Libguestfs - Jan 2022 - [PATCH 0/3] resolve conflict between manual and libvirt-assigned PCI addresses

On Thu, Dec 23, 2021 at 11:36:58AM +0100, Laszlo Ersek
wrote:
> Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2034160
> 
> The first patch extends our current <qemu:commandline> hack, moving
the
> virtio-net-pci device to slot 0x1E, where it is very unlikely to
> conflict with any libvirt-assigned PCI address.
Remind me why we still need to use <qemu:commandline> ? A need
for this obviously reflects a failure of libvirt to address the
libguestfs requirements. Can we fix the root cause here with proper
XML support for whatever feature is missing. 

Regards,
Daniel
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On Tue, Jan 04, 2022 at 10:33:14AM +0000, Daniel P. Berrang?
wrote:
> On Thu, Dec 23, 2021 at 11:36:58AM +0100, Laszlo Ersek wrote:
> > Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2034160
> > 
> > The first patch extends our current <qemu:commandline> hack,
moving the
> > virtio-net-pci device to slot 0x1E, where it is very unlikely to
> > conflict with any libvirt-assigned PCI address.
> 
> Remind me why we still need to use <qemu:commandline> ? A need
> for this obviously reflects a failure of libvirt to address the
> libguestfs requirements. Can we fix the root cause here with proper
> XML support for whatever feature is missing. 
Laszlo actually fixed this properly in the case we care about (modern
libvirt), if you look at the 3rd patch which went upstream:

https://github.com/libguestfs/libguestfs/commit/5858c2cf6c24b3776e3867eafd9d86a1f4912d9c

Ignoring the old libvirt case, the only reason we still need
<qemu:commandline> is to allow us to set TMPDIR accurately.
(Otherwise if you recall we can get a TMPDIR from an unrelated run of
libguestfs that happens to share the same session libvirtd).

The final code should make this clear:

https://github.com/libguestfs/libguestfs/blob/d1e7e1a323619d8f1e913a7833d07009f02a2d33/lib/launch-libvirt.c#L1838-L1899

Rich.

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