6651197 Add support for LDoms Virtual I/O Dynamic Reconfiguration (VIO DR)

FWARC 2008/229 Virtual IO DR Domain Service

12 files changed, 1325 insertions, 30 deletions

diff --git a/usr/src/cmd/drd/drd.c b/usr/src/cmd/drd/drd.c
index a0c61c988e..a6e33f9237 100644
--- a/usr/src/cmd/drd/drd.c
+++ b/usr/src/cmd/drd/drd.c
@@ -20,7 +20,7 @@
  */
 
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -392,11 +392,19 @@ drd_door_server(void *cookie, char *argp, size_t arg_sz, door_desc_t *dp,
 		break;
 
 	case DRCTL_IO_CONFIG_REQUEST:
+		(*drd_backend->io_config_request)(rsrcs, nrsrc);
+		break;
+
 	case DRCTL_IO_CONFIG_NOTIFY:
+		(*drd_backend->io_config_notify)(rsrcs, nrsrc);
+		break;
+
 	case DRCTL_IO_UNCONFIG_REQUEST:
+		(*drd_backend->io_unconfig_request)(rsrcs, nrsrc);
+		break;
+
 	case DRCTL_IO_UNCONFIG_NOTIFY:
-		drd_err("I/O DR operations not supported yet");
-		DRD_DOOR_RETURN_ERR();
+		(*drd_backend->io_unconfig_notify)(rsrcs, nrsrc);
 		break;
 
 	default:
diff --git a/usr/src/cmd/drd/drd.h b/usr/src/cmd/drd/drd.h
index 2743efd25b..bf8efe3b07 100644
--- a/usr/src/cmd/drd/drd.h
+++ b/usr/src/cmd/drd/drd.h
@@ -20,7 +20,7 @@
  */
 
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -61,6 +61,10 @@ typedef struct {
 	int (*cpu_config_notify)(drctl_rsrc_t *rsrcs, int nrsrc);
 	int (*cpu_unconfig_request)(drctl_rsrc_t *rsrcs, int nrsrc);
 	int (*cpu_unconfig_notify)(drctl_rsrc_t *rsrcs, int nrsrc);
+	int (*io_config_request)(drctl_rsrc_t *rsrc, int nrsrc);
+	int (*io_config_notify)(drctl_rsrc_t *rsrc, int nrsrc);
+	int (*io_unconfig_request)(drctl_rsrc_t *rsrc, int nrsrc);
+	int (*io_unconfig_notify)(drctl_rsrc_t *rsrc, int nrsrc);
 } drd_backend_t;
 
 extern drd_backend_t drd_rcm_backend;
diff --git a/usr/src/cmd/drd/drd_rcm.c b/usr/src/cmd/drd/drd_rcm.c
index 5f16ef1c7b..cdee9840e7 100644
--- a/usr/src/cmd/drd/drd_rcm.c
+++ b/usr/src/cmd/drd/drd_rcm.c
@@ -20,7 +20,7 @@
  */
 
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -36,6 +36,7 @@
 #include <kstat.h>
 #include <libnvpair.h>
 #include <librcm.h>
+#include <locale.h>
 
 #include "drd.h"
 
@@ -48,6 +49,10 @@ static int drd_rcm_cpu_config_request(drctl_rsrc_t *rsrcs, int nrsrc);
 static int drd_rcm_cpu_config_notify(drctl_rsrc_t *rsrcs, int nrsrc);
 static int drd_rcm_cpu_unconfig_request(drctl_rsrc_t *rsrcs, int nrsrc);
 static int drd_rcm_cpu_unconfig_notify(drctl_rsrc_t *rsrcs, int nrsrc);
+static int drd_rcm_io_config_request(drctl_rsrc_t *rsrc, int nrsrc);
+static int drd_rcm_io_config_notify(drctl_rsrc_t *rsrc, int nrsrc);
+static int drd_rcm_io_unconfig_request(drctl_rsrc_t *rsrc, int nrsrc);
+static int drd_rcm_io_unconfig_notify(drctl_rsrc_t *rsrc, int nrsrc);
 
 drd_backend_t drd_rcm_backend = {
 	drd_rcm_init,			/* init */
@@ -55,7 +60,11 @@ drd_backend_t drd_rcm_backend = {
 	drd_rcm_cpu_config_request,	/* cpu_config_request */
 	drd_rcm_cpu_config_notify,	/* cpu_config_notify */
 	drd_rcm_cpu_unconfig_request,	/* cpu_unconfig_request */
-	drd_rcm_cpu_unconfig_notify	/* cpu_unconfig_notify */
+	drd_rcm_cpu_unconfig_notify,	/* cpu_unconfig_notify */
+	drd_rcm_io_config_request,	/* io_config_request */
+	drd_rcm_io_config_notify,	/* io_config_notify */
+	drd_rcm_io_unconfig_request,	/* io_unconfig_request */
+	drd_rcm_io_unconfig_notify	/* io_unconfig_notify */
 };
 
 #define	RCM_CPU_ALL		"SUNW_cpu"
@@ -80,6 +89,7 @@ static void drd_rcm_cpu_rlist_fini(char **rlist);
 static drctl_rsrc_t *cpu_rsrcstr_to_rsrc(const char *, drctl_rsrc_t *, int);
 static int get_sys_cpuids(cpuid_t **cpuids, int *ncpuids);
 static boolean_t is_cpu_in_list(cpuid_t cpuid, cpuid_t *list, int len);
+static char *rcm_info_table(rcm_info_t *rinfo);
 
 /* debugging utility functions */
 static void dump_cpu_list(char *prefix, cpuid_t *cpuids, int ncpuids);
@@ -123,7 +133,7 @@ drd_rcm_cpu_config_request(drctl_rsrc_t *rsrcs, int nrsrc)
 
 	/*
 	 * There is no RCM operation to request the addition
-	 * of resources. So, by definition, the operation for
+	 * of resources.  So, by definition, the operation for
 	 * all the CPUs is allowed.
 	 */
 	for (idx = 0; idx < nrsrc; idx++)
@@ -988,3 +998,203 @@ dump_cpu_rlist(char **rlist)
 		    rlist[idx], state, rcm_state_str[state]);
 	}
 }
+
+static int
+drd_rcm_io_config_request(drctl_rsrc_t *rsrc, int nrsrc)
+{
+	drd_dbg("drd_rcm_io_config_request...");
+
+	if (nrsrc != 1) {
+		drd_dbg("drd_rcm_cpu_config_request: only 1 resource "
+		    "allowed for I/O requests, passed %d resources\n", nrsrc);
+		rsrc->status = DRCTL_STATUS_DENY;
+
+		return (-1);
+	}
+
+	/*
+	 * There is no RCM operation to request the addition
+	 * of resources.  So, by definition, the operation for
+	 * the current resource is allowed.
+	 */
+	rsrc->status = DRCTL_STATUS_ALLOW;
+
+	return (0);
+}
+
+/*ARGSUSED*/
+static int
+drd_rcm_io_config_notify(drctl_rsrc_t *rsrcs, int nrsrc)
+{
+	drd_dbg("drd_rcm_io_config_notify...");
+
+	if (nrsrc != 1) {
+		drd_dbg("drd_rcm_cpu_config_notify: only 1 resource "
+		    "allowed for I/O requests, passed %d resources\n", nrsrc);
+
+		return (-1);
+	}
+
+	return (0);
+}
+
+
+static int
+drd_rcm_io_unconfig_request(drctl_rsrc_t *rsrc, int nrsrc)
+{
+	int		rv;
+	char		*dev = rsrc->res_dev_path;
+	rcm_info_t	*rinfo = NULL;
+
+	if (nrsrc != 1) {
+		drd_dbg("drd_io_unconfig_request: only 1 resource "
+		    "allowed for I/O requests, passed %d resources\n", nrsrc);
+		rsrc->status = DRCTL_STATUS_DENY;
+
+		return (-1);
+	}
+
+	if ((rv = rcm_request_offline(rcm_hdl, dev, 0, &rinfo)) == RCM_SUCCESS)
+		rsrc->status = DRCTL_STATUS_ALLOW;
+	else {
+		rcm_notify_online(rcm_hdl, dev, 0, NULL);
+		rsrc->status = DRCTL_STATUS_DENY;
+		rsrc->offset = (uintptr_t)rcm_info_table(rinfo);
+
+	}
+
+	rcm_free_info(rinfo);
+	drd_dbg("drd_rcm_io_unconfig_request(%s) = %d", dev, rv);
+
+	return (rv);
+}
+
+static int
+drd_rcm_io_unconfig_notify(drctl_rsrc_t *rsrc, int nrsrc)
+{
+	drd_dbg("drd_rcm_io_unconfig_notify...");
+
+	if (nrsrc != 1) {
+		drd_dbg("drd_io_cpu_unconfig_notify: only 1 resource "
+		    "allowed for I/O requests, passed %d resources\n", nrsrc);
+
+		return (-1);
+	}
+
+	return (rcm_notify_remove(rcm_hdl, rsrc->res_dev_path, 0, NULL));
+}
+
+#define	MAX_FORMAT	80
+
+/*
+ * Convert rcm_info_t data into a printable table.
+ */
+static char *
+rcm_info_table(rcm_info_t *rinfo)
+{
+	int		i;
+	size_t		w;
+	size_t		width = 0;
+	size_t		w_rsrc = 0;
+	size_t		w_info = 0;
+	size_t		table_size = 0;
+	uint_t		tuples = 0;
+	rcm_info_tuple_t *tuple = NULL;
+	char		*rsrc;
+	char		*info;
+	char		*table;
+	static char	format[MAX_FORMAT];
+	const char	*infostr;
+
+	/* Protect against invalid arguments */
+	if (rinfo == NULL)
+		return (NULL);
+
+	/* Set localized table header strings */
+	rsrc = dgettext(TEXT_DOMAIN, "Resource");
+	info = dgettext(TEXT_DOMAIN, "Information");
+
+	/* A first pass, to size up the RCM information */
+	while (tuple = rcm_info_next(rinfo, tuple)) {
+		if ((infostr = rcm_info_info(tuple)) != NULL) {
+			tuples++;
+			if ((w = strlen(rcm_info_rsrc(tuple))) > w_rsrc)
+				w_rsrc = w;
+			if ((w = strlen(infostr)) > w_info)
+				w_info = w;
+		}
+	}
+
+	/* If nothing was sized up above, stop early */
+	if (tuples == 0)
+		return (NULL);
+
+	/* Adjust column widths for column headings */
+	if ((w = strlen(rsrc)) > w_rsrc)
+		w_rsrc = w;
+	else if ((w_rsrc - w) % 2)
+		w_rsrc++;
+	if ((w = strlen(info)) > w_info)
+		w_info = w;
+	else if ((w_info - w) % 2)
+		w_info++;
+
+	/*
+	 * Compute the total line width of each line,
+	 * accounting for intercolumn spacing.
+	 */
+	width = w_info + w_rsrc + 4;
+
+	/* Allocate space for the table */
+	table_size = (2 + tuples) * (width + 1) + 2;
+
+	/* zero fill for the strcat() call below */
+	table = calloc(table_size, sizeof (char));
+	if (table == NULL)
+		return (NULL);
+
+	/* Place a table header into the string */
+
+	/* The resource header */
+	(void) strcat(table, "\n");
+	w = strlen(rsrc);
+	for (i = 0; i < ((w_rsrc - w) / 2); i++)
+		(void) strcat(table, " ");
+	(void) strcat(table, rsrc);
+	for (i = 0; i < ((w_rsrc - w) / 2); i++)
+		(void) strcat(table, " ");
+
+	/* The information header */
+	(void) strcat(table, "  ");
+	w = strlen(info);
+	for (i = 0; i < ((w_info - w) / 2); i++)
+		(void) strcat(table, " ");
+	(void) strcat(table, info);
+	for (i = 0; i < ((w_info - w) / 2); i++)
+		(void) strcat(table, " ");
+	/* Underline the headers */
+	(void) strcat(table, "\n");
+	for (i = 0; i < w_rsrc; i++)
+		(void) strcat(table, "-");
+	(void) strcat(table, "  ");
+	for (i = 0; i < w_info; i++)
+		(void) strcat(table, "-");
+
+	/* Construct the format string */
+	(void) snprintf(format, MAX_FORMAT, "%%-%ds  %%-%ds",
+	    (int)w_rsrc, (int)w_info);
+
+	/* Add the tuples to the table string */
+	tuple = NULL;
+	while ((tuple = rcm_info_next(rinfo, tuple)) != NULL) {
+		if ((infostr = rcm_info_info(tuple)) != NULL) {
+			(void) strcat(table, "\n");
+			(void) sprintf(&((table)[strlen(table)]),
+			    format, rcm_info_rsrc(tuple),
+			    infostr);
+		}
+	}
+	drd_dbg("rcm_info_table: %s\n", table);
+
+	return (table);
+}
diff --git a/usr/src/pkgdefs/SUNWldomr.v/prototype_sparc b/usr/src/pkgdefs/SUNWldomr.v/prototype_sparc
index 6e7aac0b63..825734cc4a 100644
--- a/usr/src/pkgdefs/SUNWldomr.v/prototype_sparc
+++ b/usr/src/pkgdefs/SUNWldomr.v/prototype_sparc
@@ -20,7 +20,7 @@
 #
 
 #
-# Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+# Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 # Use is subject to license terms.
 #
 # ident	"%Z%%M%	%I%	%E% SMI"
@@ -74,6 +74,7 @@ f none platform/sun4v/kernel/drv/sparcv9/vsw 755 root sys
 d none platform/sun4v/kernel/misc 755 root sys
 d none platform/sun4v/kernel/misc/sparcv9 755 root sys
 f none platform/sun4v/kernel/misc/sparcv9/dr_cpu 755 root sys
+f none platform/sun4v/kernel/misc/sparcv9/dr_io 755 root sys
 f none platform/sun4v/kernel/misc/sparcv9/ds 755 root sys
 f none platform/sun4v/kernel/misc/sparcv9/fault_iso 755 root sys
 f none platform/sun4v/kernel/misc/sparcv9/ldc 755 root sys
diff --git a/usr/src/uts/sun4v/Makefile.files b/usr/src/uts/sun4v/Makefile.files
index 2d6bbad4a3..135e3110c0 100644
--- a/usr/src/uts/sun4v/Makefile.files
+++ b/usr/src/uts/sun4v/Makefile.files
@@ -164,6 +164,7 @@ DS_SNMP_OBJS	= ds_snmp.o
 #
 BOOTDEV_OBJS	+= bootdev.o
 DR_CPU_OBJS	+= dr_cpu.o
+DR_IO_OBJS	+= dr_io.o
 DRCTL_OBJS	= drctl.o drctl_impl.o dr_util.o
 DS_OBJS		= ds.o
 FAULT_ISO_OBJS	= fault_iso.o
diff --git a/usr/src/uts/sun4v/Makefile.sun4v.shared b/usr/src/uts/sun4v/Makefile.sun4v.shared
index 1df7f3ca83..b5b86bca12 100644
--- a/usr/src/uts/sun4v/Makefile.sun4v.shared
+++ b/usr/src/uts/sun4v/Makefile.sun4v.shared
@@ -390,6 +390,7 @@ SYS_KMODS	+=
 #
 MISC_KMODS	+= bootdev
 MISC_KMODS	+= dr_cpu
+MISC_KMODS	+= dr_io
 MISC_KMODS	+= ds
 MISC_KMODS	+= fault_iso
 MISC_KMODS	+= ldc
diff --git a/usr/src/uts/sun4v/dr_io/Makefile b/usr/src/uts/sun4v/dr_io/Makefile
new file mode 100644
index 0000000000..37ecb9fc06
--- /dev/null
+++ b/usr/src/uts/sun4v/dr_io/Makefile
@@ -0,0 +1,93 @@
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+# ident	"%Z%%M%	%I%	%E% SMI"
+#
+
+#
+# Path to the base of the uts directory tree (usually /usr/src/uts).
+#
+UTSBASE	= ../..
+
+#
+# Define the module and object file sets.
+#
+MODULE		= dr_io
+OBJECTS		= $(DR_IO_OBJS:%=$(OBJS_DIR)/%)
+LINTS		= $(DR_IO_OBJS:%.o=$(LINTS_DIR)/%.ln)
+ROOTMODULE	= $(ROOT_PSM_MISC_DIR)/$(MODULE)
+
+#
+# Include common rules.
+#
+include $(UTSBASE)/sun4v/Makefile.sun4v
+
+#
+# Define targets
+#
+ALL_TARGET	= $(BINARY)
+LINT_TARGET	= $(MODULE).lint
+INSTALL_TARGET	= $(BINARY) $(ROOTMODULE)
+
+#
+# lint pass one enforcement
+#
+CFLAGS		+= $(CCVERBOSE)
+
+#
+# Turn on doubleword alignment for 64 bit registers
+#
+CFLAGS		+= -dalign
+
+#
+# Module Dependencies
+#
+LDFLAGS		+= -dy -Nmisc/ds -Ndrv/drctl
+
+#
+# Default build targets.
+#
+.KEEP_STATE:
+
+def:		$(DEF_DEPS)
+
+all:		$(ALL_DEPS)
+
+clean:		$(CLEAN_DEPS)
+
+clobber:	$(CLOBBER_DEPS)
+
+lint:		$(LINT_DEPS)
+
+modlintlib:	$(MODLINTLIB_DEPS)
+
+clean.lint:	$(CLEAN_LINT_DEPS)
+
+install:	$(INSTALL_DEPS)
+
+#
+# Include common targets.
+#
+include $(UTSBASE)/$(PLATFORM)/Makefile.targ
diff --git a/usr/src/uts/sun4v/io/dr_io.c b/usr/src/uts/sun4v/io/dr_io.c
new file mode 100644
index 0000000000..64cd9a46b7
--- /dev/null
+++ b/usr/src/uts/sun4v/io/dr_io.c
@@ -0,0 +1,872 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+/*
+ * sun4v VIO DR Module
+ */
+
+#include <sys/modctl.h>
+#include <sys/sunddi.h>
+#include <sys/sunndi.h>
+#include <sys/note.h>
+#include <sys/sysevent/dr.h>
+#include <sys/hypervisor_api.h>
+#include <sys/mach_descrip.h>
+#include <sys/mdesc.h>
+#include <sys/mdesc_impl.h>
+#include <sys/ds.h>
+#include <sys/drctl.h>
+#include <sys/dr_util.h>
+#include <sys/dr_io.h>
+#include <sys/promif.h>
+#include <sys/machsystm.h>
+#include <sys/ethernet.h>
+#include <sys/hotplug/pci/pcicfg.h>
+
+
+static struct modlmisc modlmisc = {
+	&mod_miscops,
+	"sun4v VIO DR %I%"
+};
+
+static struct modlinkage modlinkage = {
+	MODREV_1,
+	(void *)&modlmisc,
+	NULL
+};
+
+
+/*
+ * VIO DS Interface
+ */
+
+/*
+ * Global DS Handle
+ */
+static ds_svc_hdl_t ds_vio_handle;
+
+/*
+ * Supported DS Capability Versions
+ */
+static ds_ver_t		dr_vio_vers[] = { { 1, 0 } };
+#define	DR_VIO_NVERS	(sizeof (dr_vio_vers) / sizeof (dr_vio_vers[0]))
+
+/*
+ * DS Capability Description
+ */
+static ds_capability_t dr_vio_cap = {
+	DR_VIO_DS_ID,		/* svc_id */
+	dr_vio_vers,		/* vers */
+	DR_VIO_NVERS		/* nvers */
+};
+
+/*
+ * DS Callbacks
+ */
+static void dr_vio_reg_handler(ds_cb_arg_t, ds_ver_t *, ds_svc_hdl_t);
+static void dr_vio_unreg_handler(ds_cb_arg_t arg);
+static void dr_vio_data_handler(ds_cb_arg_t arg, void *buf, size_t buflen);
+
+/*
+ * DS Client Ops Vector
+ */
+static ds_clnt_ops_t dr_vio_ops = {
+	dr_vio_reg_handler,	/* ds_reg_cb */
+	dr_vio_unreg_handler,	/* ds_unreg_cb */
+	dr_vio_data_handler,	/* ds_data_cb */
+	NULL			/* cb_arg */
+};
+
+
+typedef struct {
+	char		*name;
+	uint64_t	devid;
+	dev_info_t	*dip;
+} dr_search_arg_t;
+
+static int
+dr_io_check_node(dev_info_t *dip, void *arg)
+{
+	char 		*name;
+	uint64_t	devid;
+	dr_search_arg_t	*sarg = (dr_search_arg_t *)arg;
+
+	name = ddi_node_name(dip);
+
+	if (strcmp(name, sarg->name) != 0)
+		return (DDI_WALK_CONTINUE);
+
+	devid = ddi_prop_get_int(DDI_DEV_T_ANY, dip, DDI_PROP_DONTPASS,
+	    "reg", -1);
+
+	DR_DBG_IO("%s: found devid=%ld, looking for %ld\n",
+	    __func__, devid, sarg->devid);
+
+	if (devid == sarg->devid) {
+		DR_DBG_IO("%s: matched", __func__);
+
+		/* matching node must be returned held */
+		if (!e_ddi_branch_held(dip))
+			e_ddi_branch_hold(dip);
+
+		sarg->dip = dip;
+		return (DDI_WALK_TERMINATE);
+	}
+
+	return (DDI_WALK_CONTINUE);
+}
+
+/*
+ * Walk the device tree to find the dip corresponding to the devid
+ * passed in. If present, the dip is returned held. The caller must
+ * release the hold on the dip once it is no longer required. If no
+ * matching node if found, NULL is returned.
+ */
+static dev_info_t *
+dr_io_find_node(char *name, uint64_t devid)
+{
+	dr_search_arg_t	arg;
+
+	DR_DBG_IO("dr_io_find_node...\n");
+
+	arg.name = name;
+	arg.devid = devid;
+	arg.dip = NULL;
+
+	ddi_walk_devs(ddi_root_node(), dr_io_check_node, &arg);
+
+	ASSERT((arg.dip == NULL) || (e_ddi_branch_held(arg.dip)));
+
+	return ((arg.dip) ? arg.dip : NULL);
+}
+
+/*
+ * Look up a particular IO node in the MD. Returns the mde_cookie_t
+ * representing that IO node if present, and MDE_INVAL_ELEM_COOKIE otherwise.
+ * It is assumed the scratch array has already been allocated so that
+ * it can accommodate the worst case scenario, every node in the MD.
+ */
+static mde_cookie_t
+dr_io_find_node_md(md_t *mdp, char *name, uint64_t id, mde_cookie_t *listp)
+{
+	int		i;
+	int		nnodes;
+	char		*devnm;
+	uint64_t	devid;
+	mde_cookie_t	rootnode;
+	mde_cookie_t	result = MDE_INVAL_ELEM_COOKIE;
+
+	DR_DBG_IO("%s: %s@%ld\n", __func__, name, id);
+
+	rootnode = md_root_node(mdp);
+	ASSERT(rootnode != MDE_INVAL_ELEM_COOKIE);
+
+	/*
+	 * Scan the DAG for all candidate nodes.
+	 */
+	nnodes = md_scan_dag(mdp, rootnode, md_find_name(mdp, "virtual-device"),
+	    md_find_name(mdp, "fwd"), listp);
+
+	if (nnodes < 0) {
+		DR_DBG_IO("%s: scan for "
+		    "'virtual-device' nodes failed\n", __func__);
+		return (result);
+	}
+
+	DR_DBG_IO("%s: found %d nodes in the MD\n", __func__, nnodes);
+
+	/*
+	 * Find the node of interest
+	 */
+	for (i = 0; i < nnodes; i++) {
+
+		if (md_get_prop_str(mdp, listp[i], "name", &devnm)) {
+			DR_DBG_IO("%s: missing 'name' property for"
+			    " IO node %d\n", __func__, i);
+			return (DDI_WALK_ERROR);
+		}
+
+		if (strcmp(devnm, name) != 0)
+			continue;
+
+		if (md_get_prop_val(mdp, listp[i], "cfg-handle", &devid)) {
+			DR_DBG_IO("%s: missing 'cfg-handle' property for"
+			    " IO node %d\n", __func__, i);
+			break;
+		}
+
+		if (devid == id) {
+			/* found a match */
+			DR_DBG_IO("%s: found IO node %s@%ld "
+			    "in MD\n", __func__, name, id);
+			result = listp[i];
+			break;
+		}
+	}
+
+	if (result == MDE_INVAL_ELEM_COOKIE)
+		DR_DBG_IO("%s: IO node %ld not in MD\n", __func__, id);
+
+	return (result);
+}
+
+typedef struct {
+	md_t		*mdp;
+	mde_cookie_t	node;
+	dev_info_t	*dip;
+} cb_arg_t;
+
+#define	STR_ARR_LEN	5
+
+static int
+new_dev_node(dev_info_t *new_node, void *arg, uint_t flags)
+{
+	_NOTE(ARGUNUSED(flags))
+
+	cb_arg_t	*cba;
+	char		*devnm, *devtype;
+	char		*compat;
+	uint64_t	devid;
+	int		len = 0;
+	char		*curr;
+	int		i = 0;
+	char		*str_arr[STR_ARR_LEN];
+
+	cba = (cb_arg_t *)arg;
+
+	/*
+	 * Add 'name' property
+	 */
+	if (md_get_prop_str(cba->mdp, cba->node, "name", &devnm)) {
+		DR_DBG_IO("%s: failed to read 'name' prop from MD\n", __func__);
+		return (DDI_WALK_ERROR);
+	}
+	DR_DBG_IO("%s: device name is %s\n", __func__, devnm);
+
+	if (ndi_prop_update_string(DDI_DEV_T_NONE, new_node,
+	    "name", devnm) != DDI_SUCCESS) {
+		DR_DBG_IO("%s: failed to create 'name' prop\n", __func__);
+		return (DDI_WALK_ERROR);
+	}
+
+	/*
+	 * Add 'compatible' property
+	 */
+	if (md_get_prop_data(cba->mdp, cba->node, "compatible",
+	    (uint8_t **)&compat, &len)) {
+		DR_DBG_IO("%s: failed to read "
+		    "'compatible' prop from MD\n", __func__);
+		return (DDI_WALK_ERROR);
+	}
+
+	/* parse the MD string array */
+	curr = compat;
+	while (curr < (compat + len)) {
+
+		DR_DBG_IO("%s: adding '%s' to "
+		    "'compatible' prop\n", __func__, curr);
+
+		str_arr[i++] = curr;
+		curr += strlen(curr) + 1;
+
+		if (i == STR_ARR_LEN) {
+			DR_DBG_CPU("exceeded str_arr len (%d)\n", STR_ARR_LEN);
+			break;
+		}
+	}
+
+
+	if (ndi_prop_update_string_array(DDI_DEV_T_NONE, new_node,
+	    "compatible", str_arr, i) != DDI_SUCCESS) {
+		DR_DBG_IO("%s: cannot create 'compatible' prop\n", __func__);
+		return (DDI_WALK_ERROR);
+	}
+
+	/*
+	 * Add 'device_type' property
+	 */
+	if (md_get_prop_str(cba->mdp, cba->node, "device-type", &devtype)) {
+		DR_DBG_IO("%s: failed to read "
+		    "'device-type' prop from MD\n", __func__);
+		return (DDI_WALK_ERROR);
+	}
+	if (ndi_prop_update_string(DDI_DEV_T_NONE, new_node,
+	    "device_type", devtype) != DDI_SUCCESS) {
+		DR_DBG_IO("%s: failed to create "
+		    "'device-type' prop\n", __func__);
+		return (DDI_WALK_ERROR);
+	}
+
+	DR_DBG_IO("%s: device type is %s\n", __func__, devtype);
+
+	/*
+	 * Add 'reg' (cfg-handle) property
+	 */
+	if (md_get_prop_val(cba->mdp, cba->node, "cfg-handle", &devid)) {
+		DR_DBG_IO("%s: failed to read "
+		    "'cfg-handle' prop from MD\n", __func__);
+		return (DDI_WALK_ERROR);
+	}
+
+	DR_DBG_IO("%s: new device is %s@%ld\n", __func__, devnm, devid);
+
+	if (ndi_prop_update_int(DDI_DEV_T_NONE, new_node, "reg", devid)
+	    != DDI_SUCCESS) {
+		DR_DBG_IO("%s: failed to create 'reg' prop\n", __func__);
+		return (DDI_WALK_ERROR);
+	}
+
+	/* if vnet/vswitch, probe and add mac-address and mtu properties */
+	if (strcmp(devnm, "vsw") == 0 || strcmp(devnm, "network") == 0) {
+
+		int i, j;
+		uint64_t mtu, macaddr;
+		uchar_t maddr_arr[ETHERADDRL];
+
+		if (md_get_prop_val(cba->mdp, cba->node, "local-mac-address",
+		    &macaddr)) {
+			DR_DBG_IO("%s: failed to read "
+			    "'local-mac-address' prop from MD\n", __func__);
+			return (DDI_WALK_ERROR);
+		}
+
+		for (i = 0, j = (ETHERADDRL - 1); i < ETHERADDRL; i++, j--)
+			maddr_arr[j] = (macaddr >> (i * 8)) & 0xff;
+
+		if (ndi_prop_update_byte_array(DDI_DEV_T_NONE, new_node,
+		    "local-mac-address", maddr_arr, ETHERADDRL)
+		    != DDI_SUCCESS) {
+			DR_DBG_IO("%s: failed to create "
+			    "'local-mac-address' prop\n", __func__);
+			return (DDI_WALK_ERROR);
+		}
+
+		if (md_get_prop_val(cba->mdp, cba->node, "mtu", &mtu)) {
+			DR_DBG_IO("%s: failed to read "
+			    "'mtu' prop from MD\n", __func__);
+			return (DDI_WALK_ERROR);
+		}
+
+		if (ndi_prop_update_int64(DDI_DEV_T_NONE, new_node, "mtu",
+		    mtu) != DDI_SUCCESS) {
+			DR_DBG_IO("%s: failed to "
+			    "create 'mtu' prop\n", __func__);
+			return (DDI_WALK_ERROR);
+		}
+
+		DR_DBG_IO("%s: Added properties for %s@%ld, "
+		    "mac=%ld, mtu=%ld\n", __func__, devnm, devid, macaddr, mtu);
+	}
+
+	cba->dip = new_node;
+
+	return (DDI_WALK_TERMINATE);
+}
+
+/*
+ * Find the parent node of the argument virtual device node in
+ * the MD.  For virtual devices, the parent is always
+ * "channel-devices", so scan the MD using the "back" arcs
+ * looking for a node with that name.
+ */
+static mde_cookie_t
+dr_vio_find_parent_md(md_t *mdp, mde_cookie_t node)
+{
+	int		max_nodes;
+	int		num_nodes;
+	int		listsz;
+	mde_cookie_t    *listp;
+	mde_cookie_t	pnode = MDE_INVAL_ELEM_COOKIE;
+
+	max_nodes = md_node_count(mdp);
+	listsz = max_nodes * sizeof (mde_cookie_t);
+	listp = kmem_zalloc(listsz, KM_SLEEP);
+
+	num_nodes = md_scan_dag(mdp, node,
+	    md_find_name(mdp, "channel-devices"),
+	    md_find_name(mdp, "back"), listp);
+
+	ASSERT(num_nodes == 1);
+
+	if (num_nodes == 1)
+		pnode = listp[0];
+
+	kmem_free(listp, listsz);
+
+	return (pnode);
+}
+
+static int
+dr_io_configure(dr_vio_req_t *req, dr_vio_res_t *res)
+{
+	int		rv = ENXIO;
+	int		listsz;
+	int		nnodes;
+	uint64_t	devid = req->dev_id;
+	uint64_t	pdevid;
+	char		*name = req->name;
+	char		*pname;
+	md_t		*mdp = NULL;
+	mde_cookie_t	*listp = NULL;
+	mde_cookie_t	node;
+	mde_cookie_t	pnode;
+	dev_info_t	*pdip = NULL;
+	dev_info_t	*dip;
+	devi_branch_t	br;
+	cb_arg_t	cba;
+	int		drctl_cmd;
+	int		drctl_flags = 0;
+	drctl_rsrc_t	*drctl_req;
+	size_t		drctl_req_len;
+	drctl_rsrc_t	*drctl_res = NULL;
+	size_t		drctl_res_len = 0;
+	drctl_cookie_t	drctl_res_ck;
+	char		*p;
+	size_t		reason_len;
+
+	res->result = DR_VIO_RES_FAILURE;
+
+	if ((dip = dr_io_find_node(name, devid)) != NULL) {
+		DR_DBG_IO("%s: %s@%ld already configured\n",
+		    __func__, name, devid);
+
+		/* Return success if resources is already there. */
+		res->result = DR_VIO_RES_OK;
+		res->status = DR_VIO_STAT_CONFIGURED;
+		e_ddi_branch_rele(dip);
+		return (0);
+	}
+
+	/* Assume we fail to find the node to be added. */
+	res->status = DR_VIO_STAT_NOT_PRESENT;
+
+	if ((mdp = md_get_handle()) == NULL) {
+		DR_DBG_IO("%s: unable to initialize MD\n", __func__);
+		return (ENXIO);
+	}
+
+	nnodes = md_node_count(mdp);
+	ASSERT(nnodes > 0);
+
+	listsz = nnodes * sizeof (mde_cookie_t);
+	listp = kmem_zalloc(listsz, KM_SLEEP);
+
+	/*
+	 * Get the MD device node.
+	 */
+	node = dr_io_find_node_md(mdp, name, devid, listp);
+
+	if (node == MDE_INVAL_ELEM_COOKIE) {
+		DR_DBG_IO("%s: scan for %s name node failed\n", __func__, name);
+		res->result = DR_VIO_RES_NOT_IN_MD;
+		goto done;
+	}
+
+	/*
+	 * Get the MD parent node.
+	 */
+	pnode = dr_vio_find_parent_md(mdp, node);
+	if (pnode == MDE_INVAL_ELEM_COOKIE) {
+		DR_DBG_IO("%s: failed to find MD parent of %lx\n",
+		    __func__, pnode);
+		goto done;
+	}
+
+	if (md_get_prop_str(mdp, pnode, "name", &pname)) {
+		DR_DBG_IO("%s: failed to read "
+		    "'name' for pnode %lx from MD\n", __func__, pnode);
+		goto done;
+	}
+
+	if (md_get_prop_val(mdp, pnode, "cfg-handle", &pdevid)) {
+		DR_DBG_IO("%s: failed to read 'cfg-handle' "
+		    "for pnode '%s' from MD\n", __func__, pname);
+		goto done;
+	}
+
+	DR_DBG_IO("%s: parent device %s@%lx\n", __func__, pname, pdevid);
+
+	/*
+	 * Get the devinfo parent node.
+	 */
+	if ((pdip = dr_io_find_node(pname, pdevid)) == NULL) {
+		DR_DBG_IO("%s: parent device %s@%ld not found\n",
+		    __func__, pname, pdevid);
+		goto done;
+	}
+
+	drctl_req_len = sizeof (drctl_rsrc_t) + MAXPATHLEN;
+	drctl_req = kmem_zalloc(drctl_req_len, KM_SLEEP);
+	drctl_req->status = DRCTL_STATUS_INIT;
+
+	drctl_cmd = DRCTL_IO_CONFIG_REQUEST;
+
+	/*
+	 * Construct the path of the device as it will be if it
+	 * is successfully added.
+	 */
+	p = drctl_req->res_dev_path;
+	(void) sprintf(p, "/devices");
+	(void) ddi_pathname(pdip, p + strlen(p));
+	(void) sprintf(p + strlen(p), "/%s@%ld", name, devid);
+	DR_DBG_IO("%s: devpath=%s\n", __func__, drctl_req->res_dev_path);
+
+	if ((rv = drctl_config_init(drctl_cmd, drctl_flags, drctl_req,
+	    1, &drctl_res, &drctl_res_len, &drctl_res_ck)) != 0) {
+
+		DR_DBG_IO("%s: drctl_config_init failed: %d\n", __func__, rv);
+		goto done;
+
+	} else if (drctl_res->status == DRCTL_STATUS_DENY) {
+		res->result = DR_VIO_RES_BLOCKED;
+
+		DR_DBG_IO("%s: drctl_config_init denied\n", __func__);
+		p = (char *)drctl_res + drctl_res->offset;
+		reason_len = strlen(p);
+
+		if (reason_len >= DR_VIO_MAXREASONLEN)
+			reason_len = DR_VIO_MAXREASONLEN - 1;
+
+		(void) strncpy(res->reason, p, reason_len);
+		res->reason[reason_len] = '\0';
+		DR_DBG_IO("%s: %s\n", __func__, res->reason);
+
+		drctl_req->status = DRCTL_STATUS_CONFIG_FAILURE;
+
+		rv = EPERM;
+	} else {
+		cba.mdp = mdp;
+		cba.node = node;
+
+		br.arg = (void *)&cba;
+		br.type = DEVI_BRANCH_SID;
+		br.create.sid_branch_create = new_dev_node;
+		br.devi_branch_callback = NULL;
+
+		rv = e_ddi_branch_create(pdip,
+		    &br, NULL, DEVI_BRANCH_CONFIGURE);
+
+		drctl_req->status = (rv == 0) ?
+		    DRCTL_STATUS_CONFIG_SUCCESS : DRCTL_STATUS_CONFIG_FAILURE;
+
+		DR_DBG_IO("%s: %s@%ld = %d\n", __func__, name, devid, rv);
+	}
+
+	if (drctl_config_fini(&drctl_res_ck, drctl_req, 1) != 0)
+		DR_DBG_IO("%s: drctl_config_fini returned: %d\n", __func__, rv);
+
+done:
+	if (listp)
+		kmem_free(listp, listsz);
+
+	if (mdp)
+		(void) md_fini_handle(mdp);
+
+	if (pdip)
+		e_ddi_branch_rele(pdip);
+
+	kmem_free(drctl_req, drctl_req_len);
+	if (drctl_res)
+		kmem_free(drctl_res, drctl_res_len);
+
+	if (rv == 0) {
+		res->result = DR_VIO_RES_OK;
+		res->status = DR_VIO_STAT_CONFIGURED;
+
+		/* notify interested parties about the operation */
+		dr_generate_event(DR_TYPE_VIO, SE_HINT_INSERT);
+	} else {
+		res->status = DR_VIO_STAT_UNCONFIGURED;
+	}
+
+	return (rv);
+}
+
+static int
+dr_io_unconfigure(dr_vio_req_t *req, dr_vio_res_t *res)
+{
+	int		rv;
+	char		*name = req->name;
+	char		*p;
+	uint64_t	devid = req->dev_id;
+	dev_info_t	*dip;
+	dev_info_t	*fdip = NULL;
+	int		drctl_cmd;
+	int		drctl_flags = 0;
+	drctl_rsrc_t	*drctl_req;
+	size_t		drctl_req_len;
+	drctl_rsrc_t	*drctl_res = NULL;
+	size_t		drctl_res_len = 0;
+	drctl_cookie_t	drctl_res_ck;
+	size_t		reason_len;
+
+	if ((dip = dr_io_find_node(name, devid)) == NULL) {
+		DR_DBG_IO("%s: %s@%ld already unconfigured\n",
+		    __func__, name, devid);
+		res->result = DR_VIO_RES_OK;
+		res->status = DR_VIO_STAT_NOT_PRESENT;
+		return (0);
+	}
+
+	res->result = DR_VIO_RES_FAILURE;
+
+	ASSERT(e_ddi_branch_held(dip));
+
+	/* Assume we fail to unconfigure the resource. */
+	res->status = DR_VIO_STAT_CONFIGURED;
+
+	drctl_req_len = sizeof (drctl_rsrc_t) + MAXPATHLEN;
+	drctl_req = kmem_zalloc(drctl_req_len, KM_SLEEP);
+	drctl_req->status = DRCTL_STATUS_INIT;
+
+	drctl_cmd = DRCTL_IO_UNCONFIG_REQUEST;
+
+	if (req->msg_type == DR_VIO_FORCE_UNCONFIG)
+		drctl_flags = DRCTL_FLAG_FORCE;
+
+	p = drctl_req->res_dev_path;
+	(void) sprintf(p, "/devices");
+	(void) ddi_pathname(dip, p + strlen(p));
+	DR_DBG_IO("%s: devpath=%s\n", __func__, drctl_req->res_dev_path);
+
+	if ((rv = drctl_config_init(drctl_cmd, drctl_flags, drctl_req,
+	    1, &drctl_res, &drctl_res_len, &drctl_res_ck)) != 0) {
+
+		DR_DBG_IO("%s: drctl_config_init failed: %d\n", __func__, rv);
+		goto done;
+
+	} else if (drctl_res->status == DRCTL_STATUS_DENY) {
+		res->result = DR_VIO_RES_BLOCKED;
+
+		DR_DBG_IO("%s: drctl_config_init denied\n", __func__);
+		p = (char *)drctl_res + drctl_res->offset;
+		reason_len = strlen(p);
+
+		if (reason_len >= DR_VIO_MAXREASONLEN)
+			reason_len = DR_VIO_MAXREASONLEN - 1;
+
+		(void) strncpy(res->reason, p, reason_len);
+		res->reason[reason_len] = '\0';
+		DR_DBG_IO("%s: %s\n", __func__, res->reason);
+
+		drctl_req->status = DRCTL_STATUS_CONFIG_FAILURE;
+
+		rv = EPERM;
+	} else if (rv = e_ddi_branch_destroy(dip, &fdip, 0)) {
+		char *path = kmem_alloc(MAXPATHLEN, KM_SLEEP);
+
+		/*
+		 * If non-NULL, fdip is held and must be released.
+		 */
+		if (fdip != NULL) {
+			(void) ddi_pathname(fdip, path);
+			ddi_release_devi(fdip);
+		} else {
+			(void) ddi_pathname(dip, path);
+		}
+
+		DR_DBG_IO("%s: node removal failed: %s (%p)",
+		    __func__, path, (fdip) ? (void *)fdip : (void *)dip);
+
+		drctl_req->status = DRCTL_STATUS_CONFIG_FAILURE;
+
+		kmem_free(path, MAXPATHLEN);
+	} else {
+		drctl_req->status = DRCTL_STATUS_CONFIG_SUCCESS;
+	}
+
+	if (drctl_config_fini(&drctl_res_ck, drctl_req, 1) != 0)
+		DR_DBG_IO("%s: drctl_config_fini returned: %d\n", __func__, rv);
+
+	DR_DBG_IO("%s: (%s@%ld) = %d\n", __func__, name, devid, rv);
+
+	if (rv == 0) {
+		res->result = DR_VIO_RES_OK;
+		res->status = DR_VIO_STAT_UNCONFIGURED;
+
+		/* Notify interested parties about the operation. */
+		dr_generate_event(DR_TYPE_VIO, SE_HINT_REMOVE);
+	}
+done:
+	kmem_free(drctl_req, drctl_req_len);
+
+	if (drctl_res)
+		kmem_free(drctl_res, drctl_res_len);
+
+	return (rv);
+}
+
+static void
+dr_vio_data_handler(ds_cb_arg_t arg, void *buf, size_t buflen)
+{
+	_NOTE(ARGUNUSED(arg))
+
+	size_t		res_len;
+	dr_vio_res_t	*res;
+	dr_vio_req_t	*req;
+
+	/*
+	 * Allocate a response buffer, because we always want to
+	 * send back a response message.
+	 */
+	res_len = sizeof (dr_vio_res_t) + DR_VIO_MAXREASONLEN;
+	res = kmem_zalloc(res_len, KM_SLEEP);
+	res->result = DR_VIO_RES_FAILURE;
+
+	/*
+	 * Sanity check the message
+	 */
+	if (buf == NULL) {
+		DR_DBG_IO("empty message: expected at least %ld bytes\n",
+		    sizeof (dr_vio_req_t));
+		goto done;
+	}
+	if (buflen < sizeof (dr_vio_req_t)) {
+		DR_DBG_IO("incoming message short: expected at least %ld "
+		    "bytes, received %ld\n", sizeof (dr_vio_req_t), buflen);
+		goto done;
+	}
+
+	DR_DBG_TRANS("incoming request:\n");
+	DR_DBG_DUMP_MSG(buf, buflen);
+
+	req = buf;
+	switch (req->msg_type) {
+	case DR_VIO_CONFIGURE:
+		(void) dr_io_configure(req, res);
+		break;
+	case DR_VIO_FORCE_UNCONFIG:
+	case DR_VIO_UNCONFIGURE:
+		(void) dr_io_unconfigure(req, res);
+		break;
+	default:
+		cmn_err(CE_NOTE, "bad msg_type %d\n", req->msg_type);
+		break;
+	}
+done:
+	res->req_num = (req) ? req->req_num : 0;
+
+	DR_DBG_TRANS("outgoing response:\n");
+	DR_DBG_DUMP_MSG(res, res_len);
+
+	/* send back the response */
+	if (ds_cap_send(ds_vio_handle, res, res_len) != 0)
+		DR_DBG_IO("ds_send failed\n");
+
+	if (res)
+		kmem_free(res, res_len);
+}
+
+static void
+dr_vio_reg_handler(ds_cb_arg_t arg, ds_ver_t *ver, ds_svc_hdl_t hdl)
+{
+	DR_DBG_IO("vio_reg_handler: arg=0x%p, ver=%d.%d, hdl=0x%lx\n",
+	    arg, ver->major, ver->minor, hdl);
+
+	ds_vio_handle = hdl;
+}
+
+static void
+dr_vio_unreg_handler(ds_cb_arg_t arg)
+{
+	DR_DBG_IO("vio_unreg_handler: arg=0x%p\n", arg);
+
+	ds_vio_handle = DS_INVALID_HDL;
+}
+
+static int
+dr_io_init(void)
+{
+	int	rv;
+
+	if ((rv = ds_cap_init(&dr_vio_cap, &dr_vio_ops)) != 0) {
+		cmn_err(CE_NOTE, "ds_cap_init vio failed: %d", rv);
+		return (-1);
+	}
+
+	return (0);
+}
+
+static int
+dr_io_fini(void)
+{
+	int	rv;
+
+	if ((rv = ds_cap_fini(&dr_vio_cap)) != 0) {
+		cmn_err(CE_NOTE, "ds_cap_fini vio failed: %d", rv);
+		return (-1);
+	}
+
+	return (0);
+}
+
+int
+_init(void)
+{
+	int	status;
+
+	/* check that IO DR is enabled */
+	if (dr_is_disabled(DR_TYPE_VIO)) {
+		cmn_err(CE_CONT, "!VIO DR is disabled\n");
+		return (-1);
+	}
+
+	if ((status = dr_io_init()) != 0) {
+		cmn_err(CE_NOTE, "VIO DR initialization failed");
+		return (status);
+	}
+
+	if ((status = mod_install(&modlinkage)) != 0) {
+		(void) dr_io_fini();
+	}
+
+	return (status);
+}
+
+int
+_info(struct modinfo *modinfop)
+{
+	return (mod_info(&modlinkage, modinfop));
+}
+
+int dr_io_allow_unload = 0;
+
+int
+_fini(void)
+{
+	int	status;
+
+	if (dr_io_allow_unload == 0)
+		return (EBUSY);
+
+	if ((status = mod_remove(&modlinkage)) == 0) {
+		(void) dr_io_fini();
+	}
+
+	return (status);
+}
diff --git a/usr/src/uts/sun4v/io/drctl.c b/usr/src/uts/sun4v/io/drctl.c
index 1383c2d41f..1a49beba03 100644
--- a/usr/src/uts/sun4v/io/drctl.c
+++ b/usr/src/uts/sun4v/io/drctl.c
@@ -20,7 +20,7 @@
  */
 
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -314,16 +314,16 @@ drctl_config_common(int cmd, int flags, drctl_rsrc_t *res,
 	case DRCTL_CPU_CONFIG_NOTIFY:
 	case DRCTL_CPU_UNCONFIG_REQUEST:
 	case DRCTL_CPU_UNCONFIG_NOTIFY:
+	case DRCTL_IO_UNCONFIG_REQUEST:
+	case DRCTL_IO_UNCONFIG_NOTIFY:
+	case DRCTL_IO_CONFIG_REQUEST:
+	case DRCTL_IO_CONFIG_NOTIFY:
 		rv = 0;
 		break;
 	case DRCTL_MEM_CONFIG_REQUEST:
 	case DRCTL_MEM_CONFIG_NOTIFY:
 	case DRCTL_MEM_UNCONFIG_REQUEST:
 	case DRCTL_MEM_UNCONFIG_NOTIFY:
-	case DRCTL_IO_CONFIG_REQUEST:
-	case DRCTL_IO_CONFIG_NOTIFY:
-	case DRCTL_IO_UNCONFIG_REQUEST:
-	case DRCTL_IO_UNCONFIG_NOTIFY:
 		rv = ENOTSUP;
 		break;
 	}
@@ -498,14 +498,18 @@ drctl_config_fini(drctl_cookie_t ck, drctl_rsrc_t *res, int count)
 		notify_cmd = DRCTL_CPU_UNCONFIG_NOTIFY;
 		break;
 
+	case DRCTL_IO_UNCONFIG_REQUEST:
+		notify_cmd = DRCTL_IO_UNCONFIG_NOTIFY;
+		break;
+
+	case DRCTL_IO_CONFIG_REQUEST:
+		notify_cmd = DRCTL_IO_CONFIG_NOTIFY;
+		break;
+
 	case DRCTL_MEM_CONFIG_REQUEST:
 	case DRCTL_MEM_CONFIG_NOTIFY:
 	case DRCTL_MEM_UNCONFIG_REQUEST:
 	case DRCTL_MEM_UNCONFIG_NOTIFY:
-	case DRCTL_IO_CONFIG_REQUEST:
-	case DRCTL_IO_CONFIG_NOTIFY:
-	case DRCTL_IO_UNCONFIG_REQUEST:
-	case DRCTL_IO_UNCONFIG_NOTIFY:
 	default:
 		/* none of the above should have been accepted in _init */
 		ASSERT(0);
@@ -566,27 +570,37 @@ send_message(void *msg, size_t size, void **obufp, size_t *osize)
 static void *
 pack_message(int cmd, int flags, int count, void *data, size_t *osize)
 {
-	drd_msg_t *msgp;
+	drd_msg_t *msgp = NULL;
 	size_t hdr_size = offsetof(drd_msg_t, data);
+	size_t data_size = 0;
 
 	switch (cmd) {
 	case DRCTL_CPU_CONFIG_REQUEST:
 	case DRCTL_CPU_CONFIG_NOTIFY:
 	case DRCTL_CPU_UNCONFIG_REQUEST:
 	case DRCTL_CPU_UNCONFIG_NOTIFY:
+		data_size = count * sizeof (drctl_rsrc_t);
+		break;
+	case DRCTL_IO_CONFIG_REQUEST:
+	case DRCTL_IO_CONFIG_NOTIFY:
+	case DRCTL_IO_UNCONFIG_REQUEST:
+	case DRCTL_IO_UNCONFIG_NOTIFY:
+		data_size = sizeof (drctl_rsrc_t) +
+		    strlen(((drctl_rsrc_t *)data)->res_dev_path);
+		break;
+	default:
+		cmn_err(CE_WARN,
+		    "drctl: pack_message received invalid cmd %d", cmd);
+		break;
+	}
 
-		*osize = hdr_size + count * sizeof (drctl_rsrc_t);
-
+	if (data_size) {
+		*osize = hdr_size + data_size;
 		msgp = kmem_alloc(*osize, KM_SLEEP);
 		msgp->cmd = cmd;
 		msgp->count = count;
 		msgp->flags = flags;
-		bcopy(data, msgp->data, count * sizeof (drctl_rsrc_t));
-		break;
-	default:
-		cmn_err(CE_WARN,
-		    "drctl: pack_message received invalid cmd %d", cmd);
-		msgp = NULL;
+		bcopy(data, msgp->data, data_size);
 	}
 
 	return (msgp);
diff --git a/usr/src/uts/sun4v/os/mach_startup.c b/usr/src/uts/sun4v/os/mach_startup.c
index 8159aa8967..6c521d5374 100644
--- a/usr/src/uts/sun4v/os/mach_startup.c
+++ b/usr/src/uts/sun4v/os/mach_startup.c
@@ -498,6 +498,9 @@ load_mach_drivers(void)
 	if (domaining_enabled() && modload("misc", "dr_cpu") == -1)
 		cmn_err(CE_NOTE, "!'dr_cpu' module failed to load");
 
+	if (modload("misc", "dr_io") == -1)
+		cmn_err(CE_NOTE, "!'dr_io' module failed to load");
+
 	/*
 	 * Attempt to attach any virtual device servers. These
 	 * drivers must be loaded at start of day so that they
diff --git a/usr/src/uts/sun4v/sys/dr_io.h b/usr/src/uts/sun4v/sys/dr_io.h
new file mode 100644
index 0000000000..a189aa0248
--- /dev/null
+++ b/usr/src/uts/sun4v/sys/dr_io.h
@@ -0,0 +1,90 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#ifndef _DR_IO_H
+#define	_DR_IO_H
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+/*
+ * VIO DR Control Protocol
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Values of 'msg_type' element of the request message
+ */
+#define	DR_VIO_CONFIGURE	0x494f43	/* 'IOC' */
+#define	DR_VIO_UNCONFIGURE	0x494f55	/* 'IOU' */
+#define	DR_VIO_FORCE_UNCONFIG	0x494f46	/* 'IOF' */
+#define	DR_VIO_STATUS		0x494f53	/* 'IOS' */
+
+/*
+ * VIO DR Request
+ */
+typedef struct {
+	uint64_t	req_num;
+	uint64_t	dev_id;
+	uint32_t	msg_type;
+	char		name[1];
+} dr_vio_req_t;
+
+/*
+ * Values of 'result' element of the response message
+ */
+#define	DR_VIO_RES_OK			0x0
+#define	DR_VIO_RES_FAILURE		0x1
+#define	DR_VIO_RES_BLOCKED		0x2
+#define	DR_VIO_RES_NOT_IN_MD		0x3
+
+/*
+ * Values of 'status' element of the response message
+ */
+#define	DR_VIO_STAT_NOT_PRESENT		0x0
+#define	DR_VIO_STAT_UNCONFIGURED	0x1
+#define	DR_VIO_STAT_CONFIGURED		0x2
+
+/*
+ * VIO DR Response
+ */
+typedef struct {
+	uint64_t	req_num;
+	uint32_t	result;
+	uint32_t	status;
+	char		reason[1];
+} dr_vio_res_t;
+
+#define	DR_VIO_DS_ID		"dr-vio"
+#define	DR_VIO_MAXREASONLEN	1024
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _DR_IO_H */
diff --git a/usr/src/uts/sun4v/sys/dr_util.h b/usr/src/uts/sun4v/sys/dr_util.h
index 944738ff29..7f99cf0461 100644
--- a/usr/src/uts/sun4v/sys/dr_util.h
+++ b/usr/src/uts/sun4v/sys/dr_util.h
@@ -20,7 +20,7 @@
  */
 
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -82,8 +82,7 @@ typedef enum {
 	DR_TYPE_INVAL,
 	DR_TYPE_CPU,
 	DR_TYPE_MEM,
-	DR_TYPE_VIO,
-	DR_TYPE_DIO
+	DR_TYPE_VIO
 } dr_type_t;
 
 /*
@@ -95,7 +94,6 @@ typedef enum {
 			    (t) == DR_TYPE_CPU ? OBP_CPU : 	\
 			    (t) == DR_TYPE_MEM ? "memory" :	\
 			    (t) == DR_TYPE_VIO ? "vio" :	\
-			    (t) == DR_TYPE_DIO ? "dio" :	\
 			    "unknown")
 
 extern boolean_t dr_is_disabled(dr_type_t type);