On Fri, Jun 05, 2009 at 03:30:07PM -0400, Gregory Haskins wrote: > Hi Michael, > FYI: This was a patch I started to put together around the time vbus-v3 was > released to demonstrate the interface for virtio devices that we needed. I > just wanted to get it out to you so you have a working example to look at > what it takes to write something like virtio-net against virtio-vbus.
Thanks, Gregory, I'll take a look. > What I will do next is make a minor v3.1 release of vbus on top of kvm.git > and get this patch cleaned up so we can actually run it. Note that v3.1 > will just a minor port of v3 to kvm.git/HEAD, not the new iosignalfd/irqfd > stuff that I have queued for v4. Thats not ready for prime-time yet. > > ---------------------------- > > virtio: add a virtio-console to the vbus backend > > A console probably doesnt need to live in the kernel since it is generally > not performance limited. However, its also a very simple example, so lets > make a vbus backend to demonstrate the virtio interfaces. > > Signed-off-by: Gregory Haskins <[email protected]> > --- > > drivers/vbus/devices/Kconfig | 9 > drivers/vbus/devices/Makefile | 1 > drivers/vbus/devices/virtio-console-backend.c | 461 > +++++++++++++++++++++++++ > 3 files changed, 471 insertions(+), 0 deletions(-) > create mode 100644 drivers/vbus/devices/virtio-console-backend.c > > diff --git a/drivers/vbus/devices/Kconfig b/drivers/vbus/devices/Kconfig > index 64e4731..0239e86 100644 > --- a/drivers/vbus/devices/Kconfig > +++ b/drivers/vbus/devices/Kconfig > @@ -15,3 +15,12 @@ config VBUS_VENETTAP > > If unsure, say N > > +config VBUS_VIRTIO_CONSOLE > + tristate "Virtual-Bus Backend for virtio-console drivers" > + depends on VBUS_DEVICES > + select VBUS_VIRTIO_BACKEND > + default n > + help > + Provides a virtual console device within the vbus infrastructure > + > + If unsure, say N > diff --git a/drivers/vbus/devices/Makefile b/drivers/vbus/devices/Makefile > index 2ea7d2a..fd51cb6 100644 > --- a/drivers/vbus/devices/Makefile > +++ b/drivers/vbus/devices/Makefile > @@ -1 +1,2 @@ > obj-$(CONFIG_VBUS_VENETTAP) += venet-tap.o > +obj-$(CONFIG_VBUS_VIRTIO_CONSOLE) += virtio-console-backend.o > diff --git a/drivers/vbus/devices/virtio-console-backend.c > b/drivers/vbus/devices/virtio-console-backend.c > new file mode 100644 > index 0000000..bf30016 > --- /dev/null > +++ b/drivers/vbus/devices/virtio-console-backend.c > @@ -0,0 +1,461 @@ > +/* > + * virtio-console for the vbus backend > + * > + * Copyright (C) 2009 Novell, Gregory Haskins <[email protected]> > + * > + * This file is free software; you can redistribute it and/or modify > + * it under the terms of version 2 of the GNU General Public License > + * as published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program; if not, write to the Free Software Foundation, > + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. > + */ > + > +#include <linux/module.h> > +#include <linux/init.h> > +#include <linux/moduleparam.h> > + > +#include <linux/cdev.h> > +#include <linux/fs.h> > +#include <linux/major.h> > + > +#include <linux/vbus_device.h> > +#include <linux/virtio_vbus.h> > +#include <linux/virtio_console.h> > + > +MODULE_AUTHOR("Gregory Haskins"); > +MODULE_LICENSE("GPL"); > + > +#undef PDEBUG /* undef it, just in case */ > +#ifdef VIRTIO_CONSOLE_DEBUG > +# define PDEBUG(fmt, args...) printk(KERN_DEBUG "virtio-console: " fmt, ## > args) > +#else > +# define PDEBUG(fmt, args...) /* not debugging: nothing */ > +#endif > + > +struct _virtio_console { > + spinlock_t lock; > + char *name; > + dev_t devno; > + struct cdev cdev; > + struct vbus_device dev; > + struct virtio_device_interface intf; > + struct virtio_connection conn; > + struct vbus_memctx *ctx; > + struct virtqueue *rx; > + struct virtqueue *tx; > + int enabled:1; > + int connected:1; > + int opened:1; > + int tty:1; > + int link:1; > +}; > + > +static struct _virtio_console * > +conn_to_priv(struct virtio_connection *conn) > +{ > + return container_of(conn, struct _virtio_console, conn); > +} > + > +static struct _virtio_console * > +intf_to_priv(struct virtio_device_interface *intf) > +{ > + return container_of(intf, struct _virtio_console, intf); > +} > + > +static struct _virtio_console * > +vdev_to_priv(struct vbus_device *vdev) > +{ > + return container_of(vdev, struct _virtio_console, dev); > +} > + > +/* > + * -------------------------------------------- > + * Driver connection > + * -------------------------------------------- > + */ > + > +static void > +_virtio_console_add_vq(struct virtio_connection *vconn, int index, > + struct virtqueue *vq) > +{ > + struct _virtio_console *priv = conn_to_priv(vconn); > + > + switch (index) { > + case 0: > + if (!priv->rx) > + priv->rx = vq; > + break; > + case 1: > + if (!priv->tx) > + priv->tx = vq; > + break; > + default: > + break; > + } > +} > + > +static void > +_virtio_console_del_vq(struct virtio_connection *vconn, int index) > +{ > + struct _virtio_console *priv = conn_to_priv(vconn); > + > + switch (index) { > + case 0: > + priv->rx = NULL; > + break; > + case 1: > + priv->tx = NULL; > + break; > + default: > + break; > + } > +} > + > +static void > +_virtio_console_notify_vq(struct virtio_connection *vconn, int index) > +{ > + > +} > + > +/* > + * This is called whenever the driver closes all references to our device > + */ > +static void > +_virtio_console_release(struct virtio_connection *conn) > +{ > + struct _virtio_console *priv = conn_to_priv(conn); > + > + priv->opened = false; > + vbus_memctx_put(priv->ctx); > +} > + > +static struct virtio_connection_ops virtio_console_connection_ops = { > + .add_vq = _virtio_console_add_vq, > + .del_vq = _virtio_console_del_vq, > + .notify_vq = _virtio_console_notify_vq, > + .release = _virtio_console_release, > +}; > + > +/* > + * -------------------------------------------- > + * Interface > + * -------------------------------------------- > + */ > + > +/* > + * This is called whenever a driver wants to open our device_interface > + * for communication. The connection is represented by a > + * virtio_connection object. It is up to the implementation to decide > + * if it allows more than one connection at a time. This simple example > + * does not. > + */ > +static int > +virtio_console_intf_open(struct virtio_device_interface *intf, > + struct vbus_memctx *ctx, > + struct virtio_connection **conn) > +{ > + struct _virtio_console *priv = intf_to_priv(intf); > + unsigned long flags; > + > + PDEBUG("open\n"); > + > + spin_lock_irqsave(&priv->lock, flags); > + > + /* > + * We only allow one connection to this device > + */ > + if (priv->opened) { > + spin_unlock_irqrestore(&priv->lock, flags); > + return -EBUSY; > + } > + > + memset(&priv->conn, 0, sizeof(priv->conn)); > + priv->conn.ops = &virtio_console_connection_ops; > + > + priv->opened = true; > + priv->ctx = ctx; > + > + vbus_memctx_get(ctx); > + > + spin_unlock_irqrestore(&priv->lock, flags); > + > + *conn = &priv->conn; > + > + return 0; > +} > + > +static void > +virtio_console_intf_release(struct virtio_device_interface *intf) > +{ > + kobject_put(intf->parent->dev->kobj); /* acquired on bus-connect */ > +} > + > +static struct virtio_device_interface_ops virtio_console_intf_ops = { > + .open = virtio_console_intf_open, > + .release = virtio_console_intf_release, > +}; > + > +/* > + * -------------------------------------------- > + * Bus+Device interaction > + * -------------------------------------------- > + */ > + > +/* > + * This is called whenever the admin creates a symbolic link between > + * a bus in /config/vbus/buses and our device. It represents a bus > + * connection. Your device can chose to allow more than one bus to > + * connect, or it can restrict it to one bus. It can also choose to > + * register one or more device_interfaces on each bus that it > + * successfully connects to. > + * > + * This example device only registers a single interface > + */ > +static int > +virtio_console_device_bus_connect(struct vbus_device *dev, struct vbus *vbus) > +{ > + struct _virtio_console *priv = vdev_to_priv(dev); > + struct virtio_device_interface *intf = &priv->intf; > + > + /* We only allow one bus to connect */ > + if (priv->connected) > + return -EBUSY; > + > + kobject_get(dev->kobj); /* released when we release the intf */ > + > + intf->id.vendor = 0x1af4; > + intf->id.device = VIRTIO_ID_CONSOLE; > + > + intf->ops = &virtio_console_intf_ops; > + > + priv->connected = true; > + > + /* > + * Our example only registers one interface. If you need > + * more, simply call interface_register() multiple times > + */ > + return virtio_device_interface_register(dev, vbus, intf); > +} > + > +/* > + * This is called whenever the admin removes the symbolic link between > + * a bus in /config/vbus/buses and our device. > + */ > +static int > +virtio_console_device_bus_disconnect(struct vbus_device *dev, struct vbus > *vbus) > +{ > + struct _virtio_console *priv = vdev_to_priv(dev); > + struct virtio_device_interface *intf = &priv->intf; > + > + if (!priv->connected) > + return -EINVAL; > + > + virtio_device_interface_unregister(intf); > + > + priv->connected = false; > + > + return 0; > +} > + > +static void > +virtio_console_device_release(struct vbus_device *dev) > +{ > + struct _virtio_console *priv = vdev_to_priv(dev); > + > + unregister_chrdev_region(priv->devno, 1); > + kfree(priv); > + > + module_put(THIS_MODULE); > +} > + > + > +static struct vbus_device_ops virtio_console_device_ops = { > + .bus_connect = virtio_console_device_bus_connect, > + .bus_disconnect = virtio_console_device_bus_disconnect, > + .release = virtio_console_device_release, > +}; > + > +#define VIRTIO_CONSOLE_TYPE "virtio-console" > + > +/* > + * -------------------------------------------- > + * Character Device > + * -------------------------------------------- > + */ > + > +static int > +virtio_console_chardev_open(struct inode *inode, struct file *filp) > +{ > + struct _virtio_console *priv; > + > + priv = container_of(inode->i_cdev, struct _virtio_console, cdev); > + > + kobject_get(priv->dev.kobj); /* released when we release the cd */ > + filp->private_data = priv; > + > + return 0; > +} > + > +static ssize_t > +virtio_console_chardev_read(struct file *filp, char __user *buf, size_t len, > + loff_t *ppos) > +{ > + struct _virtio_console *priv = filp->private_data; > + > + return -EINVAL; > +} > + > +static ssize_t > +virtio_console_chardev_write(struct file *filp, const char __user *buf, > + size_t len, loff_t *ppos) > +{ > + struct _virtio_console *priv = filp->private_data; > + > + return -EINVAL; > +} > + > +static int > +virtio_console_chardev_release(struct inode *inode, struct file *filp) > +{ > + struct _virtio_console *priv = filp->private_data; > + > + kobject_put(priv->dev.kobj); > + > + return 0; > +} > + > +static const struct file_operations virtio_console_chardev_ops = { > + .open = virtio_console_chardev_open, > + .read = virtio_console_chardev_read, > + .write = virtio_console_chardev_write, > + .release = virtio_console_chardev_release, > +}; > + > +/* > + * -------------------------------------------- > + * Attributes > + * -------------------------------------------- > + */ > + > +/* > + * Interface attributes show up as files under > + * /sys/vbus/devices/$devid > + */ > + > +static ssize_t > +devno_show(struct vbus_device *dev, struct vbus_device_attribute *attr, > + char *buf) > +{ > + struct _virtio_console *priv = vdev_to_priv(dev); > + > + return snprintf(buf, PAGE_SIZE, "%d:%d\n", > + MAJOR(priv->devno), MINOR(priv->devno)); > +} > + > +static struct vbus_device_attribute attr_devno = > + __ATTR_RO(devno); > + > +static struct attribute *attrs[] = { > + &attr_devno.attr, > + NULL, > +}; > + > +static struct attribute_group virtio_console_attr_group = { > + .attrs = attrs, > +}; > + > +/* > + * -------------------------------------------- > + * Device > + * -------------------------------------------- > + */ > + > +/* > + * This is called whenever the admin instantiates our devclass via > + * "mkdir /config/vbus/devices/$(inst)/virtio-console" > + */ > +static int > +virtio_console_device_create(struct vbus_devclass *dc, > + struct vbus_device **vdev) > +{ > + struct _virtio_console *priv; > + struct vbus_device *_vdev; > + int ret; > + > + priv = kzalloc(sizeof(*priv), GFP_KERNEL); > + if (!priv) > + return -ENOMEM; > + > + spin_lock_init(&priv->lock); > + > + /* > + * cdev init > + */ > + ret = alloc_chrdev_region(&priv->devno, TTY_MAJOR, > + 1, VIRTIO_CONSOLE_TYPE); > + if (ret < 0) > + goto out_free; > + > + cdev_init(&priv->cdev, &virtio_console_chardev_ops); > + priv->cdev.owner = THIS_MODULE; > + priv->cdev.ops = &virtio_console_chardev_ops; > + ret = cdev_add(&priv->cdev, priv->devno, 1); > + if (ret < 0) > + goto out; > + > + /* > + * vbus init > + */ > + _vdev = &priv->dev; > + > + _vdev->type = VIRTIO_CONSOLE_TYPE; > + _vdev->ops = &virtio_console_device_ops; > + _vdev->attrs = &virtio_console_attr_group; > + > + *vdev = _vdev; > + > + /* > + * We don't need a try_get because the reference is held by the > + * infrastructure during a create() operation. This is released > + * when our device is released > + */ > + __module_get(THIS_MODULE); > + > + return 0; > + > +out: > + unregister_chrdev_region(priv->devno, 1); > +out_free: > + kfree(priv); > + return ret; > +} > + > +static struct vbus_devclass_ops virtio_console_devclass_ops = { > + .create = virtio_console_device_create, > +}; > + > +static struct vbus_devclass virtio_console_devclass = { > + .name = VIRTIO_CONSOLE_TYPE, > + .ops = &virtio_console_devclass_ops, > + .owner = THIS_MODULE, > +}; > + > +static int __init virtio_console_init(void) > +{ > + return vbus_devclass_register(&virtio_console_devclass); > +} > + > +static void __exit virtio_console_cleanup(void) > +{ > + vbus_devclass_unregister(&virtio_console_devclass); > +} > + > +module_init(virtio_console_init); > +module_exit(virtio_console_cleanup); -- MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
