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>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b90744a..b08812d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2774,6 +2774,7 @@
}
}
+ clear_bit(KVM_REQ_PENDING_TIMER, &vcpu->requests);
kvm_inject_pending_timer_irqs(vcpu);
preempt_disable();