diff --git a/usr.sbin/bhyve/aarch64/bhyverun_machdep.c b/usr.sbin/bhyve/aarch64/bhyverun_machdep.c
--- a/usr.sbin/bhyve/aarch64/bhyverun_machdep.c
+++ b/usr.sbin/bhyve/aarch64/bhyverun_machdep.c
@@ -183,7 +183,7 @@
 			set_config_value("uuid", optarg);
 			break;
 		case 'W':
-			set_config_bool("virtio_msix", false);
+			set_config_bool("virtio.msix", false);
 			break;
 		case 'h':
 			bhyve_usage(0);
@@ -191,6 +191,9 @@
 			bhyve_usage(1);
 		}
 	}
+
+	/* Handle backwards compatibility aliases in config options. */
+	bhyve_cfg_warn("virtio_msix", "virtio.msix", "virtio.msix");
 }
 
 void
diff --git a/usr.sbin/bhyve/amd64/bhyverun_machdep.c b/usr.sbin/bhyve/amd64/bhyverun_machdep.c
--- a/usr.sbin/bhyve/amd64/bhyverun_machdep.c
+++ b/usr.sbin/bhyve/amd64/bhyverun_machdep.c
@@ -250,7 +250,7 @@
 			set_config_bool("x86.strictmsr", false);
 			break;
 		case 'W':
-			set_config_bool("virtio_msix", false);
+			set_config_bool("virtio.msix", false);
 			break;
 		case 'x':
 			set_config_bool("x86.x2apic", true);
@@ -266,16 +266,9 @@
 	}
 
 	/* Handle backwards compatibility aliases in config options. */
-	if (get_config_value("lpc.bootrom") != NULL &&
-	    get_config_value("bootrom") == NULL) {
-		warnx("lpc.bootrom is deprecated, use '-o bootrom' instead");
-		set_config_value("bootrom", get_config_value("lpc.bootrom"));
-	}
-	if (get_config_value("lpc.bootvars") != NULL &&
-	    get_config_value("bootvars") == NULL) {
-		warnx("lpc.bootvars is deprecated, use '-o bootvars' instead");
-		set_config_value("bootvars", get_config_value("lpc.bootvars"));
-	}
+	bhyve_cfg_warn("lpc.bootrom", "bootrom", "-o bootrom");
+	bhyve_cfg_warn("lpc.bootvars", "bootvars", "-o bootvars");
+	bhyve_cfg_warn("virtio_msix", "virtio.msix", "virtio.msix");
 }
 
 void
diff --git a/usr.sbin/bhyve/bhyve_config.5 b/usr.sbin/bhyve/bhyve_config.5
--- a/usr.sbin/bhyve/bhyve_config.5
+++ b/usr.sbin/bhyve/bhyve_config.5
@@ -170,7 +170,7 @@
 System Management BIOS System Information structure.
 If an explicit value is not set, a valid UUID is generated from
 the host's hostname and the VM name.
-.It Va virtio_msix Ta bool Ta true Ta
+.It Va virtio.msix Ta bool Ta true Ta
 Use MSI-X interrupts for PCI VirtIO devices.
 If set to false, MSI interrupts are used instead.
 .It Va virtio.legacy Ta bool Ta true Ta
diff --git a/usr.sbin/bhyve/bhyverun.h b/usr.sbin/bhyve/bhyverun.h
--- a/usr.sbin/bhyve/bhyverun.h
+++ b/usr.sbin/bhyve/bhyverun.h
@@ -84,6 +84,7 @@
 int bhyve_pincpu_parse(const char *opt);
 int bhyve_topology_parse(const char *opt);
 int bhyve_numa_parse(const char *opt);
+void bhyve_cfg_warn(const char *old, const char *new, const char *msg);
 
 void bhyve_init_vcpu(struct vcpu *vcpu);
 void bhyve_start_vcpu(struct vcpu *vcpu, bool bsp);
diff --git a/usr.sbin/bhyve/bhyverun.c b/usr.sbin/bhyve/bhyverun.c
--- a/usr.sbin/bhyve/bhyverun.c
+++ b/usr.sbin/bhyve/bhyverun.c
@@ -242,6 +242,16 @@
 	return (-1);
 }
 
+void
+bhyve_cfg_warn(const char *old, const char *new, const char *msg)
+{
+	if (get_config_value(old) != NULL &&
+	    get_config_value(new) == NULL) {
+		warnx("'%s' is deprecated, use '%s' instead", old, msg);
+		set_config_value(new, get_config_value(old));
+	}
+}
+
 static void
 calc_mem_affinity(size_t vm_memsize)
 {
@@ -551,8 +561,7 @@
 int
 fbsdrun_virtio_msix(void)
 {
-
-	return (get_config_bool_default("virtio_msix", true));
+	return (get_config_bool_default("virtio.msix", true));
 }
 
 struct vcpu *
diff --git a/usr.sbin/bhyve/riscv/bhyverun_machdep.c b/usr.sbin/bhyve/riscv/bhyverun_machdep.c
--- a/usr.sbin/bhyve/riscv/bhyverun_machdep.c
+++ b/usr.sbin/bhyve/riscv/bhyverun_machdep.c
@@ -174,7 +174,7 @@
 			set_config_value("uuid", optarg);
 			break;
 		case 'W':
-			set_config_bool("virtio_msix", false);
+			set_config_bool("virtio.msix", false);
 			break;
 		case 'h':
 			bhyve_usage(0);
@@ -182,6 +182,10 @@
 			bhyve_usage(1);
 		}
 	}
+
+	/* Handle backwards compatibility aliases in config options. */
+	bhyve_cfg_warn("virtio_msix", "virtio.msix", "virtio.msix");
+
 }
 
 void