Re: Problem running 8.1R on KVM with AMD hosts
Luke Marsden
> > 1. Please, build your kernel with debug symbols.
> > 2. Show kgdb output
I could not convince the kernel to dump (it was looping forever but not
panicing), but I have managed to compiled a kernel with debugging
symbols and DDB which immediately drops into the debugger when the
problem occurs, see screenshot at:
http://lukemarsden.net/kvm-panic.png
Progress, I sense.
I tried typing 'panic' on the understanding that this should force a
panic and cause it would dump core to the configured swap device (I have
set dump* in /etc/rc.conf) so that I could get you the kgdb output, but
it just looped back into the debugger. This issue seems to occur very
early in the boot process.
I would like to invite anyone with the skills and the inclination to
have a poke around with this directly over VNC to email me off-list and
I will turn on the VM and send you the VNC credentials. My email address
is: luke [at] hybrid-logic.co.uk
Or you can catch me on Skype at luke.marsden. I'm in GMT+1.
I look forward to hearing from you ;-)
--
Best Regards,
Luke Marsden
Hybrid Logic Ltd.
Web: http://www.hybrid-cluster.com/
Hybrid Web Cluster - cloud web hosting based on FreeBSD and ZFS
Mobile: +447791750420
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Jung-uk Kim
> Hi FreeBSD-stable,
>
> > > 1. Please, build your kernel with debug symbols.
> > > 2. Show kgdb output
>
> I could not convince the kernel to dump (it was looping forever but
> not panicing), but I have managed to compiled a kernel with
> debugging symbols and DDB which immediately drops into the debugger
> when the problem occurs, see screenshot at:
>
> http://lukemarsden.net/kvm-panic.png
It seems MCA capability is advertised by the CPUID translator but
writing to the MSRs causes GPF. In other words, it seems like a CPU
emulator bug. A simple workaround is 'set hw.mca.enabled=0' from the
loader prompt. If it works, add hw.mca.enabled="0"
in /boot/loader.conf to make it permanent. MCA does not make any
sense in emulation any way.
Jung-uk Kim
Jeremy Chadwick
> Hi FreeBSD-stable,
>
> > > 1. Please, build your kernel with debug symbols.
> > > 2. Show kgdb output
>
> I could not convince the kernel to dump (it was looping forever but not
> panicing), but I have managed to compiled a kernel with debugging
> symbols and DDB which immediately drops into the debugger when the
> problem occurs, see screenshot at:
>
> http://lukemarsden.net/kvm-panic.png
>
>
> I tried typing 'panic' on the understanding that this should force a
> panic and cause it would dump core to the configured swap device (I have
> set dump* in /etc/rc.conf) so that I could get you the kgdb output, but
> it just looped back into the debugger.
Try "call doadump" instead.
--
| Jeremy Chadwick j...@parodius.com |
| Parodius Networking http://www.parodius.com/ |
| UNIX Systems Administrator Mountain View, CA, USA |
| Making life hard for others since 1977. PGP: 4BD6C0CB |
Luke Marsden
> It seems MCA capability is advertised by the CPUID translator but
> writing to the MSRs causes GPF. In other words, it seems like a CPU
> emulator bug. A simple workaround is 'set hw.mca.enabled=0' from the
> loader prompt. If it works, add hw.mca.enabled="0"
> in /boot/loader.conf to make it permanent. MCA does not make any
> sense in emulation any way.
Awesome, this allows us to boot 8.1R on Linux KVM with AMD hardware!
Thank you very much. This has just doubled our number of availability
zones.
--
Best Regards,
Luke Marsden
Hybrid Logic Ltd.
Web: http://www.hybrid-cluster.com/
Hybrid Web Cluster - cloud web hosting based on FreeBSD and ZFS
Mobile: +447791750420
_______________________________________________
Chris Webb
> On Thu, 2010-09-30 at 18:55 -0400, Jung-uk Kim wrote:
> > It seems MCA capability is advertised by the CPUID translator but
> > writing to the MSRs causes GPF. In other words, it seems like a CPU
> > emulator bug. A simple workaround is 'set hw.mca.enabled=0' from the
> > loader prompt. If it works, add hw.mca.enabled="0"
> > in /boot/loader.conf to make it permanent. MCA does not make any
> > sense in emulation any way.
Many thanks for tracking this one down for us!
> Awesome, this allows us to boot 8.1R on Linux KVM with AMD hardware!
I'll patch the system on lon-b not to advertise mca this morning Luke. It'll
be interesting to try again once I've done this to check if it fixes normal
booting without the extra hw.mca_enabled="0" flag.
Best wishes,
Chris.