add virtio-console driver

This patch adds a new driver for use of virtio-console devices as
ttys.  It's still in an early state and not compiled by default, yet.
Currently it is only wired into amd64. i386 is still missing.

Discussed with uebayasi@, deraadt@

8 files changed, 694 insertions, 7 deletions

diff --git a/etc/MAKEDEV.common b/etc/MAKEDEV.common
index 1f03b7636c0..92cce531a1a 100644
--- a/etc/MAKEDEV.common
+++ b/etc/MAKEDEV.common
@@ -1,4 +1,4 @@
-vers(a, {-$OpenBSD: MAKEDEV.common,v 1.82 2015/12/09 04:11:58 deraadt Exp $-})dnl
+vers(a, {-$OpenBSD: MAKEDEV.common,v 1.83 2015/12/21 22:15:53 sf Exp $-})dnl
 dnl
 dnl Copyright (c) 2001-2006 Todd T. Fries <todd@OpenBSD.org>
 dnl
@@ -383,6 +383,8 @@ _mkdev(com, {-tty[0-7][0-9a-f]-}, {-U=${i#tty*}
 	M tty$U c major_com_c $o 660 dialer uucp
 	M cua$U c major_com_c Add($o, 128) 660 dialer uucp-})dnl
 __devitem(ttyc, ttyc*, Cyclades serial ports,cy)dnl
+__devitem(ttyVI, ttyVI*, Virtio serial ports,viocon)dnl
+_mkdev(ttyVI, ttyVI*, {-M ttyVI$U c major_ttyVI_c $U 660 dialer uucp-})dnl
 __devitem(tzs, tty[a-z]*, Zilog 8530 Serial Port,zs)dnl
 _mkdev(tzs, {-tty[a-z]-}, {-u=${i#tty*}
 	case $u in
diff --git a/etc/etc.amd64/MAKEDEV.md b/etc/etc.amd64/MAKEDEV.md
index 390867ce853..104a91bc449 100644
--- a/etc/etc.amd64/MAKEDEV.md
+++ b/etc/etc.amd64/MAKEDEV.md
@@ -1,6 +1,6 @@
 define(MACHINE,amd64)dnl
 vers(__file__,
-	{-$OpenBSD: MAKEDEV.md,v 1.61 2015/11/10 21:42:28 sthen Exp $-},
+	{-$OpenBSD: MAKEDEV.md,v 1.62 2015/12/21 22:15:53 sf Exp $-},
 etc.MACHINE)dnl
 dnl
 dnl Copyright (c) 2001-2006 Todd T. Fries <todd@OpenBSD.org>
@@ -39,6 +39,7 @@ _DEV(st, 14, 5)
 _TITLE(term)
 _DEV(com, 8)
 _DEV(ttyc, 38)
+_DEV(ttyVI, 94)
 _TITLE(pty)
 _DEV(ptm, 81)
 _DEV(pty, 6)
@@ -130,5 +131,6 @@ target(all, bktr, 0)dnl
 target(all, gpio, 0, 1, 2)dnl
 target(all, nvram)dnl
 target(all, drm, 0, 1, 2, 3)dnl
+target(all, ttyVI, 00, 10, 20, 30, 40)dnl
 twrget(ramd, wsdisp, ttyC, 0)dnl
 target(ramd, fd, 0)dnl
diff --git a/share/man/man4/Makefile b/share/man/man4/Makefile
index 19f64b98456..821de462c70 100644
--- a/share/man/man4/Makefile
+++ b/share/man/man4/Makefile
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.608 2015/12/09 00:34:09 mikeb Exp $
+#	$OpenBSD: Makefile,v 1.609 2015/12/21 22:15:53 sf Exp $
 
 MAN=	aac.4 ac97.4 acphy.4 \
 	acpi.4 acpiac.4 acpiasus.4 acpibat.4 acpibtn.4 acpicpu.4 acpidock.4 \
@@ -68,7 +68,7 @@ MAN=	aac.4 ac97.4 acphy.4 \
 	uvscom.4 \
 	vether.4 vga.4 vgafb.4 vge.4 \
 	viapm.4 viasio.4 vic.4 video.4 vio.4 \
-	vioblk.4 viomb.4 viornd.4 vioscsi.4 virtio.4 vlan.4 \
+	vioblk.4 viocon.4 viomb.4 viornd.4 vioscsi.4 virtio.4 vlan.4 \
 	vmt.4 vmwpvs.4 vmx.4 vnd.4 vr.4 \
 	vscsi.4 vte.4 vxlan.4 \
 	watchdog.4 wb.4 wbenv.4 wbng.4 wbsd.4 wbsio.4 wd.4 wdc.4 wdsc.4 we.4 \
diff --git a/share/man/man4/viocon.4 b/share/man/man4/viocon.4
new file mode 100644
index 00000000000..959ec255ae9
--- /dev/null
+++ b/share/man/man4/viocon.4
@@ -0,0 +1,57 @@
+.\"     $OpenBSD: viocon.4,v 1.1 2015/12/21 22:15:53 sf Exp $
+.\"
+.\" Copyright (c) 2015 Stefan Fritsch <sf@sfritsch.de>
+.\"
+.\" Permission to use, copy, modify, and distribute this software for any
+.\" purpose with or without fee is hereby granted, provided that the above
+.\" copyright notice and this permission notice appear in all copies.
+.\"
+.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.\"
+.Dd $Mdocdate: December 21 2015 $
+.Dt VIOCON 4
+.Os
+.Sh NAME
+.Nm viocon
+.Nd VirtIO console device
+.Sh SYNOPSIS
+.Cd "viocon* at virtio?"
+.Sh DESCRIPTION
+The
+.Nm
+driver provides support for the
+.Xr virtio 4
+console interface provided by KVM, QEMU, and others.
+.Pp
+It provides serial ports that are attached as ttys.
+Use as a kernel console for
+.Ox
+is not yet supported.
+The multiport feature is not yet supported.
+.Pp
+.Sh FILES
+.Bl -tag -width Pa -compact
+.It Pa /dev/ttyVI00
+.It Pa /dev/ttyVI10
+.El
+.Sh SEE ALSO
+.Xr intro 4 ,
+.Xr virtio 4 ,
+.Xr tty 4
+.Sh HISTORY
+The
+.Nm
+driver first appeared in
+.Ox 5.9 .
+.Sh AUTHORS
+.An -nosplit
+The
+.Nm
+driver was written by
+.An Stefan Fritsch Aq Mt sf@sfritsch.de .
diff --git a/sys/arch/amd64/amd64/conf.c b/sys/arch/amd64/amd64/conf.c
index 0c9c20d898e..2289de94790 100644
--- a/sys/arch/amd64/amd64/conf.c
+++ b/sys/arch/amd64/amd64/conf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: conf.c,v 1.52 2015/11/13 07:52:20 mlarkin Exp $	*/
+/*	$OpenBSD: conf.c,v 1.53 2015/12/21 22:15:53 sf Exp $	*/
 
 /*
  * Copyright (c) 1994, 1995 Charles M. Hannum.  All rights reserved.
@@ -165,6 +165,8 @@ cdev_decl(nvram);
 cdev_decl(drm);
 #include "vmm.h"
 cdev_decl(vmm);
+#include "viocon.h"
+cdev_decl(viocon);
 
 #include "wsdisplay.h"
 #include "wskbd.h"
@@ -291,6 +293,7 @@ struct cdevsw	cdevsw[] =
 	cdev_pppx_init(NPPPX,pppx),     /* 91: pppx */
 	cdev_fuse_init(NFUSE,fuse),	/* 92: fuse */
 	cdev_tun_init(NTUN,tap),	/* 93: Ethernet network tunnel */
+	cdev_tty_init(NVIOCON,viocon),  /* 94: virtio console */
 };
 int	nchrdev = nitems(cdevsw);
 
diff --git a/sys/arch/amd64/conf/GENERIC b/sys/arch/amd64/conf/GENERIC
index 072a4e8fc63..3fe8927d3f9 100644
--- a/sys/arch/amd64/conf/GENERIC
+++ b/sys/arch/amd64/conf/GENERIC
@@ -1,4 +1,4 @@
-#	$OpenBSD: GENERIC,v 1.404 2015/12/08 22:05:31 mikeb Exp $
+#	$OpenBSD: GENERIC,v 1.405 2015/12/21 22:15:53 sf Exp $
 #
 # For further information on compiling OpenBSD kernels, see the config(8)
 # man page.
@@ -624,3 +624,4 @@ vio*		at virtio?	# Virtio network device
 viomb*		at virtio?	# Virtio memory ballooning device
 viornd*		at virtio?	# Virtio entropy device
 vioscsi*	at virtio?	# Virtio SCSI device
+#viocon*		at virtio?	# Virtio console device
diff --git a/sys/dev/pci/files.pci b/sys/dev/pci/files.pci
index a29c3955dbf..0629f6bdb95 100644
--- a/sys/dev/pci/files.pci
+++ b/sys/dev/pci/files.pci
@@ -1,4 +1,4 @@
-#	$OpenBSD: files.pci,v 1.320 2015/12/08 22:04:07 mikeb Exp $
+#	$OpenBSD: files.pci,v 1.321 2015/12/21 22:15:53 sf Exp $
 #	$NetBSD: files.pci,v 1.20 1996/09/24 17:47:15 christos Exp $
 #
 # Config file and device description for machine-independent PCI code.
@@ -822,6 +822,10 @@ device	vioblk: scsi
 attach	vioblk at virtio
 file	dev/pci/vioblk.c		vioblk
 
+device	viocon
+attach	viocon at virtio
+file	dev/pci/viocon.c		viocon		needs-flag
+
 device	viomb
 attach	viomb at virtio
 file	dev/pci/viomb.c			viomb
diff --git a/sys/dev/pci/viocon.c b/sys/dev/pci/viocon.c
new file mode 100644
index 00000000000..cb8a3228a24
--- /dev/null
+++ b/sys/dev/pci/viocon.c
@@ -0,0 +1,618 @@
+/*	$OpenBSD: viocon.c,v 1.1 2015/12/21 22:15:53 sf Exp $	*/
+
+/*
+ * Copyright (c) 2013-2015 Stefan Fritsch <sf@sfritsch.de>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/timeout.h>
+#include <machine/bus.h>
+#include <sys/device.h>
+#include <sys/conf.h>
+#include <sys/tty.h>
+#include <dev/pci/pcivar.h>
+#include <dev/pci/virtioreg.h>
+#include <dev/pci/virtiovar.h>
+
+
+/* features */
+#define	VIRTIO_CONSOLE_F_SIZE		(1<<0)
+#define	VIRTIO_CONSOLE_F_MULTIPORT	(1<<1)
+#define	VIRTIO_CONSOLE_F_EMERG_WRITE 	(1<<2)
+
+/* config space */
+#define VIRTIO_CONSOLE_COLS		0	/* 16 bits */
+#define VIRTIO_CONSOLE_ROWS		2	/* 16 bits */
+#define VIRTIO_CONSOLE_MAX_NR_PORTS	4	/* 32 bits */
+#define VIRTIO_CONSOLE_EMERG_WR		8	/* 32 bits */
+
+#define VIOCON_DEBUG	0
+
+#if VIOCON_DEBUG
+#define DBGPRINT(fmt, args...) printf("%s: " fmt "\n", __func__, ## args)
+#else
+#define DBGPRINT(fmt, args...)
+#endif
+
+struct virtio_feature_name viocon_feature_names[] = {
+	{ VIRTIO_CONSOLE_F_SIZE,	"Size" },
+	{ VIRTIO_CONSOLE_F_MULTIPORT,	"MultiPort" },
+	{ VIRTIO_CONSOLE_F_EMERG_WRITE,	"EmergWrite" },
+	{ 0, 				NULL },
+};
+
+struct virtio_console_control {
+	uint32_t id;	/* Port number */
+
+#define	VIRTIO_CONSOLE_DEVICE_READY	0
+#define	VIRTIO_CONSOLE_PORT_ADD		1
+#define	VIRTIO_CONSOLE_PORT_REMOVE	2
+#define	VIRTIO_CONSOLE_PORT_READY	3
+#define	VIRTIO_CONSOLE_CONSOLE_PORT	4
+#define	VIRTIO_CONSOLE_RESIZE		5
+#define	VIRTIO_CONSOLE_PORT_OPEN	6
+#define	VIRTIO_CONSOLE_PORT_NAME	7
+	uint16_t event;
+
+	uint16_t value;
+};
+
+struct virtio_console_control_resize {
+	/* yes, the order is different than in config space */
+	uint16_t rows;
+	uint16_t cols;
+};
+
+#define	BUFSIZE		128
+CTASSERT(BUFSIZE < TTHIWATMINSPACE);
+
+#define VIOCONUNIT(x)	(minor(x) >> 4)
+#define VIOCONPORT(x)	(minor(x) & 0x0f)
+
+struct viocon_port {
+	struct viocon_softc	*vp_sc;
+	struct virtqueue	*vp_rx;
+	struct virtqueue	*vp_tx;
+	void			*vp_si;
+	struct tty		*vp_tty;
+	const char 		*vp_name;
+	bus_dma_segment_t	 vp_dmaseg;
+	bus_dmamap_t		 vp_dmamap;
+#ifdef NOTYET
+	unsigned int		 vp_host_open:1;	/* XXX needs F_MULTIPORT */
+	unsigned int		 vp_guest_open:1;	/* XXX needs F_MULTIPORT */
+	unsigned int		 vp_is_console:1;	/* XXX needs F_MULTIPORT */
+#endif
+	unsigned int		 vp_iflow:1;		/* rx flow control */
+	uint16_t		 vp_rows;
+	uint16_t		 vp_cols;
+	u_char			*vp_rx_buf;
+	u_char			*vp_tx_buf;
+};
+
+struct viocon_softc {
+	struct device		 sc_dev;
+	struct virtio_softc	*sc_virtio;
+
+	struct virtqueue        *sc_c_vq_rx;
+	struct virtqueue        *sc_c_vq_tx;
+
+	unsigned int		 sc_max_ports;
+	struct viocon_port	**sc_ports;
+
+	bus_dmamap_t		 sc_dmamap;
+};
+
+int	viocon_match(struct device *, void *, void *);
+void	viocon_attach(struct device *, struct device *, void *);
+int	viocon_tx_intr(struct virtqueue *);
+int	viocon_tx_drain(struct viocon_port *, struct virtqueue *vq);
+int	viocon_rx_intr(struct virtqueue *);
+void	viocon_rx_soft(void *);
+void	viocon_rx_fill(struct viocon_port *);
+int	viocon_port_create(struct viocon_softc *, int);
+void	vioconstart(struct tty *);
+int	vioconhwiflow(struct tty *, int);
+int	vioconparam(struct tty *, struct termios *);
+int	vioconopen(dev_t, int, int, struct proc *);
+int	vioconclose(dev_t, int, int, struct proc *);
+int	vioconread(dev_t, struct uio *, int);
+int	vioconwrite(dev_t, struct uio *, int);
+int	vioconstop(struct tty *, int);
+int	vioconioctl(dev_t, u_long, caddr_t, int, struct proc *);
+struct tty	*viocontty(dev_t dev);
+
+struct cfattach viocon_ca = {
+	sizeof(struct viocon_softc),
+	viocon_match,
+	viocon_attach,
+	NULL
+};
+
+struct cfdriver viocon_cd = {
+	NULL, "viocon", DV_TTY
+};
+
+static inline struct viocon_softc *
+dev2sc(dev_t dev)
+{
+	return viocon_cd.cd_devs[VIOCONUNIT(dev)];
+}
+
+static inline struct viocon_port *
+dev2port(dev_t dev)
+{
+	return dev2sc(dev)->sc_ports[VIOCONPORT(dev)];
+}
+
+int viocon_match(struct device *parent, void *match, void *aux)
+{
+	struct virtio_softc *va = aux;
+	if (va->sc_childdevid == PCI_PRODUCT_VIRTIO_CONSOLE)
+		return 1;
+	return 0;
+}
+
+void
+viocon_attach(struct device *parent, struct device *self, void *aux)
+{
+	struct viocon_softc *sc = (struct viocon_softc *)self;
+	struct virtio_softc *vsc = (struct virtio_softc *)parent;
+	int maxports = 1;
+
+	if (vsc->sc_child)
+		panic("already attached to something else");
+	vsc->sc_child = self;
+	vsc->sc_ipl = IPL_TTY;
+	vsc->sc_intrhand = virtio_vq_intr;
+	vsc->sc_config_change = 0;
+	sc->sc_virtio = vsc;
+	sc->sc_max_ports = maxports;
+
+	vsc->sc_vqs = malloc(2 * (maxports + 1) * sizeof(struct virtqueue), M_DEVBUF,
+	    M_WAITOK|M_CANFAIL|M_ZERO);
+	sc->sc_ports = malloc(maxports * sizeof(sc->sc_ports[0]), M_DEVBUF,
+	    M_WAITOK|M_CANFAIL|M_ZERO);
+	if (vsc->sc_vqs == NULL || sc->sc_ports == NULL) {
+		printf("\n%s: Cannot allocate memory\n", __func__);
+		goto err;
+	}
+
+	virtio_negotiate_features(vsc, VIRTIO_CONSOLE_F_SIZE,
+	    viocon_feature_names);
+
+	printf("\n");
+	DBGPRINT("softc: %p\n", sc);
+	if (viocon_port_create(sc, 0) != 0) {
+		printf("\n%s: viocon_port_create failed\n", __func__);
+		goto err;
+	}
+	viocon_rx_fill(sc->sc_ports[0]);
+
+	return;
+err:
+	vsc->sc_child = VIRTIO_CHILD_ERROR;
+	if (vsc->sc_vqs)
+		free(vsc->sc_vqs, M_DEVBUF, 2 * (maxports + 1) * sizeof(struct virtqueue));
+	if (sc->sc_ports)
+		free(sc->sc_ports, M_DEVBUF, maxports * sizeof(sc->sc_ports[0]));
+}
+
+int
+viocon_port_create(struct viocon_softc *sc, int portidx)
+{
+	struct virtio_softc *vsc = sc->sc_virtio;
+	int rxidx, txidx, allocsize, nsegs;
+	char name[6];
+	struct viocon_port *vp;
+	caddr_t kva;
+	struct tty *tp;
+
+	vp = malloc(sizeof(*vp), M_DEVBUF, M_WAITOK|M_CANFAIL|M_ZERO);
+	if (vp == NULL)
+		return ENOMEM;
+	sc->sc_ports[portidx] = vp;
+	vp->vp_sc = sc;
+	DBGPRINT("vp: %p\n", vp);
+
+	if (portidx == 0)
+		rxidx = 0;
+	else
+		rxidx = 2 * (portidx + 1);
+	txidx = rxidx + 1;
+
+	snprintf(name, sizeof(name), "p%drx", portidx);
+	if (virtio_alloc_vq(vsc, &vsc->sc_vqs[rxidx], rxidx, BUFSIZE, 1,
+	    name) != 0) {
+		printf("\nCan't alloc %s virtqueue\n", name);
+		goto err;
+	}
+	vp->vp_rx = &vsc->sc_vqs[rxidx];
+	vp->vp_rx->vq_done = viocon_rx_intr;
+	vp->vp_si = softintr_establish(IPL_TTY, viocon_rx_soft, vp);
+	DBGPRINT("rx: %p\n", vp->vp_rx);
+
+	snprintf(name, sizeof(name), "p%dtx", portidx);
+	if (virtio_alloc_vq(vsc, &vsc->sc_vqs[txidx], txidx, BUFSIZE, 1,
+	    name) != 0) {
+		printf("\nCan't alloc %s virtqueue\n", name);
+		goto err;
+	}
+	vp->vp_tx = &vsc->sc_vqs[txidx];
+	vp->vp_tx->vq_done = viocon_tx_intr;
+	DBGPRINT("tx: %p\n", vp->vp_tx);
+
+	vsc->sc_nvqs += 2;
+
+	allocsize = (vp->vp_rx->vq_num + vp->vp_tx->vq_num) * BUFSIZE;
+
+	if (bus_dmamap_create(vsc->sc_dmat, allocsize, 1, allocsize, 0,
+	    BUS_DMA_NOWAIT | BUS_DMA_ALLOCNOW, &vp->vp_dmamap) != 0)
+		goto err;
+	if (bus_dmamem_alloc(vsc->sc_dmat, allocsize, 8, 0, &vp->vp_dmaseg,
+	    1, &nsegs, BUS_DMA_NOWAIT | BUS_DMA_ZERO) != 0)
+		goto err;
+	if (bus_dmamem_map(vsc->sc_dmat, &vp->vp_dmaseg, nsegs,
+	    allocsize, &kva, BUS_DMA_NOWAIT) != 0)
+		goto err;
+	if (bus_dmamap_load(vsc->sc_dmat, vp->vp_dmamap, kva,
+	    allocsize, NULL, BUS_DMA_NOWAIT) != 0)
+		goto err;
+	vp->vp_rx_buf = (unsigned char *)kva;
+	/*
+	 * XXX use only a small circular tx buffer instead of many BUFSIZE buffers?
+	 */
+	vp->vp_tx_buf = vp->vp_rx_buf + vp->vp_rx->vq_num * BUFSIZE;
+
+	if (vsc->sc_features & VIRTIO_CONSOLE_F_SIZE) {
+		vp->vp_cols = virtio_read_device_config_2(vsc,
+		    VIRTIO_CONSOLE_COLS);
+		vp->vp_rows = virtio_read_device_config_2(vsc,
+		    VIRTIO_CONSOLE_ROWS);
+	}
+
+	tp = ttymalloc(1000000);
+	tp->t_oproc = vioconstart;
+	tp->t_param = vioconparam;
+	tp->t_hwiflow = vioconhwiflow;
+	tp->t_dev = (sc->sc_dev.dv_unit << 4) | portidx;
+	vp->vp_tty = tp;
+	DBGPRINT("tty: %p\n", tp);
+
+	virtio_start_vq_intr(vsc, vp->vp_rx);
+	virtio_start_vq_intr(vsc, vp->vp_tx);
+
+	return 0;
+err:
+	panic("%s failed", __func__);
+	return -1;
+}
+
+int
+viocon_tx_drain(struct viocon_port *vp, struct virtqueue *vq)
+{
+	struct virtio_softc *vsc = vq->vq_owner;
+	int ndone = 0, len, slot;
+
+	splassert(IPL_TTY);
+	while (virtio_dequeue(vsc, vq, &slot, &len) == 0) {
+		bus_dmamap_sync(vsc->sc_dmat, vp->vp_dmamap,
+		    vp->vp_tx_buf - vp->vp_rx_buf + slot * BUFSIZE, BUFSIZE,
+		    BUS_DMASYNC_POSTREAD);
+		virtio_dequeue_commit(vq, slot);
+		ndone++;
+	}
+	return ndone;
+}
+
+int
+viocon_tx_intr(struct virtqueue *vq)
+{
+	struct virtio_softc *vsc = vq->vq_owner;
+	struct viocon_softc *sc = (struct viocon_softc *)vsc->sc_child;
+	int ndone = 0;
+	int portidx = (vq->vq_index - 1) / 2;
+	struct viocon_port *vp = sc->sc_ports[portidx];
+	struct tty *tp = vp->vp_tty;
+
+	splassert(IPL_TTY);
+	ndone = viocon_tx_drain(vp, vq);
+	if (ndone && ISSET(tp->t_state, TS_BUSY)) {
+		CLR(tp->t_state, TS_BUSY);
+		linesw[tp->t_line].l_start(tp);
+	}
+
+	return 1;
+}
+
+void
+viocon_rx_fill(struct viocon_port *vp)
+{
+	struct virtqueue *vq = vp->vp_rx;
+	struct virtio_softc *vsc = vp->vp_sc->sc_virtio;
+	int r, slot, ndone = 0;
+
+	while ((r = virtio_enqueue_prep(vq, &slot)) == 0) {
+		if (virtio_enqueue_reserve(vq, slot, 1) != 0)
+			break;
+		bus_dmamap_sync(vsc->sc_dmat, vp->vp_dmamap, slot * BUFSIZE,
+		    BUFSIZE, BUS_DMASYNC_PREREAD);
+		virtio_enqueue_p(vq, slot, vp->vp_dmamap, slot * BUFSIZE,
+		    BUFSIZE, 0);
+		virtio_enqueue_commit(vsc, vq, slot, 0);
+		ndone++;
+	}
+	KASSERT(r == 0 || r == EAGAIN);
+	if (ndone > 0)
+		virtio_notify(vsc, vq);
+}
+
+int
+viocon_rx_intr(struct virtqueue *vq)
+{
+	struct virtio_softc *vsc = vq->vq_owner;
+	struct viocon_softc *sc = (struct viocon_softc *)vsc->sc_child;
+	int portidx = (vq->vq_index - 1) / 2;
+	struct viocon_port *vp = sc->sc_ports[portidx];
+
+	softintr_schedule(vp->vp_si);
+	return 1;
+}
+
+void
+viocon_rx_soft(void *arg)
+{
+	struct viocon_port *vp = arg;
+	struct virtqueue *vq = vp->vp_rx;
+	struct virtio_softc *vsc = vq->vq_owner;
+	struct tty *tp = vp->vp_tty;
+	int slot, len, i;
+	u_char *p;
+
+	while (!vp->vp_iflow && virtio_dequeue(vsc, vq, &slot, &len) == 0) {
+		bus_dmamap_sync(vsc->sc_dmat, vp->vp_dmamap,
+		    slot * BUFSIZE, BUFSIZE, BUS_DMASYNC_POSTREAD);
+		p = vp->vp_rx_buf + slot * BUFSIZE;
+		for (i = 0; i < len; i++)
+			(*linesw[tp->t_line].l_rint)(*p++, tp);
+		virtio_dequeue_commit(vq, slot);
+	}
+
+	viocon_rx_fill(vp);
+
+	return;
+}
+
+void
+vioconstart(struct tty *tp)
+{
+	struct viocon_softc *sc = dev2sc(tp->t_dev);
+	struct virtio_softc *vsc;
+	struct viocon_port *vp = dev2port(tp->t_dev);
+	struct virtqueue *vq;
+	u_char *buf;
+	int s, cnt, slot, ret, ndone;
+
+	vsc = sc->sc_virtio;
+	vq = vp->vp_tx;
+
+	s = spltty();
+
+	ndone = viocon_tx_drain(vp, vq);
+	if (ISSET(tp->t_state, TS_BUSY)) {
+		if (ndone > 0)
+			CLR(tp->t_state, TS_BUSY);
+		else
+			goto out;
+	}
+	if (ISSET(tp->t_state, TS_TIMEOUT | TS_TTSTOP))
+		goto out;
+
+	if (tp->t_outq.c_cc == 0)
+		goto out;
+	ndone = 0;
+
+	while (tp->t_outq.c_cc > 0) {
+		ret = virtio_enqueue_prep(vq, &slot);
+		if (ret == EAGAIN)
+			break;
+		KASSERT(ret == 0);
+		ret = virtio_enqueue_reserve(vq, slot, 1);
+		KASSERT(ret == 0);
+		buf = vp->vp_tx_buf + slot * BUFSIZE;
+		cnt = q_to_b(&tp->t_outq, buf, BUFSIZE);
+		bus_dmamap_sync(vsc->sc_dmat, vp->vp_dmamap,
+		    vp->vp_tx_buf - vp->vp_rx_buf + slot * BUFSIZE, cnt,
+		    BUS_DMASYNC_PREWRITE);
+		virtio_enqueue_p(vq, slot, vp->vp_dmamap,
+		    vp->vp_tx_buf - vp->vp_rx_buf + slot * BUFSIZE, cnt, 1);
+		virtio_enqueue_commit(vsc, vq, slot, 0);
+		ndone++;
+	}
+	if (ret == EAGAIN)
+		SET(tp->t_state, TS_BUSY);
+	if (ndone > 0)
+		virtio_notify(vsc, vq);
+	ttwakeupwr(tp);
+out:
+	splx(s);
+}
+
+int
+vioconhwiflow(struct tty *tp, int stop)
+{
+	struct viocon_port *vp = dev2port(tp->t_dev);
+	int s;
+
+	s = spltty();
+	vp->vp_iflow = stop;
+	if (stop) {
+		virtio_stop_vq_intr(vp->vp_sc->sc_virtio, vp->vp_rx);
+	} else {
+		virtio_start_vq_intr(vp->vp_sc->sc_virtio, vp->vp_rx);
+		softintr_schedule(vp->vp_si);
+	}
+	splx(s);
+	return 1;
+}
+
+int
+vioconparam(struct tty *tp, struct termios *t)
+{
+	tp->t_ispeed = t->c_ispeed;
+	tp->t_ospeed = t->c_ospeed;
+	tp->t_cflag = t->c_cflag;
+
+	vioconstart(tp);
+	return 0;
+}
+
+int
+vioconopen(dev_t dev, int flag, int mode, struct proc *p)
+{
+	int unit = VIOCONUNIT(dev);
+	int port = VIOCONPORT(dev);
+	struct viocon_softc *sc;
+	struct viocon_port *vp;
+	struct tty *tp;
+	int s, error;
+
+	if (unit >= viocon_cd.cd_ndevs)
+		return (ENXIO);
+	sc = viocon_cd.cd_devs[unit];
+	if (sc == NULL)
+		return (ENXIO);
+	if (ISSET(sc->sc_dev.dv_flags, DVF_ACTIVE) == 0)
+		return (ENXIO);
+
+	s = spltty();
+	if (port >= sc->sc_max_ports) {
+		splx(s);
+		return (ENXIO);
+	}
+	vp = sc->sc_ports[port];
+	tp = vp->vp_tty;
+#ifdef NOTYET
+	vp->vp_guest_open = 1;
+#endif
+	splx(s);
+
+	if (!ISSET(tp->t_state, TS_ISOPEN)) {
+		SET(tp->t_state, TS_WOPEN);
+		ttychars(tp);
+		tp->t_ispeed = 1000000;
+		tp->t_ospeed = 1000000;
+		tp->t_cflag = TTYDEF_CFLAG|CLOCAL|CRTSCTS;
+		tp->t_iflag = TTYDEF_IFLAG;
+		tp->t_oflag = TTYDEF_OFLAG;
+		tp->t_lflag = TTYDEF_LFLAG;
+		if (vp->vp_cols != 0) {
+			tp->t_winsize.ws_col = vp->vp_cols;
+			tp->t_winsize.ws_row = vp->vp_rows;
+		}
+
+		s = spltty();
+		vioconparam(tp, &tp->t_termios);
+		ttsetwater(tp);
+		splx(s);
+	}
+	else if (ISSET(tp->t_state, TS_XCLUDE) && suser(p, 0) != 0) {
+		return (EBUSY);
+	}
+
+	error = linesw[tp->t_line].l_open(dev, tp, p);
+	return error;
+}
+
+int
+vioconclose(dev_t dev, int flag, int mode, struct proc *p)
+{
+	struct viocon_port *vp = dev2port(dev);
+	struct tty *tp = vp->vp_tty;
+	int s;
+
+	if (!ISSET(tp->t_state, TS_ISOPEN))
+		return 0;
+
+	linesw[tp->t_line].l_close(tp, flag, p);
+	s = spltty();
+#ifdef NOTYET
+	vp->vp_guest_open = 0;
+#endif
+	CLR(tp->t_state, TS_BUSY | TS_FLUSH);
+	ttyclose(tp);
+	splx(s);
+
+	return 0;
+}
+
+int
+vioconread(dev_t dev, struct uio *uio, int flag)
+{
+	struct viocon_port *vp = dev2port(dev);
+	struct tty *tp = vp->vp_tty;
+
+	return linesw[tp->t_line].l_read(tp, uio, flag);
+}
+
+int
+vioconwrite(dev_t dev, struct uio *uio, int flag)
+{
+	struct viocon_port *vp = dev2port(dev);
+	struct tty *tp = vp->vp_tty;
+
+	return linesw[tp->t_line].l_write(tp, uio, flag);
+}
+
+struct tty *
+viocontty(dev_t dev)
+{
+	struct viocon_port *vp = dev2port(dev);
+
+	return vp->vp_tty;
+}
+
+int
+vioconstop(struct tty *tp, int flag)
+{
+	int s;
+
+	s = spltty();
+	if (ISSET(tp->t_state, TS_BUSY))
+		if (!ISSET(tp->t_state, TS_TTSTOP))
+			SET(tp->t_state, TS_FLUSH);
+	splx(s);
+	return 0;
+}
+
+int
+vioconioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
+{
+	struct viocon_port *vp = dev2port(dev);
+	struct tty *tp;
+	int error1, error2;
+
+	tp = vp->vp_tty;
+
+	error1 = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, p);
+	if (error1 >= 0)
+		return error1;
+	error2 = ttioctl(tp, cmd, data, flag, p);
+	if (error2 >= 0)
+		return error2;
+	return ENOTTY;
+}