Index: sys/dev/nvmm/nvmm.c
===================================================================
RCS file: /cvsroot/src/sys/dev/nvmm/nvmm.c,v
retrieving revision 1.33
diff -u -r1.33 nvmm.c
--- sys/dev/nvmm/nvmm.c	1 Aug 2020 08:18:36 -0000	1.33
+++ sys/dev/nvmm/nvmm.c	5 Aug 2020 18:00:00 -0000
@@ -573,8 +573,7 @@
 
 	while (1) {
 		/* Got a signal? Or pending resched? Leave. */
-		if (__predict_false(nvmm_return_needed())) {
-			exit->reason = NVMM_VCPU_EXIT_NONE;
+		if (__predict_false(nvmm_return_needed(vcpu, exit))) {
 			return 0;
 		}
 
@@ -619,6 +618,7 @@
 
 out:
 	nvmm_machine_put(mach);
+	vcpu->comm->immediate_exit = false;
 	return error;
 }
 
Index: sys/dev/nvmm/nvmm.h
===================================================================
RCS file: /cvsroot/src/sys/dev/nvmm/nvmm.h,v
retrieving revision 1.13
diff -u -r1.13 nvmm.h
--- sys/dev/nvmm/nvmm.h	1 Aug 2020 08:18:36 -0000	1.13
+++ sys/dev/nvmm/nvmm.h	5 Aug 2020 18:00:00 -0000
@@ -48,7 +48,7 @@
 #include <dev/nvmm/x86/nvmm_x86.h>
 #endif
 
-#define NVMM_KERN_VERSION		1
+#define NVMM_KERN_VERSION		2
 
 struct nvmm_capability {
 	uint32_t version;
@@ -81,6 +81,9 @@
 	/* Event. */
 	bool event_commit;
 	struct nvmm_vcpu_event event;
+
+	/* Race-free exit from nvmm_vcpu_run() without signals. */
+	volatile bool immediate_exit;
 };
 
 /*
Index: sys/dev/nvmm/nvmm_internal.h
===================================================================
RCS file: /cvsroot/src/sys/dev/nvmm/nvmm_internal.h,v
retrieving revision 1.17
diff -u -r1.17 nvmm_internal.h
--- sys/dev/nvmm/nvmm_internal.h	1 Aug 2020 08:18:36 -0000	1.17
+++ sys/dev/nvmm/nvmm_internal.h	5 Aug 2020 18:00:00 -0000
@@ -125,14 +125,24 @@
 #endif
 
 static inline bool
-nvmm_return_needed(void)
+nvmm_return_needed(struct nvmm_cpu *vcpu, struct nvmm_vcpu_exit *exit)
 {
+
 	if (preempt_needed()) {
+		exit->reason = NVMM_VCPU_EXIT_NONE;
 		return true;
 	}
 	if (curlwp->l_flag & LW_USERRET) {
+		exit->reason = NVMM_VCPU_EXIT_NONE;
+		return true;
+	}
+	if (vcpu->comm->immediate_exit) {
+		vcpu->comm->immediate_exit = false;
+		exit->reason = NVMM_VCPU_EXIT_STOPPED;
+		printf("%s() %s:%d\n", __func__, __FILE__, __LINE__);
 		return true;
 	}
+
 	return false;
 }
 
Index: sys/dev/nvmm/x86/nvmm_x86.h
===================================================================
RCS file: /cvsroot/src/sys/dev/nvmm/x86/nvmm_x86.h,v
retrieving revision 1.18
diff -u -r1.18 nvmm_x86.h
--- sys/dev/nvmm/x86/nvmm_x86.h	28 Oct 2019 08:30:49 -0000	1.18
+++ sys/dev/nvmm/x86/nvmm_x86.h	5 Aug 2020 18:00:00 -0000
@@ -75,6 +75,7 @@
 
 /* Generic. */
 #define NVMM_VCPU_EXIT_NONE		0x0000000000000000ULL
+#define NVMM_VCPU_EXIT_STOPPED		0xFFFFFFFFFFFFFFFEULL
 #define NVMM_VCPU_EXIT_INVALID		0xFFFFFFFFFFFFFFFFULL
 /* x86: operations. */
 #define NVMM_VCPU_EXIT_MEMORY		0x0000000000000001ULL
Index: sys/dev/nvmm/x86/nvmm_x86_svm.c
===================================================================
RCS file: /cvsroot/src/sys/dev/nvmm/x86/nvmm_x86_svm.c,v
retrieving revision 1.65
diff -u -r1.65 nvmm_x86_svm.c
--- sys/dev/nvmm/x86/nvmm_x86_svm.c	19 Jul 2020 06:56:09 -0000	1.65
+++ sys/dev/nvmm/x86/nvmm_x86_svm.c	5 Aug 2020 18:00:00 -0000
@@ -1472,7 +1472,7 @@
 		}
 
 		/* If no reason to return to userland, keep rolling. */
-		if (nvmm_return_needed()) {
+		if (nvmm_return_needed(vcpu, exit)) {
 			break;
 		}
 		if (exit->reason != NVMM_VCPU_EXIT_NONE) {
Index: sys/dev/nvmm/x86/nvmm_x86_vmx.c
===================================================================
RCS file: /cvsroot/src/sys/dev/nvmm/x86/nvmm_x86_vmx.c,v
retrieving revision 1.65
diff -u -r1.65 nvmm_x86_vmx.c
--- sys/dev/nvmm/x86/nvmm_x86_vmx.c	19 Jul 2020 06:56:09 -0000	1.65
+++ sys/dev/nvmm/x86/nvmm_x86_vmx.c	5 Aug 2020 18:00:01 -0000
@@ -2195,7 +2195,7 @@
 		}
 
 		/* If no reason to return to userland, keep rolling. */
-		if (nvmm_return_needed()) {
+		if (nvmm_return_needed(vcpu, exit)) {
 			break;
 		}
 		if (exit->reason != NVMM_VCPU_EXIT_NONE) {
Index: lib/libnvmm/libnvmm.c
===================================================================
RCS file: /cvsroot/src/lib/libnvmm/libnvmm.c,v
retrieving revision 1.18
diff -u -r1.18 libnvmm.c
--- lib/libnvmm/libnvmm.c	27 Oct 2019 20:17:36 -0000	1.18
+++ lib/libnvmm/libnvmm.c	5 Aug 2020 18:00:42 -0000
@@ -311,6 +311,7 @@
 	vcpu->cpuid = cpuid;
 	vcpu->state = &comm->state;
 	vcpu->event = &comm->event;
+	vcpu->immediate_exit = &comm->immediate_exit;
 	vcpu->exit = malloc(sizeof(*vcpu->exit));
 
 	return 0;
@@ -562,3 +563,12 @@
 
 	return 0;
 }
+
+int
+nvmm_vcpu_stop(struct nvmm_vcpu *vcpu)
+{
+
+	vcpu->immediate_exit = true;
+
+	return 0;
+}
Index: lib/libnvmm/nvmm.h
===================================================================
RCS file: /cvsroot/src/lib/libnvmm/nvmm.h,v
retrieving revision 1.17
diff -u -r1.17 nvmm.h
--- lib/libnvmm/nvmm.h	28 Oct 2019 08:30:49 -0000	1.17
+++ lib/libnvmm/nvmm.h	5 Aug 2020 18:00:42 -0000
@@ -38,7 +38,12 @@
 #include <dev/nvmm/nvmm.h>
 #include <dev/nvmm/nvmm_ioctl.h>
 
-#define NVMM_USER_VERSION	1
+#define NVMM_USER_VERSION	2
+
+/*
+ * Version 1 - Initial release in NetBSD 9.0.
+ * Version 2 - Added nvmm_vcpu::immediate_exit.
+ */
 
 struct nvmm_io;
 struct nvmm_mem;
@@ -60,6 +65,7 @@
 	struct nvmm_vcpu_state *state;
 	struct nvmm_vcpu_event *event;
 	struct nvmm_vcpu_exit *exit;
+	volatile bool immediate_exit;
 };
 
 struct nvmm_io {
@@ -124,4 +130,6 @@
 
 int nvmm_vcpu_dump(struct nvmm_machine *, struct nvmm_vcpu *);
 
+int nvmm_vcpu_stop(struct nvmm_vcpu *);
+
 #endif /* _LIBNVMM_H_ */