On Thu, May 21, 2020 at 09:23:50PM +0100, Al Viro wrote:
> On Thu, May 21, 2020 at 08:42:34PM +0100, Mark Cave-Ayland wrote:
>
> > > Can you tell me a bit more about the host in terms of CPU and disk to help figure out
> > > what's going on?
>
> phenom II X6 1100T (6-way 3.3GHz), 8Gb RAM (4Gb given to guest), WDC WD10EACS-00D
> disk (hdparm -tT gives
> Timing cached reads: 6988 MB in 2.00 seconds = 3494.96 MB/sec
> Timing buffered disk reads: 280 MB in 3.02 seconds = 92.75 MB/sec
> )
>
> > One other thought I had is that somehow the IVEC IRQs are managing to be overwritten
> > on a faster host before being read by the guest. Does the following patch display the
> > FATAL message at the point where things hang?
>
> > diff --git a/hw/pci-host/sabre.c b/hw/pci-host/sabre.c
> > index fae20ee97c..618ebd1300 100644
> > --- a/hw/pci-host/sabre.c
> > +++ b/hw/pci-host/sabre.c
> > @@ -63,6 +63,9 @@
> > static inline void sabre_set_request(SabreState *s, unsigned int irq_num)
> > {
> > trace_sabre_set_request(irq_num);
> > + if (s->irq_request != 0 && s->irq_request != NO_IRQ_REQUEST) {
> > + fprintf(stderr, "FATAL: still waiting for IRQ %x, now %x\n", s->irq_request,
> > irq_num);
> > + }
> > s->irq_request = irq_num;
> > qemu_set_irq(s->ivec_irqs[irq_num], 1);
> > }
>
> I have to go AFK right now, will test when I get back (should be about an
> hour or two)
Hang, nothing on stderr until killed, at which point it gave the expected
qemu-system-sparc64: terminating on signal 15 from pid 15917 (-bash)
IOW, stderr got flushed after hang - that fprintf simply has not triggered.
