Re: mips system emulation failure with virtio

[Richard Purdie]

On Tue, 2023-09-05 at 14:59 +0100, Alex Bennée wrote:
> Richard Purdie <richard.purdie@linuxfoundation.org> writes:
> 
> > With qemu 8.1.0 we see boot hangs fox x86-64 targets. 
> > 
> > These are fixed by 0d58c660689f6da1e3feff8a997014003d928b3b (softmmu:
> > Use async_run_on_cpu in tcg_commit) but if I add that commit, mips and
> > mips64 break, hanging at boot unable to find a rootfs. 
> 
> (Widen CC list)
> 
> > 
> > We use virtio for network and disk and both of those change in the
> > bootlog from messages like:
> > 
> > [    1.726118] virtio-pci 0000:00:13.0: enabling device (0000 -> 0003)
> > [    1.728864] virtio-pci 0000:00:14.0: enabling device (0000 -> 0003)
> > [    1.729948] virtio-pci 0000:00:15.0: enabling device (0000 -> 0003)
> > ...
> > [    2.162148] virtio_blk virtio2: 1/0/0 default/read/poll queues
> > [    2.168311] virtio_blk virtio2: [vda] 1184242 512-byte logical 
> > 
> > to:
> > 
> > [    1.777051] virtio-pci 0000:00:13.0: enabling device (0000 -> 0003)
> > [    1.779822] virtio-pci 0000:00:14.0: enabling device (0000 -> 0003)
> > [    1.780926] virtio-pci 0000:00:15.0: enabling device (0000 -> 0003)
> > ...
> > [    1.894852] virtio_rng: probe of virtio1 failed with error -28
> > ...
> > [    2.063553] virtio_blk virtio2: 1/0/0 default/read/poll queues
> > [    2.064260] virtio_blk: probe of virtio2 failed with error -28
> > [    2.069080] virtio_net: probe of virtio0 failed with error -28
> > 
> > 
> > i.e. the virtio drivers no longer work.
> 
> Interesting, as you say this seems to be VirtIO specific as the baseline
> tests (using IDE) work fine:
> 
>   ➜  ./tests/venv/bin/avocado run 
> ./tests/avocado/tuxrun_baselines.py:test_mips64
>   JOB ID     : 71f3e3b7080164b78ef1c8c1bb6bc880932d8c9b
>   JOB LOG    : 
> /home/alex/avocado/job-results/job-2023-09-05T15.01-71f3e3b/job.log
>    (1/2) ./tests/avocado/tuxrun_baselines.py:TuxRunBaselineTest.test_mips64: 
> PASS (12.19 s)
>    (2/2) 
> ./tests/avocado/tuxrun_baselines.py:TuxRunBaselineTest.test_mips64el: PASS 
> (11.78 s)
>   RESULTS    : PASS 2 | ERROR 0 | FAIL 0 | SKIP 0 | WARN 0 | INTERRUPT 0 | 
> CANCEL 0
>   JOB TIME   : 24.79 s
> 
> > I tested with current qemu master
> > (17780edd81d27fcfdb7a802efc870a99788bd2fc) and mips is still broken
> > there.
> > 
> > Is this issue known about?
> 
> Could you raise a bug at:
> 
>   https://gitlab.com/qemu-project/qemu/-/issues

Done, https://gitlab.com/qemu-project/qemu/-/issues/1866

> I'm curious why MIPS VirtIO is affected but nothing else is...

Me too, it seems there is a real code issue somewhere in this...

Cheers,

Richard