tree a078acb4c626432ac8cf887b911d912f4a316d06
parent 1b7fcd3263e5f12dba43d27b64e1578bec070c28
author Avi Kivity <avi@qumranet.com> 1210674218 +0300
committer Avi Kivity <avi@qumranet.com> 1216546903 +0300

KVM: Handle virtualization instruction #UD faults during reboot

KVM turns off hardware virtualization extensions during reboot, in order
to disassociate the memory used by the virtualization extensions from the
processor, and in order to have the system in a consistent state.
Unfortunately virtual machines may still be running while this goes on,
and once virtualization extensions are turned off, any virtulization
instruction will #UD on execution.

Fix by adding an exception handler to virtualization instructions; if we get
an exception during reboot, we simply spin waiting for the reset to complete.
If it's a true exception, BUG() so we can have our stack trace.

Signed-off-by: Avi Kivity <avi@qumranet.com>