[Pkg-xen-devel] Bug#795330: Bug#795330: Suggests noapic but doesn't support it

[Ian Campbell]

Control: tag -1 upstream 

Jan/Andy & David,

Is there anything we can improve here on either the Xen or kernel side do
you think?

On Thu, 2015-08-13 at 00:59 +0200, Guido Günther wrote:
> Package: xen-hypervisor-4.5-amd64
> Severity: normal
> 
> Hi,
> when running xen inside of kvm the hypervisor fails to set up the proper
> IRQ routing and suggests to use noapic.

FTR, it seems to say:

    panic("IO-APIC + timer doesn't work!  Boot with apic_verbosity=debug "
          "and send a report.  Then try booting with the 'noapic' option");

Did you also try the first thing it suggested? What was the result?

>  If you add this via
> 
>     GRUB_CMDLINE_XEN_DEFAULT
> 
> it will boot futher but then report that noapic isn't supported.

Is this the kernel saying that or Xen? Do you have full boot logs?

I think it is the kernel since I can't find such a message in Xen and 
http://xenbits.xen.org/docs/unstable/misc/xen-command-line.html says for
the noapic option: "This is not recommended with pvops type kernels."

> So please make Xen not claim to support noapic if it doesn't

I think ultimately this is down to different components being able to
support different things, e.g. Xen's advice might be fine with a FreeBSD
dom0 or some other version of Linux.

>  (the issue
> was finally resolved by removeing all virtion devices and doubling the

                                        ^virtio ?

> hypervisors RAM so the suggestion was misplaced anyways).

I can see how the virtio thing might make the KVM guest look different to
Xen, but the RAM thing seems orthogonal.

Thanks,
Ian.