Re: [PATCH] tests/functional: Convert the kvm_xen_guest avocado test

[Thomas Huth]

On 18/12/2024 17.19, Thomas Huth wrote:
> On 18/12/2024 15.11, David Woodhouse wrote:
> > On Wed, 2024-12-18 at 14:38 +0100, Thomas Huth wrote:
> ...
> > > But FWIW, there seems to be another issue with this test. While running it
> > > multiple times, I sometimes see test_kvm_xen_guest_novector_noapic hanging.
> > > According to the console output, the guest waits in vain for a device:
> > >
> > > 2024-12-18 14:32:58,606: Initializing XFRM netlink socket
> > > 2024-12-18 14:32:58,607: NET: Registered PF_INET6 protocol family
> > > 2024-12-18 14:32:58,609: Segment Routing with IPv6
> > > 2024-12-18 14:32:58,609: In-situ OAM (IOAM) with IPv6
> > > 2024-12-18 14:32:58,610: NET: Registered PF_PACKET protocol family
> > > 2024-12-18 14:32:58,610: 8021q: 802.1Q VLAN Support v1.8
> > > 2024-12-18 14:32:58,611: 9pnet: Installing 9P2000 support
> > > 2024-12-18 14:32:58,613: NET: Registered PF_VSOCK protocol family
> > > 2024-12-18 14:32:58,614: IPI shorthand broadcast: enabled
> > > 2024-12-18 14:32:58,619: sched_clock: Marking stable (551147059, 
> > > -6778955)->(590359530, -45991426)
> > > 2024-12-18 14:32:59,507: tsc: Refined TSC clocksource calibration: 
> > > 2495.952 MHz
> > > 2024-12-18 14:32:59,508: clocksource: tsc: mask: 0xffffffffffffffff 
> > > max_cycles: 0x23fa49fc138, max_idle_ns: 440795295059 ns
> > > 2024-12-18 14:32:59,509: clocksource: Switched to clocksource tsc
> > > 2024-12-18 14:33:28,667: xenbus_probe_frontend: Waiting for devices to 
> > > initialise: 25s...20s...15s...10s...5s...0s...
> > >
> > > Have you seen this problem before?
> >
> > That seems like event channel interrupts aren't being routed to the
> > legacy i8259 PIC. I've certainly seen that kind of thing before,
> > especially when asserted level-triggered interrupts weren't correctly
> > being asserted. But I don't expect that of QEMU. I'll see if I can
> > reproduce; thanks.
> >
> > How often does it happen?
>
> With the new functional test, it happens maybe 2 times out of 100 test runs.
>
> I wasn't able to reproduce it with the avocado version yet, but that also 
> runs 10x slower, so it takes a longer time to get to that many runs...

Ok, FWIW, I've now also seen the problem with the old avocado version of the 
test, so it's nothing that has been introduced by my patch. I just had to 
downgrade to Avocado v88 again since the current version v103 does not seem 
to correctly output the console anymore :-/ (which is another good indicator 
that we really need to get the stuff moved over to the functional framework 
now).

 Thomas