2 files changed, 14 insertions, 25 deletions

diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index 13f33ea8ccaa..3b2e55e8ad2b 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -172,6 +172,9 @@ void smp_reschedule_interrupt(struct pt_regs *regs)
 {
         ack_APIC_irq();
         inc_irq_stat(irq_resched_count);
+        /*
+         * KVM uses this interrupt to force a cpu out of guest mode
+         */
 }
 
 void smp_call_function_interrupt(struct pt_regs *regs)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 75927700a26d..3c4c327490af 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3230,6 +3230,9 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 
         local_irq_disable();
 
+        clear_bit(KVM_REQ_KICK, &vcpu->requests);
+        smp_mb__after_clear_bit();
+
         if (vcpu->requests || need_resched() || signal_pending(current)) {
                 local_irq_enable();
                 preempt_enable();
@@ -3237,13 +3240,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                 goto out;
         }
 
-        vcpu->guest_mode = 1;
-        /*
-         * Make sure that guest_mode assignment won't happen after
-         * testing the pending IRQ vector bitmap.
-         */
-        smp_wmb();
-
         if (vcpu->arch.exception.pending)
                 __queue_exception(vcpu);
         else
@@ -3288,7 +3284,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         set_debugreg(vcpu->arch.host_dr6, 6);
         set_debugreg(vcpu->arch.host_dr7, 7);
 
-        vcpu->guest_mode = 0;
+        set_bit(KVM_REQ_KICK, &vcpu->requests);
         local_irq_enable();
 
         ++vcpu->stat.exits;
@@ -4571,30 +4567,20 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
                || vcpu->arch.nmi_pending;
 }
 
-static void vcpu_kick_intr(void *info)
-{
-#ifdef DEBUG
-        struct kvm_vcpu *vcpu = (struct kvm_vcpu *)info;
-        printk(KERN_DEBUG "vcpu_kick_intr %p \n", vcpu);
-#endif
-}
-
 void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
 {
-        int ipi_pcpu = vcpu->cpu;
-        int cpu;
+        int me;
+        int cpu = vcpu->cpu;
 
         if (waitqueue_active(&vcpu->wq)) {
                 wake_up_interruptible(&vcpu->wq);
                 ++vcpu->stat.halt_wakeup;
         }
-        /*
-         * We may be called synchronously with irqs disabled in guest mode,
-         * So need not to call smp_call_function_single() in that case.
-         */
-        cpu = get_cpu();
-        if (vcpu->guest_mode && vcpu->cpu != cpu)
-                smp_call_function_single(ipi_pcpu, vcpu_kick_intr, vcpu, 0);
+
+        me = get_cpu();
+        if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu))
+                if (!test_and_set_bit(KVM_REQ_KICK, &vcpu->requests))
+                        smp_send_reschedule(cpu);
         put_cpu();
 }