Re: [PATCH v2 09/27] hw/xen: Add evtchn operations to allow redirection to internal emulation

[Anthony PERARD]

On Tue, Mar 07, 2023 at 05:17:32PM +0000, David Woodhouse wrote:
> From: David Woodhouse <dwmw@amazon.co.uk>
> 
> The existing implementation calling into the real libxenevtchn moves to
> a new file hw/xen/xen-operations.c, and is called via a function table
> which in a subsequent commit will also be able to invoke the emulated
> event channel support.
> 
> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
> Reviewed-by: Paul Durrant <paul@xen.org>

Hi David, Paul,

This patch prevents existing use case from booting, that is even with the
state change notification fix. It seems that trying to create a PV guest
with libvirt fails, with "xen be core: can't connect to xenstored" in
QEMU's log but it doesn't says if that's the reason qemu failed to
start. But it's probably not related to libvirt.

Our bisector pointed out this patch, see details and logs:
    
https://lore.kernel.org/xen-devel/E1pdvdx-0006lh-Oe@osstest.test-lab.xenproject.org/
    
https://lore.kernel.org/xen-devel/E1pcg3G-0000NS-9x@osstest.test-lab.xenproject.org/
    
https://lore.kernel.org/xen-devel/E1pf9hf-0005EB-1r@osstest.test-lab.xenproject.org/

I did run a test with patch "Fix DM state change notification in
dm_restrict mode", but I think only the *dmrestict* tests have been
fixed.
    http://logs.test-lab.xenproject.org/osstest/logs/179868/

Some failures of running PV guests without libvirt, from that flight:
    
http://logs.test-lab.xenproject.org/osstest/logs/179868/test-amd64-amd64-xl-qcow2/info.html
    
http://logs.test-lab.xenproject.org/osstest/logs/179868/test-amd64-i386-xl-vhd/info.html

Any idea of what's wrong?

Thanks,

-- 
Anthony PERARD