Index: sys/dev/mem/memdev.c
===================================================================
--- sys/dev/mem/memdev.c
+++ sys/dev/mem/memdev.c
@@ -32,6 +32,7 @@
 
 #include <sys/param.h>
 #include <sys/conf.h>
+#include <sys/disk.h>
 #include <sys/fcntl.h>
 #include <sys/ioccom.h>
 #include <sys/kernel.h>
@@ -99,6 +100,8 @@
 	vm_map_entry_t entry;
 	struct mem_extract *me;
 	int fd, error;
+	struct diocskerneldump_arg *conf;
+	uint8_t *encryptedkey;
 
 	error = 0;
 	switch (cmd) {
@@ -125,6 +128,36 @@
 		fd = *(int *)data;
 		error = livedump_start(fd);
 		break;
+	case DIOCSKERNELDUMP:
+		encryptedkey = NULL;
+		conf = (void *)data;
+		if (conf->kda_index == KDA_REMOVE ||
+		    conf->kda_index == KDA_REMOVE_DEV ||
+		    conf->kda_index == KDA_REMOVE_ALL) {
+			/* Nothing to do. */
+			return (0);
+		}
+		if (conf->kda_encryption != KERNELDUMP_ENC_NONE) {
+			if (conf->kda_encryptedkeysize <= 0 ||
+			    conf->kda_encryptedkeysize >
+			    KERNELDUMP_ENCKEY_MAX_SIZE) {
+				error = EINVAL;
+				break;
+			}
+			encryptedkey = malloc(conf->kda_encryptedkeysize,
+			    M_TEMP, M_WAITOK);
+			error = copyin(conf->kda_encryptedkey, encryptedkey,
+			    conf->kda_encryptedkeysize);
+			if (error != 0) {
+				free(encryptedkey, M_TEMP);
+				break;
+			}
+			conf->kda_encryptedkey = encryptedkey;
+		}
+
+		error = livedump_configure(conf);
+		free(encryptedkey, M_TEMP);
+		break;
 	default:
 		error = memioctl_md(dev, cmd, data, flags, td);
 		break;