Re: NetBSD dom0 PVH: hardware interrupts stalls

[Manuel Bouyer <bouyer@xxxxxxxxxxxxxxx>]

On Wed, Nov 18, 2020 at 10:43:27AM +0100, Jan Beulich wrote:
> On 18.11.2020 10:28, Manuel Bouyer wrote:
> > On Wed, Nov 18, 2020 at 10:16:17AM +0100, Jan Beulich wrote:
> >> On 17.11.2020 17:40, Manuel Bouyer wrote:
> >>> On Tue, Nov 17, 2020 at 04:58:07PM +0100, Roger Pau Monné wrote:
> >>>> [...]
> >>>>
> >>>> I have attached a patch below that will dump the vIO-APIC info as part
> >>>> of the 'i' debug key output, can you paste the whole output of the 'i'
> >>>> debug key when the system stalls?
> >>>
> >>> see attached file. Note that the kernel did unstall while 'i' output was
> >>> being printed, so it is mixed with some NetBSD kernel output.
> >>
> >> Could you try to run Xen's serial port without use of any IRQ
> >> (i.e. in "polling" mode), in an attempt to avoid this unstalling
> >> (which is likely to render the resulting output at least in part
> >> meaningless)?
> > 
> > It there a boot line option for that ?
> 
> Yes, com<N>= has a field for this:
> 
> ### com1
> ### com2
> > `= 
> > <baud>[/<base-baud>][,[DPS][,[<io-base>|pci|amt][,[<irq>|msi][,[<port-bdf>][,[<bridge-bdf>]]]]]]`
> 
> with
> 
> * `<irq>` is the IRQ number to use, or `0` to use the UART in poll
>   mode only, or `msi` to set up a Message Signaled Interrupt.

thanks.
This marginally changes the boot behavior (the kenrel hangs a little bit
earlier) but switching the console input to Xen is enough to get some
interrupt, and hitting 'i' causes again the boot to complete.

-- 
Manuel Bouyer <bouyer@xxxxxxxxxxxxxxx>
     NetBSD: 26 ans d'experience feront toujours la difference
--