Index: sys/amd64/vmm/io/vatpic.c
===================================================================
--- sys/amd64/vmm/io/vatpic.c	(revision 265126)
+++ sys/amd64/vmm/io/vatpic.c	(working copy)
@@ -694,3 +694,9 @@
 {
 	free(vatpic, M_VATPIC);
 }
+
+int
+vatpic_imcr_mode(struct vatpic *vatpic)
+{
+	return (1);	/* XXX */
+}
Index: sys/amd64/vmm/io/vatpic.h
===================================================================
--- sys/amd64/vmm/io/vatpic.h	(revision 265126)
+++ sys/amd64/vmm/io/vatpic.h	(working copy)
@@ -52,5 +52,6 @@
 
 void vatpic_pending_intr(struct vm *vm, int *vecptr);
 void vatpic_intr_accepted(struct vm *vm, int vector);
+int vatpic_imcr_mode(struct vatpic *vatpic);
 
 #endif	/* _VATPIC_H_ */
Index: sys/amd64/vmm/vmm.c
===================================================================
--- sys/amd64/vmm/vmm.c	(revision 265126)
+++ sys/amd64/vmm/vmm.c	(working copy)
@@ -142,6 +142,8 @@
 
 	int		suspend;
 	volatile cpuset_t suspended_cpus;
+
+	volatile cpuset_t halted_cpus;
 };
 
 static int vmm_initialized;
@@ -999,6 +1001,25 @@
 }
 
 /*
+ * VM exit collateral to fake an 'outb' to the AT keyboard I/O port. The value
+ * written will cause a virtual machine reset.
+ */
+static void
+vm_exit_atkbd_reset(struct vm *vm, int vcpuid)
+{
+	struct vm_exit *vmexit;
+
+	vmexit = vm_exitinfo(vm, vcpuid);
+	vmexit->exitcode = VM_EXITCODE_INOUT;
+	vmexit->u.inout.bytes = 1;
+	vmexit->u.inout.in = 0;
+	vmexit->u.inout.string = 0;
+	vmexit->u.inout.rep = 0;
+	vmexit->u.inout.port = 0x64;
+	vmexit->u.inout.eax = 0xFE;
+}
+
+/*
  * Emulate a guest 'hlt' by sleeping until the vcpu is ready to run.
  */
 static int
@@ -1006,9 +1027,13 @@
 {
 	struct vcpu *vcpu;
 	const char *wmesg;
-	int t;
+	int t, apic_mode, halted;
 
+	KASSERT(!CPU_ISSET(vcpuid, &vm->halted_cpus), ("vcpu already halted"));
+
 	vcpu = &vm->vcpu[vcpuid];
+	apic_mode = vatpic_imcr_mode(vm->vatpic);
+	halted = 0;
 
 	vcpu_lock(vcpu);
 	while (1) {
@@ -1032,10 +1057,27 @@
 			}
 		}
 
-		if (vlapic_enabled(vcpu->vlapic))
+		/*
+		 * Some Linux guests implement "halt" by having all vcpus
+		 * execute HLT with the APIC disabled. The 'halted_cpus' keep
+		 * track of the vcpus that have entered this state. When all
+		 * vcpus enter the halted state we trigger a VM reset.
+		 */
+		if (intr_disabled ||
+		    (apic_mode && !vlapic_enabled(vcpu->vlapic))) {
+			wmesg = "vmhalt";
+			if (!halted) {
+				halted = 1;
+				CPU_SET_ATOMIC(vcpuid, &vm->halted_cpus);
+			}
+			if (CPU_CMP(&vm->halted_cpus, &vm->active_cpus) == 0) {
+				*retu = true;
+				vm_exit_atkbd_reset(vm, vcpuid);
+				break;
+			}
+		} else {
 			wmesg = "vmidle";
-		else
-			wmesg = "vmhalt";
+		}
 
 		t = ticks;
 		vcpu_require_state_locked(vcpu, VCPU_SLEEPING);
@@ -1043,6 +1085,10 @@
 		vcpu_require_state_locked(vcpu, VCPU_FROZEN);
 		vmm_stat_incr(vm, vcpuid, VCPU_IDLE_TICKS, ticks - t);
 	}
+
+	if (halted)
+		CPU_CLR_ATOMIC(vcpuid, &vm->halted_cpus);
+
 	vcpu_unlock(vcpu);
 
 	return (0);