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| author | Kevin Pedretti <kevin.pedretti@gmail.com> | 2007-10-21 08:54:53 +0200 |
|---|---|---|
| committer | Avi Kivity <avi@qumranet.com> | 2007-10-22 12:03:29 +0200 |
| commit | b33ac88b4c23330043acad930517282eb486db1d (patch) | |
| tree | 749cef5dcdc31bf0221f793ab7260559cfb54226 /drivers/kvm | |
| parent | 0552f73b9a81d39d50b71a5c06cf36efff80b6fd (diff) | |
| download | linux-stable-b33ac88b4c23330043acad930517282eb486db1d.tar.gz linux-stable-b33ac88b4c23330043acad930517282eb486db1d.tar.bz2 linux-stable-b33ac88b4c23330043acad930517282eb486db1d.zip | |
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>
Diffstat (limited to 'drivers/kvm')
| -rw-r--r-- | drivers/kvm/lapic.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/kvm/lapic.c b/drivers/kvm/lapic.c index a190587cf6a5..443730e689e3 100644 --- a/drivers/kvm/lapic.c +++ b/drivers/kvm/lapic.c @@ -853,7 +853,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu) apic_set_reg(apic, APIC_ISR + 0x10 * i, 0); apic_set_reg(apic, APIC_TMR + 0x10 * i, 0); } - apic->timer.divide_count = 0; + update_divide_count(apic); atomic_set(&apic->timer.pending, 0); if (vcpu->vcpu_id == 0) vcpu->apic_base |= MSR_IA32_APICBASE_BSP; |