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

[Thomas Huth]

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...

 Thomas