MFC r305898, r309120, r309121 (by jceel):

Add virtio-console support to bhyve.

Adds virtio-console device support to bhyve, allowing to create
bidirectional character streams between host and guest.

Syntax:
-s <slotnum>,virtio-console,port1=/path/to/port1.sock,anotherport=...

Maximum of 16 ports per device can be created. Every port is named
and corresponds to an Unix domain socket created by bhyve. bhyve
accepts at most one connection per port at a time.

Limitations:
- due to lack of destructors of in bhyve, sockets on the filesystem
  must be cleaned up manually after bhyve exits
- there's no way to use "console port" feature, nor the console port
  resize as of now
- emergency write is advertised, but no-op as of now

3 files changed, 651 insertions, 0 deletions

diff --git a/usr.sbin/bhyve/Makefile b/usr.sbin/bhyve/Makefile
index 892fae6..8159d7d 100644
--- a/usr.sbin/bhyve/Makefile
+++ b/usr.sbin/bhyve/Makefile
@@ -38,6 +38,7 @@ SRCS=	\
 	pci_lpc.c		\
 	pci_passthru.c		\
 	pci_virtio_block.c	\
+	pci_virtio_console.c	\
 	pci_virtio_net.c	\
 	pci_virtio_rnd.c	\
 	pci_uart.c		\
diff --git a/usr.sbin/bhyve/pci_virtio_console.c b/usr.sbin/bhyve/pci_virtio_console.c
new file mode 100644
index 0000000..9cba5f7
--- /dev/null
+++ b/usr.sbin/bhyve/pci_virtio_console.c
@@ -0,0 +1,649 @@
+/*-
+ * Copyright (c) 2016 iXsystems Inc.
+ * All rights reserved.
+ *
+ * This software was developed by Jakub Klama <jceel@FreeBSD.org>
+ * under sponsorship from iXsystems Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer
+ *    in this position and unchanged.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/linker_set.h>
+#include <sys/uio.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <assert.h>
+#include <pthread.h>
+#include <libgen.h>
+
+#include "bhyverun.h"
+#include "pci_emul.h"
+#include "virtio.h"
+#include "mevent.h"
+#include "sockstream.h"
+
+#define	VTCON_RINGSZ	64
+#define	VTCON_MAXPORTS	16
+#define	VTCON_MAXQ	(VTCON_MAXPORTS * 2 + 2)
+
+#define	VTCON_DEVICE_READY	0
+#define	VTCON_DEVICE_ADD	1
+#define	VTCON_DEVICE_REMOVE	2
+#define	VTCON_PORT_READY	3
+#define	VTCON_CONSOLE_PORT	4
+#define	VTCON_CONSOLE_RESIZE	5
+#define	VTCON_PORT_OPEN		6
+#define	VTCON_PORT_NAME		7
+
+#define	VTCON_F_SIZE		0
+#define	VTCON_F_MULTIPORT	1
+#define	VTCON_F_EMERG_WRITE	2
+#define	VTCON_S_HOSTCAPS	\
+    (VTCON_F_SIZE | VTCON_F_MULTIPORT | VTCON_F_EMERG_WRITE)
+
+static int pci_vtcon_debug;
+#define DPRINTF(params) if (pci_vtcon_debug) printf params
+#define WPRINTF(params) printf params
+
+struct pci_vtcon_softc;
+struct pci_vtcon_port;
+struct pci_vtcon_config;
+typedef void (pci_vtcon_cb_t)(struct pci_vtcon_port *, void *, struct iovec *,
+    int);
+
+struct pci_vtcon_port {
+	struct pci_vtcon_softc * vsp_sc;
+	int                      vsp_id;
+	const char *             vsp_name;
+	bool                     vsp_enabled;
+	bool                     vsp_console;
+	bool                     vsp_rx_ready;
+	bool                     vsp_open;
+	int                      vsp_rxq;
+	int                      vsp_txq;
+	void *                   vsp_arg;
+	pci_vtcon_cb_t *         vsp_cb;
+};
+
+struct pci_vtcon_sock
+{
+	struct pci_vtcon_port *  vss_port;
+	const char *             vss_path;
+	struct mevent *          vss_server_evp;
+	struct mevent *          vss_conn_evp;
+	int                      vss_server_fd;
+	int                      vss_conn_fd;
+	bool                     vss_open;
+};
+
+struct pci_vtcon_softc {
+	struct virtio_softc      vsc_vs;
+	struct vqueue_info       vsc_queues[VTCON_MAXQ];
+	pthread_mutex_t          vsc_mtx;
+	uint64_t                 vsc_cfg;
+	uint64_t                 vsc_features;
+	char *                   vsc_rootdir;
+	int                      vsc_kq;
+	int                      vsc_nports;
+	bool                     vsc_ready;
+	struct pci_vtcon_port    vsc_control_port;
+ 	struct pci_vtcon_port    vsc_ports[VTCON_MAXPORTS];
+	struct pci_vtcon_config *vsc_config;
+};
+
+struct pci_vtcon_config {
+	uint16_t cols;
+	uint16_t rows;
+	uint32_t max_nr_ports;
+	uint32_t emerg_wr;
+} __attribute__((packed));
+
+struct pci_vtcon_control {
+	uint32_t id;
+	uint16_t event;
+	uint16_t value;
+} __attribute__((packed));
+
+struct pci_vtcon_console_resize {
+	uint16_t cols;
+	uint16_t rows;
+} __attribute__((packed));
+
+static void pci_vtcon_reset(void *);
+static void pci_vtcon_notify_rx(void *, struct vqueue_info *);
+static void pci_vtcon_notify_tx(void *, struct vqueue_info *);
+static int pci_vtcon_cfgread(void *, int, int, uint32_t *);
+static int pci_vtcon_cfgwrite(void *, int, int, uint32_t);
+static void pci_vtcon_neg_features(void *, uint64_t);
+static void pci_vtcon_sock_accept(int, enum ev_type,  void *);
+static void pci_vtcon_sock_rx(int, enum ev_type, void *);
+static void pci_vtcon_sock_tx(struct pci_vtcon_port *, void *, struct iovec *,
+    int);
+static void pci_vtcon_control_send(struct pci_vtcon_softc *,
+    struct pci_vtcon_control *, const void *, size_t);
+static void pci_vtcon_announce_port(struct pci_vtcon_port *);
+static void pci_vtcon_open_port(struct pci_vtcon_port *, bool);
+
+static struct virtio_consts vtcon_vi_consts = {
+	"vtcon",		/* our name */
+	VTCON_MAXQ,		/* we support VTCON_MAXQ virtqueues */
+	sizeof(struct pci_vtcon_config), /* config reg size */
+	pci_vtcon_reset,	/* reset */
+	NULL,			/* device-wide qnotify */
+	pci_vtcon_cfgread,	/* read virtio config */
+	pci_vtcon_cfgwrite,	/* write virtio config */
+	pci_vtcon_neg_features,	/* apply negotiated features */
+	VTCON_S_HOSTCAPS,	/* our capabilities */
+};
+
+
+static void
+pci_vtcon_reset(void *vsc)
+{
+	struct pci_vtcon_softc *sc;
+
+	sc = vsc;
+
+	DPRINTF(("vtcon: device reset requested!\n"));
+	vi_reset_dev(&sc->vsc_vs);
+}
+
+static void
+pci_vtcon_neg_features(void *vsc, uint64_t negotiated_features)
+{
+	struct pci_vtcon_softc *sc = vsc;
+
+	sc->vsc_features = negotiated_features;
+}
+
+static int
+pci_vtcon_cfgread(void *vsc, int offset, int size, uint32_t *retval)
+{
+	struct pci_vtcon_softc *sc = vsc;
+	void *ptr;
+
+	ptr = (uint8_t *)sc->vsc_config + offset;
+	memcpy(retval, ptr, size);
+	return (0);
+}
+
+static int
+pci_vtcon_cfgwrite(void *vsc, int offset, int size, uint32_t val)
+{
+
+	return (0);
+}
+
+static inline struct pci_vtcon_port *
+pci_vtcon_vq_to_port(struct pci_vtcon_softc *sc, struct vqueue_info *vq)
+{
+	uint16_t num = vq->vq_num;
+
+	if (num == 0 || num == 1)
+		return (&sc->vsc_ports[0]);
+
+	if (num == 2 || num == 3)
+		return (&sc->vsc_control_port);
+
+	return (&sc->vsc_ports[(num / 2) - 1]);
+}
+
+static inline struct vqueue_info *
+pci_vtcon_port_to_vq(struct pci_vtcon_port *port, bool tx_queue)
+{
+	int qnum;
+
+	qnum = tx_queue ? port->vsp_txq : port->vsp_rxq;
+	return (&port->vsp_sc->vsc_queues[qnum]);
+}
+
+static struct pci_vtcon_port *
+pci_vtcon_port_add(struct pci_vtcon_softc *sc, const char *name,
+    pci_vtcon_cb_t *cb, void *arg)
+{
+	struct pci_vtcon_port *port;
+
+	if (sc->vsc_nports == VTCON_MAXPORTS) {
+		errno = EBUSY;
+		return (NULL);
+	}
+
+	port = &sc->vsc_ports[sc->vsc_nports++];
+	port->vsp_id = sc->vsc_nports - 1;
+	port->vsp_sc = sc;
+	port->vsp_name = name;
+	port->vsp_cb = cb;
+	port->vsp_arg = arg;
+
+	if (port->vsp_id == 0) {
+		/* port0 */
+		port->vsp_txq = 0;
+		port->vsp_rxq = 1;
+	} else {
+		port->vsp_txq = sc->vsc_nports * 2;
+		port->vsp_rxq = port->vsp_txq + 1;
+	}
+
+	port->vsp_enabled = true;
+	return (port);
+}
+
+static int
+pci_vtcon_sock_add(struct pci_vtcon_softc *sc, const char *name,
+    const char *path)
+{
+	struct pci_vtcon_sock *sock;
+	struct sockaddr_un sun;
+	int s = -1, fd = -1, error = 0;
+
+	sock = calloc(1, sizeof(struct pci_vtcon_sock));
+	if (sock == NULL) {
+		error = -1;
+		goto out;
+	}
+
+	s = socket(AF_UNIX, SOCK_STREAM, 0);
+	if (s < 0) {
+		error = -1;
+		goto out;
+	}
+
+	fd = open(dirname(path), O_RDONLY | O_DIRECTORY);
+	if (fd < 0) {
+		error = -1;
+		goto out;
+	}
+
+	sun.sun_family = AF_UNIX;
+	sun.sun_len = sizeof(struct sockaddr_un);
+	strncpy(sun.sun_path, basename((char *)path), sizeof(sun.sun_path));
+
+	if (bindat(fd, s, (struct sockaddr *)&sun, sun.sun_len) < 0) {
+		error = -1;
+		goto out;
+	}
+
+	if (fcntl(s, F_SETFL, O_NONBLOCK) < 0) {
+		error = -1;
+		goto out;
+	}
+
+	if (listen(s, 1) < 0) {
+		error = -1;
+		goto out;
+	}
+
+
+	sock->vss_port = pci_vtcon_port_add(sc, name, pci_vtcon_sock_tx, sock);
+	if (sock->vss_port == NULL) {
+		error = -1;
+		goto out;
+	}
+
+	sock->vss_open = false;
+	sock->vss_conn_fd = -1;
+	sock->vss_server_fd = s;
+	sock->vss_server_evp = mevent_add(s, EVF_READ, pci_vtcon_sock_accept,
+	    sock);
+
+	if (sock->vss_server_evp == NULL) {
+		error = -1;
+		goto out;
+	}
+
+out:
+	if (fd != -1)
+		close(fd);
+
+	if (error != 0 && s != -1)
+		close(s);
+
+	return (error);
+}
+
+static void
+pci_vtcon_sock_accept(int fd __unused, enum ev_type t __unused, void *arg)
+{
+	struct pci_vtcon_sock *sock = (struct pci_vtcon_sock *)arg;
+	int s;
+
+	s = accept(sock->vss_server_fd, NULL, NULL);
+	if (s < 0)
+		return;
+
+	if (sock->vss_open) {
+		close(s);
+		return;
+	}
+
+	sock->vss_open = true;
+	sock->vss_conn_fd = s;
+	sock->vss_conn_evp = mevent_add(s, EVF_READ, pci_vtcon_sock_rx, sock);
+
+	pci_vtcon_open_port(sock->vss_port, true);
+}
+
+static void
+pci_vtcon_sock_rx(int fd __unused, enum ev_type t __unused, void *arg)
+{
+	struct pci_vtcon_port *port;
+	struct pci_vtcon_sock *sock = (struct pci_vtcon_sock *)arg;
+	struct vqueue_info *vq;
+	struct iovec iov;
+	static char dummybuf[2048];
+	int len, n;
+	uint16_t idx;
+
+	port = sock->vss_port;
+	vq = pci_vtcon_port_to_vq(port, true);
+
+	if (!sock->vss_open || !port->vsp_rx_ready) {
+		len = read(sock->vss_conn_fd, dummybuf, sizeof(dummybuf));
+		if (len == 0)
+			goto close;
+
+		return;
+	}
+
+	if (!vq_has_descs(vq)) {
+		len = read(sock->vss_conn_fd, dummybuf, sizeof(dummybuf));
+		vq_endchains(vq, 1);
+		if (len == 0)
+			goto close;
+
+		return;
+	}
+
+	do {
+		n = vq_getchain(vq, &idx, &iov, 1, NULL);
+		len = readv(sock->vss_conn_fd, &iov, n);
+
+		if (len == 0 || (len < 0 && errno == EWOULDBLOCK)) {
+			vq_retchain(vq);
+			vq_endchains(vq, 0);
+			if (len == 0)
+				goto close;
+
+			return;
+		}
+
+		vq_relchain(vq, idx, len);
+	} while (vq_has_descs(vq));
+
+	vq_endchains(vq, 1);
+
+close:
+	mevent_delete_close(sock->vss_conn_evp);
+	sock->vss_conn_fd = -1;
+	sock->vss_open = false;
+}
+
+static void
+pci_vtcon_sock_tx(struct pci_vtcon_port *port, void *arg, struct iovec *iov,
+    int niov)
+{
+	struct pci_vtcon_sock *sock;
+	int i, ret;
+
+	sock = (struct pci_vtcon_sock *)arg;
+
+	if (sock->vss_conn_fd == -1)
+		return;
+
+	for (i = 0; i < niov; i++) {
+		ret = stream_write(sock->vss_conn_fd, iov[i].iov_base,
+		    iov[i].iov_len);
+		if (ret <= 0)
+			break;
+	}
+
+	if (ret <= 0) {
+		mevent_delete_close(sock->vss_conn_evp);
+		sock->vss_conn_fd = -1;
+		sock->vss_open = false;
+	}
+}
+
+static void
+pci_vtcon_control_tx(struct pci_vtcon_port *port, void *arg, struct iovec *iov,
+    int niov)
+{
+	struct pci_vtcon_softc *sc;
+	struct pci_vtcon_port *tmp;
+	struct pci_vtcon_control resp, *ctrl;
+	int i;
+
+	assert(niov == 1);
+
+	sc = port->vsp_sc;
+	ctrl = (struct pci_vtcon_control *)iov->iov_base;
+
+	switch (ctrl->event) {
+	case VTCON_DEVICE_READY:
+		sc->vsc_ready = true;
+		/* set port ready events for registered ports */
+		for (i = 0; i < VTCON_MAXPORTS; i++) {
+			tmp = &sc->vsc_ports[i];
+			if (tmp->vsp_enabled)
+				pci_vtcon_announce_port(tmp);
+
+			if (tmp->vsp_open)
+				pci_vtcon_open_port(tmp, true);
+		}
+		break;
+
+	case VTCON_PORT_READY:
+		if (ctrl->id >= sc->vsc_nports) {
+			WPRINTF(("VTCON_PORT_READY event for unknown port %d\n",
+			    ctrl->id));
+			return;
+		}
+
+		tmp = &sc->vsc_ports[ctrl->id];
+		if (tmp->vsp_console) {
+			resp.event = VTCON_CONSOLE_PORT;
+			resp.id = ctrl->id;
+			resp.value = 1;
+			pci_vtcon_control_send(sc, &resp, NULL, 0);
+		}
+		break;
+	}
+}
+
+static void
+pci_vtcon_announce_port(struct pci_vtcon_port *port)
+{
+	struct pci_vtcon_control event;
+
+	event.id = port->vsp_id;
+	event.event = VTCON_DEVICE_ADD;
+	event.value = 1;
+	pci_vtcon_control_send(port->vsp_sc, &event, NULL, 0);
+
+	event.event = VTCON_PORT_NAME;
+	pci_vtcon_control_send(port->vsp_sc, &event, port->vsp_name,
+	    strlen(port->vsp_name));
+}
+
+static void
+pci_vtcon_open_port(struct pci_vtcon_port *port, bool open)
+{
+	struct pci_vtcon_control event;
+
+	if (!port->vsp_sc->vsc_ready) {
+		port->vsp_open = true;
+		return;
+	}
+
+	event.id = port->vsp_id;
+	event.event = VTCON_PORT_OPEN;
+	event.value = (int)open;
+	pci_vtcon_control_send(port->vsp_sc, &event, NULL, 0);
+}
+
+static void
+pci_vtcon_control_send(struct pci_vtcon_softc *sc,
+    struct pci_vtcon_control *ctrl, const void *payload, size_t len)
+{
+	struct vqueue_info *vq;
+	struct iovec iov;
+	uint16_t idx;
+	int n;
+
+	vq = pci_vtcon_port_to_vq(&sc->vsc_control_port, true);
+
+	if (!vq_has_descs(vq))
+		return;
+
+	n = vq_getchain(vq, &idx, &iov, 1, NULL);
+
+	assert(n == 1);
+
+	memcpy(iov.iov_base, ctrl, sizeof(struct pci_vtcon_control));
+	if (payload != NULL && len > 0)
+		memcpy(iov.iov_base + sizeof(struct pci_vtcon_control),
+		     payload, len);
+
+	vq_relchain(vq, idx, sizeof(struct pci_vtcon_control) + len);
+	vq_endchains(vq, 1);
+}
+    
+
+static void
+pci_vtcon_notify_tx(void *vsc, struct vqueue_info *vq)
+{
+	struct pci_vtcon_softc *sc;
+	struct pci_vtcon_port *port;
+	struct iovec iov[1];
+	uint16_t idx, n;
+	uint16_t flags[8];
+
+	sc = vsc;
+	port = pci_vtcon_vq_to_port(sc, vq);
+
+	while (vq_has_descs(vq)) {
+		n = vq_getchain(vq, &idx, iov, 1, flags);
+		if (port != NULL)
+			port->vsp_cb(port, port->vsp_arg, iov, 1);
+
+		/*
+		 * Release this chain and handle more
+		 */
+		vq_relchain(vq, idx, 0);
+	}
+	vq_endchains(vq, 1);	/* Generate interrupt if appropriate. */
+}
+
+static void
+pci_vtcon_notify_rx(void *vsc, struct vqueue_info *vq)
+{
+	struct pci_vtcon_softc *sc;
+	struct pci_vtcon_port *port;
+
+	sc = vsc;
+	port = pci_vtcon_vq_to_port(sc, vq);
+
+	if (!port->vsp_rx_ready) {
+		port->vsp_rx_ready = 1;
+		vq->vq_used->vu_flags |= VRING_USED_F_NO_NOTIFY;
+	}
+}
+
+static int
+pci_vtcon_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts)
+{
+	struct pci_vtcon_softc *sc;
+	char *portname = NULL;
+	char *portpath = NULL;
+	char *opt;
+	int i;	
+
+	sc = calloc(1, sizeof(struct pci_vtcon_softc));
+	sc->vsc_config = calloc(1, sizeof(struct pci_vtcon_config));
+	sc->vsc_config->max_nr_ports = VTCON_MAXPORTS;
+	sc->vsc_config->cols = 80;
+	sc->vsc_config->rows = 25; 
+
+	vi_softc_linkup(&sc->vsc_vs, &vtcon_vi_consts, sc, pi, sc->vsc_queues);
+	sc->vsc_vs.vs_mtx = &sc->vsc_mtx;
+
+	for (i = 0; i < VTCON_MAXQ; i++) {
+		sc->vsc_queues[i].vq_qsize = VTCON_RINGSZ;
+		sc->vsc_queues[i].vq_notify = i % 2 == 0
+		    ? pci_vtcon_notify_rx
+		    : pci_vtcon_notify_tx;
+	}
+
+	/* initialize config space */
+	pci_set_cfgdata16(pi, PCIR_DEVICE, VIRTIO_DEV_CONSOLE);
+	pci_set_cfgdata16(pi, PCIR_VENDOR, VIRTIO_VENDOR);
+	pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_SIMPLECOMM);
+	pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_TYPE_CONSOLE);
+	pci_set_cfgdata16(pi, PCIR_SUBVEND_0, VIRTIO_VENDOR);
+
+	if (vi_intr_init(&sc->vsc_vs, 1, fbsdrun_virtio_msix()))
+		return (1);
+	vi_set_io_bar(&sc->vsc_vs, 0);
+
+	/* create control port */
+	sc->vsc_control_port.vsp_sc = sc;
+	sc->vsc_control_port.vsp_txq = 2;
+	sc->vsc_control_port.vsp_rxq = 3;
+	sc->vsc_control_port.vsp_cb = pci_vtcon_control_tx;
+	sc->vsc_control_port.vsp_enabled = true;
+
+	while ((opt = strsep(&opts, ",")) != NULL) {
+		portname = strsep(&opt, "=");
+		portpath = strdup(opt);
+
+		/* create port */
+		if (pci_vtcon_sock_add(sc, portname, portpath) < 0) {
+			fprintf(stderr, "cannot create port %s: %s\n",
+			    portname, strerror(errno));
+			return (1);
+		}
+	}
+
+	return (0);
+}
+
+struct pci_devemu pci_de_vcon = {
+	.pe_emu =	"virtio-console",
+	.pe_init =	pci_vtcon_init,
+	.pe_barwrite =	vi_pci_write,
+	.pe_barread =	vi_pci_read
+};
+PCI_EMUL_SET(pci_de_vcon);
diff --git a/usr.sbin/bhyve/virtio.h b/usr.sbin/bhyve/virtio.h
index 28eecc7..ce40c7d 100644
--- a/usr.sbin/bhyve/virtio.h
+++ b/usr.sbin/bhyve/virtio.h
@@ -210,6 +210,7 @@ struct vring_used {
 #define	VIRTIO_DEV_NET		0x1000
 #define	VIRTIO_DEV_BLOCK	0x1001
 #define	VIRTIO_DEV_RANDOM	0x1005
+#define	VIRTIO_DEV_CONSOLE	0x1003
 
 /*
  * PCI config space constants.