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| author | Marcelo Tosatti <mtosatti@redhat.com> | 2008-06-06 16:37:36 -0300 |
|---|---|---|
| committer | Avi Kivity <avi@qumranet.com> | 2008-06-24 12:16:59 +0300 |
| commit | 06e05645661211b9eaadaf6344c335d2e80f0ba2 (patch) | |
| tree | 8846d2a5052aec44141e811c0a76fdb39c2e77ca /arch/x86/kvm/i8254.c | |
| parent | d4acf7e7abe45457e751525a2a4d5b693dfdd597 (diff) | |
| download | linux-06e05645661211b9eaadaf6344c335d2e80f0ba2.tar.bz2 | |
KVM: close timer injection race window in __vcpu_run
If a timer fires after kvm_inject_pending_timer_irqs() but before
local_irq_disable() the code will enter guest mode and only inject such
timer interrupt the next time an unrelated event causes an exit.
It would be simpler if the timer->pending irq conversion could be done
with IRQ's disabled, so that the above problem cannot happen.
For now introduce a new vcpu requests bit to cancel guest entry.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'arch/x86/kvm/i8254.c')
| -rw-r--r-- | arch/x86/kvm/i8254.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index f2f5d260874e..3829aa7b663f 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -200,9 +200,12 @@ int __pit_timer_fn(struct kvm_kpit_state *ps) atomic_inc(&pt->pending); smp_mb__after_atomic_inc(); - if (vcpu0 && waitqueue_active(&vcpu0->wq)) { - vcpu0->arch.mp_state = KVM_MP_STATE_RUNNABLE; - wake_up_interruptible(&vcpu0->wq); + if (vcpu0) { + set_bit(KVM_REQ_PENDING_TIMER, &vcpu0->requests); + if (waitqueue_active(&vcpu0->wq)) { + vcpu0->arch.mp_state = KVM_MP_STATE_RUNNABLE; + wake_up_interruptible(&vcpu0->wq); + } } pt->timer.expires = ktime_add_ns(pt->timer.expires, pt->period); |