng-random backend from working
properly.  I suspect we should move to using giochannel for the fd.


https://bugzilla.redhat.com/show_bug.cgi?id=917884
(issuing 'cat /dev/random' in host hits an assert and kills guest)

https://bugzilla.redhat.com/show_bug.cgi?id=917886
(default /dev/random backend doesn't send data to guest)

https://bugzilla.redhat.com/show_bug.cgi?id=915381
(performance of backends sucks)

                Amit