KVM: Emulate hlt in the kernel

By sleeping in the kernel when hlt is executed, we simplify the in-kernel
guest interrupt path considerably.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/kvm/irq.c b/drivers/kvm/irq.c
index 5265f8267b3b..e09cd65925d6 100644
--- a/drivers/kvm/irq.c
+++ b/drivers/kvm/irq.c
@@ -70,6 +70,10 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
 {
         int ipi_pcpu = vcpu->cpu;
 
+        if (waitqueue_active(&vcpu->wq)) {
+                wake_up_interruptible(&vcpu->wq);
+                ++vcpu->stat.halt_wakeup;
+        }
         if (vcpu->guest_mode)
                 smp_call_function_single(ipi_pcpu, vcpu_kick_intr, vcpu, 0, 0);
 }