Problem running 8.1R on KVM with AMD hosts

Jung-uk Kim jkim at
Thu Sep 30 22:56:00 UTC 2010

On Thursday 30 September 2010 02:57 pm, Luke Marsden wrote:
> 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:

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

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