[Users] [Bug 881579] kernel-3.6.7-4 causes panic on FreeBSD KVM guest with >1 CPU

[Karli Sjöberg]

ons 2012-12-19 klockan 01:28 +0000 skrev bugzilla at redhat.com:


Product: Fedora
https://bugzilla.redhat.com/show_bug.cgi?id=881579

--- Comment #3 from Marcelo Tosatti <mtosatti at redhat.com<mailto:mtosatti at redhat.com>> ---
Its very likely the cause for this are instruction emulation upstream
(emulation of invalid guest state by default).

These are being fixed upstream. Once that is completed, it will be necessary to
backport
to FC17.

In the meantime, loading kvm-intel.ko with emulate_invalid_guest_state=0 should
work around the problem (tested locally on kvm.git as of dec/2012).



For future reference, I want to add what measures have been taken:

From oVirt Webadmin, the Host was set into Maintenance.

Then this file:
/etc/sysconfig/modules/kvm.modules:
#!/bin/sh

grep vmx /proc/cpuinfo >/dev/null 2>&1 && vmx=1
grep svm /proc/cpuinfo >/dev/null 2>&1 && svm=1

if [ "$vmx" ] || [ "$svm" ]; then
  [ "$vmx" ] && modprobe -b >/dev/null 2>&1
  [ "$svm" ] && modprobe -b kvm-amd >/dev/null 2>&1

  # no reason why vhost should not work with TCG, but currently it does not
  modprobe -b vhost-net >/dev/null 2>&1
else
  exit 0
fi

Was modfied to look like:
#!/bin/sh

grep vmx /proc/cpuinfo >/dev/null 2>&1 && vmx=1
grep svm /proc/cpuinfo >/dev/null 2>&1 && svm=1

if [ "$vmx" ] || [ "$svm" ]; then
  [ "$vmx" ] && modprobe -b kvm-intel emulate_invalid_guest_state=0 >/dev/null 2>&1
  [ "$svm" ] && modprobe -b kvm-amd >/dev/null 2>&1

  # no reason why vhost should not work with TCG, but currently it does not
  modprobe -b vhost-net >/dev/null 2>&1
else
  exit 0
fi

And after two reboots(didn´t get set after the first reboot, strangly enough) the setting have been confirmed persistant with:
# more /sys/module/kvm_intel/parameters/emulate_invalid_guest_state
N

The Host was again activated and the guest panics are gone.

Thanks for the hint!

/Karli

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