tree 749cef5dcdc31bf0221f793ab7260559cfb54226
parent 0552f73b9a81d39d50b71a5c06cf36efff80b6fd
author Kevin Pedretti <kevin.pedretti@gmail.com> 1192949693 +0200
committer Avi Kivity <avi@qumranet.com> 1193047409 +0200

KVM: Fix local apic timer divide by zero

kvm_lapic_reset() was initializing apic->timer.divide_count to 0,
which could potentially lead to a divide by zero error in
apic_get_tmcct().  Any guest that reads the APIC's CCR (current count)
register before setting DCR (divide configuration) would trigger a divide
by zero exception in the host kernel, leading to a host-OS crash.

This patch results in apic->timer.divide_count being initialized to
2 at reset, eliminating the bug (DCR=0 at reset, meaning divide by 2).

Signed-off-by: Kevin Pedretti <kevin.pedretti@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>