diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 100df6f..32023d1 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -173,6 +173,7 @@
 	struct mutex mutex;
 	int   cpu;
 	int   launched;
+	int interrupt_window_open;
 	unsigned long irq_summary; /* bit vector: 1 per word in irq_pending */
 #define NR_IRQ_WORDS KVM_IRQ_BITMAP_SIZE(unsigned long)
 	unsigned long irq_pending[NR_IRQ_WORDS];
@@ -247,6 +248,9 @@
 	u32 io_exits;
 	u32 mmio_exits;
 	u32 signal_exits;
+	u32 irq_window_exits;
+	u32 halt_exits;
+	u32 request_irq_exits;
 	u32 irq_exits;
 };
 
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index b54caf0..aca14139 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -58,6 +58,9 @@
 	{ "io_exits", &kvm_stat.io_exits },
 	{ "mmio_exits", &kvm_stat.mmio_exits },
 	{ "signal_exits", &kvm_stat.signal_exits },
+	{ "irq_window", &kvm_stat.irq_window_exits },
+	{ "halt_exits", &kvm_stat.halt_exits },
+	{ "request_irq", &kvm_stat.request_irq_exits },
 	{ "irq_exits", &kvm_stat.irq_exits },
 	{ 0, 0 }
 };
@@ -1693,12 +1696,12 @@
 		if (copy_from_user(&kvm_run, (void *)arg, sizeof kvm_run))
 			goto out;
 		r = kvm_dev_ioctl_run(kvm, &kvm_run);
-		if (r < 0)
+		if (r < 0 &&  r != -EINTR)
 			goto out;
-		r = -EFAULT;
-		if (copy_to_user((void *)arg, &kvm_run, sizeof kvm_run))
+		if (copy_to_user((void *)arg, &kvm_run, sizeof kvm_run)) {
+			r = -EFAULT;
 			goto out;
-		r = 0;
+		}
 		break;
 	}
 	case KVM_GET_REGS: {
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index fa04287..855207a 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -235,6 +235,8 @@
 
 	vcpu->rip = vcpu->svm->vmcb->save.rip = vcpu->svm->next_rip;
 	vcpu->svm->vmcb->control.int_state &= ~SVM_INTERRUPT_SHADOW_MASK;
+
+	vcpu->interrupt_window_open = 1;
 }
 
 static int has_svm(void)
@@ -1031,10 +1033,11 @@
 {
 	vcpu->svm->next_rip = vcpu->svm->vmcb->save.rip + 1;
 	skip_emulated_instruction(vcpu);
-	if (vcpu->irq_summary && (vcpu->svm->vmcb->save.rflags & X86_EFLAGS_IF))
+	if (vcpu->irq_summary)
 		return 1;
 
 	kvm_run->exit_reason = KVM_EXIT_HLT;
+	++kvm_stat.halt_exits;
 	return 0;
 }
 
@@ -1186,6 +1189,24 @@
 		return rdmsr_interception(vcpu, kvm_run);
 }
 
+static int interrupt_window_interception(struct kvm_vcpu *vcpu,
+				   struct kvm_run *kvm_run)
+{
+	/*
+	 * If the user space waits to inject interrupts, exit as soon as
+	 * possible
+	 */
+	if (kvm_run->request_interrupt_window &&
+	    !vcpu->irq_summary &&
+	    (vcpu->svm->vmcb->save.rflags & X86_EFLAGS_IF)) {
+		++kvm_stat.irq_window_exits;
+		kvm_run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
+		return 0;
+	}
+
+	return 1;
+}
+
 static int (*svm_exit_handlers[])(struct kvm_vcpu *vcpu,
 				      struct kvm_run *kvm_run) = {
 	[SVM_EXIT_READ_CR0]           		= emulate_on_interception,
@@ -1210,6 +1231,7 @@
 	[SVM_EXIT_NMI]				= nop_on_interception,
 	[SVM_EXIT_SMI]				= nop_on_interception,
 	[SVM_EXIT_INIT]				= nop_on_interception,
+	[SVM_EXIT_VINTR]			= interrupt_window_interception,
 	/* [SVM_EXIT_CR0_SEL_WRITE]		= emulate_on_interception, */
 	[SVM_EXIT_CPUID]			= cpuid_interception,
 	[SVM_EXIT_HLT]				= halt_interception,
@@ -1278,15 +1300,11 @@
 }
 
 
-static inline void kvm_try_inject_irq(struct kvm_vcpu *vcpu)
+static inline void kvm_do_inject_irq(struct kvm_vcpu *vcpu)
 {
 	struct vmcb_control_area *control;
 
-	if (!vcpu->irq_summary)
-		return;
-
 	control = &vcpu->svm->vmcb->control;
-
 	control->int_vector = pop_irq(vcpu);
 	control->int_ctl &= ~V_INTR_PRIO_MASK;
 	control->int_ctl |= V_IRQ_MASK |
@@ -1301,6 +1319,59 @@
 		control->int_ctl &= ~V_IRQ_MASK;
 		push_irq(vcpu, control->int_vector);
 	}
+
+	vcpu->interrupt_window_open =
+		!(control->int_state & SVM_INTERRUPT_SHADOW_MASK);
+}
+
+static void do_interrupt_requests(struct kvm_vcpu *vcpu,
+				       struct kvm_run *kvm_run)
+{
+	struct vmcb_control_area *control = &vcpu->svm->vmcb->control;
+
+	vcpu->interrupt_window_open =
+		(!(control->int_state & SVM_INTERRUPT_SHADOW_MASK) &&
+		 (vcpu->svm->vmcb->save.rflags & X86_EFLAGS_IF));
+
+	if (vcpu->interrupt_window_open && vcpu->irq_summary)
+		/*
+		 * If interrupts enabled, and not blocked by sti or mov ss. Good.
+		 */
+		kvm_do_inject_irq(vcpu);
+
+	/*
+	 * Interrupts blocked.  Wait for unblock.
+	 */
+	if (!vcpu->interrupt_window_open &&
+	    (vcpu->irq_summary || kvm_run->request_interrupt_window)) {
+		control->intercept |= 1ULL << INTERCEPT_VINTR;
+	} else
+		control->intercept &= ~(1ULL << INTERCEPT_VINTR);
+}
+
+static void post_kvm_run_save(struct kvm_vcpu *vcpu,
+			      struct kvm_run *kvm_run)
+{
+	kvm_run->ready_for_interrupt_injection = (vcpu->interrupt_window_open &&
+						  vcpu->irq_summary == 0);
+	kvm_run->if_flag = (vcpu->svm->vmcb->save.rflags & X86_EFLAGS_IF) != 0;
+	kvm_run->cr8 = vcpu->cr8;
+	kvm_run->apic_base = vcpu->apic_base;
+}
+
+/*
+ * Check if userspace requested an interrupt window, and that the
+ * interrupt window is open.
+ *
+ * No need to exit to userspace if we already have an interrupt queued.
+ */
+static int dm_request_for_irq_injection(struct kvm_vcpu *vcpu,
+					  struct kvm_run *kvm_run)
+{
+	return (!vcpu->irq_summary &&
+		kvm_run->request_interrupt_window &&
+		vcpu->interrupt_window_open &&
+		(vcpu->svm->vmcb->save.rflags & X86_EFLAGS_IF));
 }
 
 static void save_db_regs(unsigned long *db_regs)
@@ -1326,7 +1397,7 @@
 	u16 ldt_selector;
 
 again:
-	kvm_try_inject_irq(vcpu);
+	do_interrupt_requests(vcpu, kvm_run);
 
 	clgi();
 
@@ -1487,17 +1558,26 @@
 	if (vcpu->svm->vmcb->control.exit_code == SVM_EXIT_ERR) {
 		kvm_run->exit_type = KVM_EXIT_TYPE_FAIL_ENTRY;
 		kvm_run->exit_reason = vcpu->svm->vmcb->control.exit_code;
+		post_kvm_run_save(vcpu, kvm_run);
 		return 0;
 	}
 
 	if (handle_exit(vcpu, kvm_run)) {
 		if (signal_pending(current)) {
 			++kvm_stat.signal_exits;
+			post_kvm_run_save(vcpu, kvm_run);
+			return -EINTR;
+		}
+
+		if (dm_request_for_irq_injection(vcpu, kvm_run)) {
+			++kvm_stat.request_irq_exits;
+			post_kvm_run_save(vcpu, kvm_run);
 			return -EINTR;
 		}
 		kvm_resched(vcpu);
 		goto again;
 	}
+	post_kvm_run_save(vcpu, kvm_run);
 	return 0;
 }
 
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 2d204fd..c55635d 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -263,6 +263,7 @@
 	if (interruptibility & 3)
 		vmcs_write32(GUEST_INTERRUPTIBILITY_INFO,
 			     interruptibility & ~3);
+	vcpu->interrupt_window_open = 1;
 }
 
 static void vmx_inject_gp(struct kvm_vcpu *vcpu, unsigned error_code)
@@ -1214,21 +1215,34 @@
 			irq | INTR_TYPE_EXT_INTR | INTR_INFO_VALID_MASK);
 }
 
-static void kvm_try_inject_irq(struct kvm_vcpu *vcpu)
+
+static void do_interrupt_requests(struct kvm_vcpu *vcpu,
+				       struct kvm_run *kvm_run)
 {
-	if ((vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF)
-	    && (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0)
+	u32 cpu_based_vm_exec_control;
+
+	vcpu->interrupt_window_open =
+		((vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) &&
+		 (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0);
+
+	if (vcpu->interrupt_window_open &&
+	    vcpu->irq_summary &&
+	    !(vmcs_read32(VM_ENTRY_INTR_INFO_FIELD) & INTR_INFO_VALID_MASK))
 		/*
-		 * Interrupts enabled, and not blocked by sti or mov ss. Good.
+		 * If interrupts enabled, and not blocked by sti or mov ss. Good.
 		 */
 		kvm_do_inject_irq(vcpu);
-	else
+
+	cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
+	if (!vcpu->interrupt_window_open &&
+	    (vcpu->irq_summary || kvm_run->request_interrupt_window))
 		/*
 		 * Interrupts blocked.  Wait for unblock.
 		 */
-		vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
-			     vmcs_read32(CPU_BASED_VM_EXEC_CONTROL)
-			     | CPU_BASED_VIRTUAL_INTR_PENDING);
+		cpu_based_vm_exec_control |= CPU_BASED_VIRTUAL_INTR_PENDING;
+	else
+		cpu_based_vm_exec_control &= ~CPU_BASED_VIRTUAL_INTR_PENDING;
+	vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
 }
 
 static void kvm_guest_debug_pre(struct kvm_vcpu *vcpu)
@@ -1565,23 +1579,41 @@
 	return 1;
 }
 
+static void post_kvm_run_save(struct kvm_vcpu *vcpu,
+			      struct kvm_run *kvm_run)
+{
+	kvm_run->if_flag = (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) != 0;
+	kvm_run->cr8 = vcpu->cr8;
+	kvm_run->apic_base = vcpu->apic_base;
+	kvm_run->ready_for_interrupt_injection = (vcpu->interrupt_window_open &&
+						  vcpu->irq_summary == 0);
+}
+
 static int handle_interrupt_window(struct kvm_vcpu *vcpu,
 				   struct kvm_run *kvm_run)
 {
-	/* Turn off interrupt window reporting. */
-	vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
-		     vmcs_read32(CPU_BASED_VM_EXEC_CONTROL)
-		     & ~CPU_BASED_VIRTUAL_INTR_PENDING);
+	/*
+	 * If the user space waits to inject interrupts, exit as soon as
+	 * possible
+	 */
+	if (kvm_run->request_interrupt_window &&
+	    !vcpu->irq_summary &&
+	    (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF)) {
+		kvm_run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
+		++kvm_stat.irq_window_exits;
+		return 0;
+	}
 	return 1;
 }
 
 static int handle_halt(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
 	skip_emulated_instruction(vcpu);
-	if (vcpu->irq_summary && (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF))
+	if (vcpu->irq_summary)
 		return 1;
 
 	kvm_run->exit_reason = KVM_EXIT_HLT;
+	++kvm_stat.halt_exits;
 	return 0;
 }
 
@@ -1632,6 +1664,21 @@
 	return 0;
 }
 
+/*
+ * Check if userspace requested an interrupt window, and that the
+ * interrupt window is open.
+ *
+ * No need to exit to userspace if we already have an interrupt queued.
+ */
+static int dm_request_for_irq_injection(struct kvm_vcpu *vcpu,
+					  struct kvm_run *kvm_run)
+{
+	return (!vcpu->irq_summary &&
+		kvm_run->request_interrupt_window &&
+		vcpu->interrupt_window_open &&
+		(vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF));
+}
+
 static int vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
 	u8 fail;
@@ -1663,9 +1710,7 @@
 	vmcs_writel(HOST_GS_BASE, segment_base(gs_sel));
 #endif
 
-	if (vcpu->irq_summary &&
-	    !(vmcs_read32(VM_ENTRY_INTR_INFO_FIELD) & INTR_INFO_VALID_MASK))
-		kvm_try_inject_irq(vcpu);
+	do_interrupt_requests(vcpu, kvm_run);
 
 	if (vcpu->guest_debug.enabled)
 		kvm_guest_debug_pre(vcpu);
@@ -1802,6 +1847,7 @@
 
 	fx_save(vcpu->guest_fx_image);
 	fx_restore(vcpu->host_fx_image);
+	vcpu->interrupt_window_open = (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0;
 
 #ifndef CONFIG_X86_64
 	asm ("mov %0, %%ds; mov %0, %%es" : : "r"(__USER_DS));
@@ -1834,12 +1880,22 @@
 			/* Give scheduler a change to reschedule. */
 			if (signal_pending(current)) {
 				++kvm_stat.signal_exits;
+				post_kvm_run_save(vcpu, kvm_run);
 				return -EINTR;
 			}
+
+			if (dm_request_for_irq_injection(vcpu, kvm_run)) {
+				++kvm_stat.request_irq_exits;
+				post_kvm_run_save(vcpu, kvm_run);
+				return -EINTR;
+			}
+
 			kvm_resched(vcpu);
 			goto again;
 		}
 	}
+
+	post_kvm_run_save(vcpu, kvm_run);
 	return 0;
 }