Xen 8 & 9 DomU kernel panic with 2 or more virtual CPU

[John Prather]

This seems to affect most people trying to use FreeBSD on xen i386 paravirt.

I was trying it on Linode, and got 8.0-RELEASE to actually boot by
hacking MAXCPU to 1 in sys/i386/include/param.h but even then, when it
was under load (building world or lots of ports) it would occasionally
panic.

8-STABLE wouldn't even boot with MAXCPU hacked to 1 to avoid
VCPUOP_initialise panic, throwing panic on
HYPERVISOR_update_va_mapping instead.

I played around a bit with hacking the sys source, but I don't know
enough about XEN or even FreeBSD kernel behavior to figure out what's
going wrong here.



On Fri, May 14, 2010 at 4:31 AM, masterito <admin at masterito.spb.ru> wrote:
> Hello.
>
> I have the same problem, but other error.
>
> When I create machine with 1 CPU (vcpus=1) - all work fine, but when
> I  create machine with 4 CPU (vcpus=4) I see kernel panic on console:
>
> APIC: Using the MPTable enumerator.
> SMP: Added CPU 0 (BSP)
> SMP: Added CPU 1 (AP)
> SMP: Added CPU 2 (AP)
> SMP: Added CPU 3 (AP)
> gdtpfn=3df8cb pdptpfn=f63f4
> panic: HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu,
> &ctxt): /usr/src/sys/i386/xen/mp_machdep.c:929
> cpuid = 0
> KDB: enter: panic
> [thread pid 0 tid 0 ]
> Stopped at      kdb_enter+0x3a: movl    $0,kdb_why
> db>
>
> ---