[Xen-devel] Re: [PATCH 2/2] xen pvfb: Para-virtual framebuffer, keyboard and pointer driver

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

Markus Armbruster wrote:
> This is a pair of Xen para-virtual frontend device drivers:
> drivers/video/xen-fbfront.c provides a framebuffer, and
> drivers/input/xen-kbdfront provides keyboard and mouse.
>   
Unless they're actually inter-dependent, could you post this as two 
separate patches?  I don't know anything about these parts of the 
kernel, so it would be nice to make it very obvious which changes are fb 
vs mouse/keyboard.
(I guess input/* vs video/* should make it obvious, but it looks like 
input has a config dependency on fb, so I'll avoid making too many 
presumptions...)
(Couple of comments below)

   J

> The backends run in dom0 user space.
>
> Signed-off-by: Markus Armbruster <armbru@xxxxxxxxxx>
>
> ---
>
>  drivers/input/Kconfig            |    9 
>  drivers/input/Makefile           |    2 
>  drivers/input/xen-kbdfront.c     |  337 +++++++++++++++++++++++
>  drivers/video/Kconfig            |   14 
>  drivers/video/Makefile           |    1 
>  drivers/video/xen-fbfront.c      |  550 +++++++++++++++++++++++++++++++++++++++
>  include/xen/interface/io/fbif.h  |  124 ++++++++
>  include/xen/interface/io/kbdif.h |  114 ++++++++
>  8 files changed, 1151 insertions(+)
>
> diff --git a/drivers/input/Kconfig b/drivers/input/Kconfig
> index 9dea14d..5f9d860 100644
> --- a/drivers/input/Kconfig
> +++ b/drivers/input/Kconfig
> @@ -149,6 +149,15 @@ config INPUT_APMPOWER
>           To compile this driver as a module, choose M here: the
>           module will be called apm-power.
>  
> +config XEN_KBDDEV_FRONTEND
> +       tristate "Xen virtual keyboard and mouse support"
> +       depends on XEN_FBDEV_FRONTEND
> +       default y
> +       help
> +         This driver implements the front-end of the Xen virtual
> +         keyboard and mouse device driver.  It communicates with a back-end
> +         in another domain.
> +
>  comment "Input Device Drivers"
>  
>  source "drivers/input/keyboard/Kconfig"
> diff --git a/drivers/input/Makefile b/drivers/input/Makefile
> index 2ae87b1..98c4f9a 100644
> --- a/drivers/input/Makefile
> +++ b/drivers/input/Makefile
> @@ -23,3 +23,5 @@ obj-$(CONFIG_INPUT_TOUCHSCREEN)       += touchscreen/
>  obj-$(CONFIG_INPUT_MISC)       += misc/
>  
>  obj-$(CONFIG_INPUT_APMPOWER)	+= apm-power.o
> +
> +obj-$(CONFIG_XEN_KBDDEV_FRONTEND)      += xen-kbdfront.o
> diff --git a/drivers/input/xen-kbdfront.c b/drivers/input/xen-kbdfront.c
> new file mode 100644
> index 0000000..84f65cf
> --- /dev/null
> +++ b/drivers/input/xen-kbdfront.c
> @@ -0,0 +1,337 @@
> +/*
> + * Xen para-virtual input device
> + *
> + * Copyright (C) 2005 Anthony Liguori <aliguori@xxxxxxxxxx>
> + * Copyright (C) 2006-2008 Red Hat, Inc., Markus Armbruster <armbru@xxxxxxxxxx>
> + *
> + *  Based on linux/drivers/input/mouse/sermouse.c
> + *
> + *  This file is subject to the terms and conditions of the GNU General Public
> + *  License. See the file COPYING in the main directory of this archive for
> + *  more details.
> + */
> +
> +/*
> + * TODO:
> + *
> + * Switch to grant tables together with xen-fbfront.c.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/errno.h>
> +#include <linux/module.h>
> +#include <linux/input.h>
> +#include <asm/xen/hypervisor.h>
> +#include <xen/events.h>
> +#include <xen/page.h>
> +#include <xen/interface/io/fbif.h>
> +#include <xen/interface/io/kbdif.h>
> +#include <xen/xenbus.h>
> +
> +struct xenkbd_info {
> +       struct input_dev *kbd;
> +       struct input_dev *ptr;
> +       struct xenkbd_page *page;
> +       int evtchn, irq;
> +       struct xenbus_device *xbdev;
> +       char phys[32];
> +};
> +
> +static int xenkbd_remove(struct xenbus_device *);
> +static int xenkbd_connect_backend(struct xenbus_device *, struct xenkbd_info 
> *);
> +static void xenkbd_disconnect_backend(struct xenkbd_info *);
> +
> +/*
> + * Note: if you need to send out events, see xenfb_do_update() for how
> + * to do that.
> + */
> +
> +static irqreturn_t input_handler(int rq, void *dev_id)
> +{
> +       struct xenkbd_info *info = dev_id;
> +       struct xenkbd_page *page = info->page;
> +       __u32 cons, prod;
> +
> +       prod = page->in_prod;
> +       if (prod == page->in_cons)
> +               return IRQ_HANDLED;
> +       rmb();                  /* ensure we see ring contents up to prod */
> +       for (cons = page->in_cons; cons != prod; cons++) {
> +               union xenkbd_in_event *event;
> +               struct input_dev *dev;
> +               event = &XENKBD_IN_RING_REF(page, cons);
> +
> +               dev = info->ptr;
> +               switch (event->type) {
> +               case XENKBD_TYPE_MOTION:
> +                       input_report_rel(dev, REL_X, event->motion.rel_x);
> +                       input_report_rel(dev, REL_Y, event->motion.rel_y);
> +                       break;
> +               case XENKBD_TYPE_KEY:
> +                       dev = NULL;
> +                       if (test_bit(event->key.keycode, info->kbd->keybit))
> +                               dev = info->kbd;
> +                       if (test_bit(event->key.keycode, info->ptr->keybit))
> +                               dev = info->ptr;
> +                       if (dev)
> +                               input_report_key(dev, event->key.keycode,
> +                                                event->key.pressed);
> +                       else
> +                               printk(KERN_WARNING
> +                                      "xenkbd: unhandled keycode 0x%x\n",
> +                                      event->key.keycode);
> +                       break;
> +               case XENKBD_TYPE_POS:
> +                       input_report_abs(dev, ABS_X, event->pos.abs_x);
> +                       input_report_abs(dev, ABS_Y, event->pos.abs_y);
> +                       break;
> +               }
> +               if (dev)
> +                       input_sync(dev);
> +       }
> +       mb();                   /* ensure we got ring contents */
> +       page->in_cons = cons;
> +       notify_remote_via_irq(info->irq);
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static int __devinit xenkbd_probe(struct xenbus_device *dev,
> +                                 const struct xenbus_device_id *id)
> +{
> +       int ret, i;
> +       struct xenkbd_info *info;
> +       struct input_dev *kbd, *ptr;
> +
> +       info = kzalloc(sizeof(*info), GFP_KERNEL);
> +       if (!info) {
> +               xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
> +               return -ENOMEM;
> +       }
> +       dev->dev.driver_data = info;
> +       info->xbdev = dev;
> +       snprintf(info->phys, sizeof(info->phys), "xenbus/%s", dev->nodename);
> +
> +       info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
> +       if (!info->page)
> +               goto error_nomem;
> +
> +       /* keyboard */
> +       kbd = input_allocate_device();
> +       if (!kbd)
> +               goto error_nomem;
> +       kbd->name = "Xen Virtual Keyboard";
> +       kbd->phys = info->phys;
> +       kbd->id.bustype = BUS_PCI;
> +       kbd->id.vendor = 0x5853;
> +       kbd->id.product = 0xffff;
> +       kbd->evbit[0] = BIT(EV_KEY);
> +       for (i = KEY_ESC; i < KEY_UNKNOWN; i++)
> +               set_bit(i, kbd->keybit);
> +       for (i = KEY_OK; i < KEY_MAX; i++)
> +               set_bit(i, kbd->keybit);
> +
> +       ret = input_register_device(kbd);
> +       if (ret) {
> +               input_free_device(kbd);
> +               xenbus_dev_fatal(dev, ret, "input_register_device(kbd)");
> +               goto error;
> +       }
> +       info->kbd = kbd;
> +
> +       /* pointing device */
> +       ptr = input_allocate_device();
> +       if (!ptr)
> +               goto error_nomem;
> +       ptr->name = "Xen Virtual Pointer";
> +       ptr->phys = info->phys;
> +       ptr->id.bustype = BUS_PCI;
> +       ptr->id.vendor = 0x5853;
> +       ptr->id.product = 0xfffe;
> +       ptr->evbit[0] = BIT(EV_KEY) | BIT(EV_REL) | BIT(EV_ABS);
> +       for (i = BTN_LEFT; i <= BTN_TASK; i++)
> +               set_bit(i, ptr->keybit);
> +       ptr->relbit[0] = BIT(REL_X) | BIT(REL_Y);
> +       input_set_abs_params(ptr, ABS_X, 0, XENFB_WIDTH, 0, 0);
> +       input_set_abs_params(ptr, ABS_Y, 0, XENFB_HEIGHT, 0, 0);
> +
> +       ret = input_register_device(ptr);
> +       if (ret) {
> +               input_free_device(ptr);
> +               xenbus_dev_fatal(dev, ret, "input_register_device(ptr)");
> +               goto error;
> +       }
> +       info->ptr = ptr;
> +
> +       ret = xenkbd_connect_backend(dev, info);
> +       if (ret < 0)
> +               goto error;
> +
> +       return 0;
> +
> + error_nomem:
> +       ret = -ENOMEM;
> +       xenbus_dev_fatal(dev, ret, "allocating device memory");
> + error:
> +       xenkbd_remove(dev);
>   
This is happy if dev->info is only partially initialized?

> +       return ret;
> +}
> +
> +static int xenkbd_resume(struct xenbus_device *dev)
> +{
> +       struct xenkbd_info *info = dev->dev.driver_data;
> +
> +       xenkbd_disconnect_backend(info);
> +       memset(info->page, 0, PAGE_SIZE);
> +       return xenkbd_connect_backend(dev, info);
> +}
> +
> +static int xenkbd_remove(struct xenbus_device *dev)
> +{
> +       struct xenkbd_info *info = dev->dev.driver_data;
> +
> +       xenkbd_disconnect_backend(info);
> +       input_unregister_device(info->kbd);
> +       input_unregister_device(info->ptr);
>   
Does this free kdb and ptr?

> +       free_page((unsigned long)info->page);
> +       kfree(info);
> +       return 0;
> +}
> +
> +static int xenkbd_connect_backend(struct xenbus_device *dev,
> +                                 struct xenkbd_info *info)
> +{
> +       int ret;
> +       struct xenbus_transaction xbt;
> +
> +       ret = xenbus_alloc_evtchn(dev, &info->evtchn);
> +       if (ret)
> +               return ret;
> +       ret = bind_evtchn_to_irqhandler(info->evtchn, input_handler,
> +                                       0, dev->devicetype, info);
> +       if (ret < 0) {
> +               xenbus_free_evtchn(dev, info->evtchn);
> +               xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
> +               return ret;
> +       }
> +       info->irq = ret;
> +
> + again:
> +       ret = xenbus_transaction_start(&xbt);
> +       if (ret) {
> +               xenbus_dev_fatal(dev, ret, "starting transaction");
> +               return ret;
> +       }
> +       ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
> +                           virt_to_mfn(info->page));
> +       if (ret)
> +               goto error_xenbus;
> +       ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
> +                           info->evtchn);
> +       if (ret)
> +               goto error_xenbus;
> +       ret = xenbus_transaction_end(xbt, 0);
> +       if (ret) {
> +               if (ret == -EAGAIN)
> +                       goto again;
> +               xenbus_dev_fatal(dev, ret, "completing transaction");
> +               return ret;
> +       }
> +
> +       xenbus_switch_state(dev, XenbusStateInitialised);
> +       return 0;
> +
> + error_xenbus:
> +       xenbus_transaction_end(xbt, 1);
> +       xenbus_dev_fatal(dev, ret, "writing xenstore");
> +       return ret;
> +}
> +
> +static void xenkbd_disconnect_backend(struct xenkbd_info *info)
> +{
> +       if (info->irq >= 0)
> +               unbind_from_irqhandler(info->irq, info);
> +       info->evtchn = info->irq = -1;
> +}
> +
> +static void xenkbd_backend_changed(struct xenbus_device *dev,
> +                                  enum xenbus_state backend_state)
> +{
> +       struct xenkbd_info *info = dev->dev.driver_data;
> +       int ret, val;
> +
> +       switch (backend_state) {
> +       case XenbusStateInitialising:
> +       case XenbusStateInitialised:
> +       case XenbusStateUnknown:
> +       case XenbusStateClosed:
> +               break;
> +
> +       case XenbusStateInitWait:
> +InitWait:
> +               ret = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
> +                                  "feature-abs-pointer", "%d", &val);
> +               if (ret < 0)
> +                       val = 0;
> +               if (val) {
> +                       ret = xenbus_printf(XBT_NIL, info->xbdev->nodename,
> +                                           "request-abs-pointer", "1");
> +                       if (ret)
> +                               printk(KERN_WARNING
> +                                      "xenkbd: can't request abs-pointer");
> +               }
> +               xenbus_switch_state(dev, XenbusStateConnected);
> +               break;
> +
> +       case XenbusStateConnected:
> +               /*
> +                * Work around xenbus race condition: If backend goes
> +                * through InitWait to Connected fast enough, we can
> +                * get Connected twice here.
> +                */
> +               if (dev->state != XenbusStateConnected)
> +                       goto InitWait; /* no InitWait seen yet, fudge it */
> +               break;
> +
> +       case XenbusStateClosing:
> +               xenbus_frontend_closed(dev);
> +               break;
> +       }
> +}
> +
> +static struct xenbus_device_id xenkbd_ids[] = {
> +       { "vkbd" },
> +       { "" }
> +};
> +
> +static struct xenbus_driver xenkbd = {
> +       .name = "vkbd",
> +       .owner = THIS_MODULE,
> +       .ids = xenkbd_ids,
> +       .probe = xenkbd_probe,
> +       .remove = xenkbd_remove,
> +       .resume = xenkbd_resume,
> +       .otherend_changed = xenkbd_backend_changed,
> +};
> +
> +static int __init xenkbd_init(void)
> +{
> +       if (!is_running_on_xen())
> +               return -ENODEV;
> +
> +       /* Nothing to do if running in dom0. */
> +       if (is_initial_xendomain())
> +               return -ENODEV;
> +
> +       return xenbus_register_frontend(&xenkbd);
> +}
> +
> +static void __exit xenkbd_cleanup(void)
> +{
> +       xenbus_unregister_driver(&xenkbd);
> +}
> +
> +module_init(xenkbd_init);
> +module_exit(xenkbd_cleanup);
> +
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> index 758435f..67de177 100644
> --- a/drivers/video/Kconfig
> +++ b/drivers/video/Kconfig
> @@ -1903,6 +1903,20 @@ config FB_VIRTUAL
>  
>  	  If unsure, say N.
>  
> +config XEN_FBDEV_FRONTEND
> +       tristate "Xen virtual frame buffer support"
> +       depends on FB && XEN
> +       select FB_SYS_FILLRECT
> +       select FB_SYS_COPYAREA
> +       select FB_SYS_IMAGEBLIT
> +       select FB_SYS_FOPS
> +       select FB_DEFERRED_IO
> +       default y
> +       help
> +         This driver implements the front-end of the Xen virtual
> +         frame buffer driver.  It communicates with a back-end
> +         in another domain.
> +
>  source "drivers/video/omap/Kconfig"
>  
>  source "drivers/video/backlight/Kconfig"
> diff --git a/drivers/video/Makefile b/drivers/video/Makefile
> index 83e02b3..d3ab9b2 100644
> --- a/drivers/video/Makefile
> +++ b/drivers/video/Makefile
> @@ -113,6 +113,7 @@ obj-$(CONFIG_FB_PS3)                  += ps3fb.o
>  obj-$(CONFIG_FB_SM501)            += sm501fb.o
>  obj-$(CONFIG_FB_XILINX)           += xilinxfb.o
>  obj-$(CONFIG_FB_OMAP)             += omap/
> +obj-$(CONFIG_XEN_FBDEV_FRONTEND)  += xen-fbfront.o
>  
>  # Platform or fallback drivers go here
>  obj-$(CONFIG_FB_UVESA)            += uvesafb.o
> diff --git a/drivers/video/xen-fbfront.c b/drivers/video/xen-fbfront.c
> new file mode 100644
> index 0000000..bf8f900
> --- /dev/null
> +++ b/drivers/video/xen-fbfront.c
> @@ -0,0 +1,550 @@
> +/*
> + * Xen para-virtual frame buffer device
> + *
> + * Copyright (C) 2005-2006 Anthony Liguori <aliguori@xxxxxxxxxx>
> + * Copyright (C) 2006-2008 Red Hat, Inc., Markus Armbruster <armbru@xxxxxxxxxx>
> + *
> + *  Based on linux/drivers/video/q40fb.c
> + *
> + *  This file is subject to the terms and conditions of the GNU General Public
> + *  License. See the file COPYING in the main directory of this archive for
> + *  more details.
> + */
> +
> +/*
> + * TODO:
> + *
> + * Switch to grant tables when they become capable of dealing with the
> + * frame buffer.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/errno.h>
> +#include <linux/fb.h>
> +#include <linux/module.h>
> +#include <linux/vmalloc.h>
> +#include <linux/mm.h>
> +#include <asm/xen/hypervisor.h>
> +#include <xen/events.h>
> +#include <xen/page.h>
> +#include <xen/interface/io/fbif.h>
> +#include <xen/interface/io/protocols.h>
> +#include <xen/xenbus.h>
> +
> +struct xenfb_info {
> +       unsigned char           *fb;
> +       struct fb_info          *fb_info;
> +       int                     x1, y1, x2, y2; /* dirty rectangle,
> +                                                  protected by dirty_lock */
> +       spinlock_t              dirty_lock;
> +       int                     nr_pages;
> +       int                     evtchn, irq;
> +       struct xenfb_page       *page;
> +       unsigned long           *mfns;
> +       int                     update_wanted; /* XENFB_TYPE_UPDATE wanted */
> +
> +       struct xenbus_device    *xbdev;
> +};
> +
> +static u32 xenfb_mem_len = XENFB_WIDTH * XENFB_HEIGHT * XENFB_DEPTH / 8;
> +
> +static int xenfb_remove(struct xenbus_device *);
> +static void xenfb_init_shared_page(struct xenfb_info *);
> +static int xenfb_connect_backend(struct xenbus_device *, struct xenfb_info *);
> +static void xenfb_disconnect_backend(struct xenfb_info *);
> +
> +static void xenfb_do_update(struct xenfb_info *info,
> +                           int x, int y, int w, int h)
> +{
> +       union xenfb_out_event event;
> +       u32 prod;
> +
> +       event.type = XENFB_TYPE_UPDATE;
> +       event.update.x = x;
> +       event.update.y = y;
> +       event.update.width = w;
> +       event.update.height = h;
> +
> +       prod = info->page->out_prod;
> +       /* caller ensures !xenfb_queue_full() */
> +       mb();                   /* ensure ring space available */
> +       XENFB_OUT_RING_REF(info->page, prod) = event;
> +       wmb();                  /* ensure ring contents visible */
> +       info->page->out_prod = prod + 1;
> +
> +       notify_remote_via_irq(info->irq);
> +}
> +
> +static int xenfb_queue_full(struct xenfb_info *info)
> +{
> +       u32 cons, prod;
> +
> +       prod = info->page->out_prod;
> +       cons = info->page->out_cons;
> +       return prod - cons == XENFB_OUT_RING_LEN;
> +}
> +
> +static void xenfb_refresh(struct xenfb_info *info,
> +                         int x1, int y1, int w, int h)
> +{
> +       unsigned long flags;
> +       int y2 = y1 + h - 1;
> +       int x2 = x1 + w - 1;
> +
> +       if (!info->update_wanted)
> +               return;
> +
> +       spin_lock_irqsave(&info->dirty_lock, flags);
> +
> +       /* Combine with dirty rectangle: */
> +       if (info->y1 < y1)
> +               y1 = info->y1;
> +       if (info->y2 > y2)
> +               y2 = info->y2;
> +       if (info->x1 < x1)
> +               x1 = info->x1;
> +       if (info->x2 > x2)
> +               x2 = info->x2;
> +
> +       if (xenfb_queue_full(info)) {
> +               /* Can't send right now, stash it in the dirty rectangle */
> +               info->x1 = x1;
> +               info->x2 = x2;
> +               info->y1 = y1;
> +               info->y2 = y2;
> +               spin_unlock_irqrestore(&info->dirty_lock, flags);
> +               return;
> +       }
> +
> +       /* Clear dirty rectangle: */
> +       info->x1 = info->y1 = INT_MAX;
> +       info->x2 = info->y2 = 0;
> +
> +       spin_unlock_irqrestore(&info->dirty_lock, flags);
> +
> +       if (x1 <= x2 && y1 <= y2)
> +               xenfb_do_update(info, x1, y1, x2 - x1 + 1, y2 - y1 + 1);
> +}
> +
> +static void xenfb_deferred_io(struct fb_info *fb_info,
> +                             struct list_head *pagelist)
> +{
> +       struct xenfb_info *info = fb_info->par;
> +       struct page *page;
> +       unsigned long beg, end;
> +       int y1, y2, miny, maxy;
> +
> +       miny = INT_MAX;
> +       maxy = 0;
> +       list_for_each_entry(page, pagelist, lru) {
> +               beg = page->index << PAGE_SHIFT;
> +               end = beg + PAGE_SIZE - 1;
> +               y1 = beg / fb_info->fix.line_length;
> +               y2 = end / fb_info->fix.line_length;
> +               if (y2 >= fb_info->var.yres)
> +                       y2 = fb_info->var.yres - 1;
> +               if (miny > y1)
> +                       miny = y1;
> +               if (maxy < y2)
> +                       maxy = y2;
> +       }
> +       xenfb_refresh(info, 0, miny, fb_info->var.xres, maxy - miny + 1);
> +}
> +
> +static struct fb_deferred_io xenfb_defio = {
> +       .delay          = HZ / 20,
> +       .deferred_io    = xenfb_deferred_io,
> +};
> +
> +static int xenfb_setcolreg(unsigned regno, unsigned red, unsigned green,
> +                          unsigned blue, unsigned transp,
> +                          struct fb_info *info)
> +{
> +       u32 v;
> +
> +       if (regno > info->cmap.len)
> +               return 1;
> +
> +#define CNVT_TOHW(val, width) ((((val)<<(width))+0x7FFF-(val))>>16)
> +       red = CNVT_TOHW(red, info->var.red.length);
> +       green = CNVT_TOHW(green, info->var.green.length);
> +       blue = CNVT_TOHW(blue, info->var.blue.length);
> +       transp = CNVT_TOHW(transp, info->var.transp.length);
> +#undef CNVT_TOHW
> +
> +       v = (red << info->var.red.offset) |
> +           (green << info->var.green.offset) |
> +           (blue << info->var.blue.offset);
> +
> +       switch (info->var.bits_per_pixel) {
> +       case 16:
> +       case 24:
> +       case 32:
> +               ((u32 *)info->pseudo_palette)[regno] = v;
> +               break;
> +       }
> +
> +       return 0;
> +}
> +
> +static void xenfb_fillrect(struct fb_info *p, const struct fb_fillrect *rect)
> +{
> +       struct xenfb_info *info = p->par;
> +
> +       sys_fillrect(p, rect);
> +       xenfb_refresh(info, rect->dx, rect->dy, rect->width, rect->height);
> +}
> +
> +static void xenfb_imageblit(struct fb_info *p, const struct fb_image *image)
> +{
> +       struct xenfb_info *info = p->par;
> +
> +       sys_imageblit(p, image);
> +       xenfb_refresh(info, image->dx, image->dy, image->width, image->height);
> +}
> +
> +static void xenfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
> +{
> +       struct xenfb_info *info = p->par;
> +
> +       sys_copyarea(p, area);
> +       xenfb_refresh(info, area->dx, area->dy, area->width, area->height);
> +}
> +
> +static ssize_t xenfb_write(struct fb_info *p, const char __user *buf,
> +                       size_t count, loff_t *ppos)
> +{
> +       struct xenfb_info *info = p->par;
> +       ssize_t res;
> +
> +       res = fb_sys_write(p, buf, count, ppos);
> +       xenfb_refresh(info, 0, 0, info->page->width, info->page->height);
> +       return res;
> +}
> +
> +static struct fb_ops xenfb_fb_ops = {
> +       .owner          = THIS_MODULE,
> +       .fb_read        = fb_sys_read,
> +       .fb_write       = xenfb_write,
> +       .fb_setcolreg   = xenfb_setcolreg,
> +       .fb_fillrect    = xenfb_fillrect,
> +       .fb_copyarea    = xenfb_copyarea,
> +       .fb_imageblit   = xenfb_imageblit,
> +};
> +
> +static irqreturn_t xenfb_event_handler(int rq, void *dev_id)
> +{
> +       /*
> +        * No in events recognized, simply ignore them all.
> +        * If you need to recognize some, see xen-kbdfront's
> +        * input_handler() for how to do that.
> +        */
> +       struct xenfb_info *info = dev_id;
> +       struct xenfb_page *page = info->page;
> +
> +       if (page->in_cons != page->in_prod) {
> +               info->page->in_cons = info->page->in_prod;
> +               notify_remote_via_irq(info->irq);
> +       }
> +
> +       /* Flush dirty rectangle: */
> +       xenfb_refresh(info, INT_MAX, INT_MAX, -INT_MAX, -INT_MAX);
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static int __devinit xenfb_probe(struct xenbus_device *dev,
> +                                const struct xenbus_device_id *id)
> +{
> +       struct xenfb_info *info;
> +       struct fb_info *fb_info;
> +       int ret;
> +
> +       info = kzalloc(sizeof(*info), GFP_KERNEL);
> +       if (info == NULL) {
> +               xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
> +               return -ENOMEM;
> +       }
> +       dev->dev.driver_data = info;
> +       info->xbdev = dev;
> +       info->irq = -1;
> +       info->x1 = info->y1 = INT_MAX;
> +       spin_lock_init(&info->dirty_lock);
> +
> +       info->fb = vmalloc(xenfb_mem_len);
> +       if (info->fb == NULL)
> +               goto error_nomem;
> +       memset(info->fb, 0, xenfb_mem_len);
> +
> +       info->nr_pages = (xenfb_mem_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
> +
> +       info->mfns = vmalloc(sizeof(unsigned long) * info->nr_pages);
> +       if (!info->mfns)
> +               goto error_nomem;
> +
> +       /* set up shared page */
> +       info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
> +       if (!info->page)
> +               goto error_nomem;
> +
> +       xenfb_init_shared_page(info);
> +
> +       /* abusing framebuffer_alloc() to allocate pseudo_palette */
> +       fb_info = framebuffer_alloc(sizeof(u32) * 256, NULL);
> +       if (fb_info == NULL)
> +               goto error_nomem;
> +
> +       /* complete the abuse: */
> +       fb_info->pseudo_palette = fb_info->par;
> +       fb_info->par = info;
> +
> +       fb_info->screen_base = info->fb;
> +
> +       fb_info->fbops = &xenfb_fb_ops;
> +       fb_info->var.xres_virtual = fb_info->var.xres = info->page->width;
> +       fb_info->var.yres_virtual = fb_info->var.yres = info->page->height;
> +       fb_info->var.bits_per_pixel = info->page->depth;
> +
> +       fb_info->var.red = (struct fb_bitfield){16, 8, 0};
> +       fb_info->var.green = (struct fb_bitfield){8, 8, 0};
> +       fb_info->var.blue = (struct fb_bitfield){0, 8, 0};
> +
> +       fb_info->var.activate = FB_ACTIVATE_NOW;
> +       fb_info->var.height = -1;
> +       fb_info->var.width = -1;
> +       fb_info->var.vmode = FB_VMODE_NONINTERLACED;
> +
> +       fb_info->fix.visual = FB_VISUAL_TRUECOLOR;
> +       fb_info->fix.line_length = info->page->line_length;
> +       fb_info->fix.smem_start = 0;
> +       fb_info->fix.smem_len = xenfb_mem_len;
> +       strcpy(fb_info->fix.id, "xen");
> +       fb_info->fix.type = FB_TYPE_PACKED_PIXELS;
> +       fb_info->fix.accel = FB_ACCEL_NONE;
> +
> +       fb_info->flags = FBINFO_FLAG_DEFAULT;
> +
> +       ret = fb_alloc_cmap(&fb_info->cmap, 256, 0);
> +       if (ret < 0) {
> +               framebuffer_release(fb_info);
> +               xenbus_dev_fatal(dev, ret, "fb_alloc_cmap");
> +               goto error;
> +       }
> +
> +       fb_info->fbdefio = &xenfb_defio;
> +       fb_deferred_io_init(fb_info);
> +
> +       ret = register_framebuffer(fb_info);
> +       if (ret) {
> +               fb_dealloc_cmap(&fb_info->cmap);
> +               fb_deferred_io_cleanup(fb_info);
> +               framebuffer_release(fb_info);
> +               xenbus_dev_fatal(dev, ret, "register_framebuffer");
> +               goto error;
> +       }
> +       info->fb_info = fb_info;
> +
> +       ret = xenfb_connect_backend(dev, info);
> +       if (ret < 0)
> +               goto error;
> +
> +       return 0;
> +
> + error_nomem:
> +       ret = -ENOMEM;
> +       xenbus_dev_fatal(dev, ret, "allocating device memory");
> + error:
> +       xenfb_remove(dev);
> +       return ret;
> +}
> +
> +static int xenfb_resume(struct xenbus_device *dev)
> +{
> +       struct xenfb_info *info = dev->dev.driver_data;
> +
> +       xenfb_disconnect_backend(info);
> +       xenfb_init_shared_page(info);
> +       return xenfb_connect_backend(dev, info);
> +}
> +
> +static int xenfb_remove(struct xenbus_device *dev)
> +{
> +       struct xenfb_info *info = dev->dev.driver_data;
> +
> +       xenfb_disconnect_backend(info);
> +       if (info->fb_info) {
> +               fb_deferred_io_cleanup(info->fb_info);
> +               unregister_framebuffer(info->fb_info);
> +               fb_dealloc_cmap(&info->fb_info->cmap);
> +               framebuffer_release(info->fb_info);
> +       }
> +       free_page((unsigned long)info->page);
> +       vfree(info->mfns);
> +       vfree(info->fb);
> +       kfree(info);
> +
> +       return 0;
> +}
> +
> +static unsigned long vmalloc_to_mfn(void *address)
> +{
> +       return pfn_to_mfn(vmalloc_to_pfn(address));
> +}
> +
> +static void xenfb_init_shared_page(struct xenfb_info *info)
> +{
> +       int i;
> +
> +       for (i = 0; i < info->nr_pages; i++)
> +               info->mfns[i] = vmalloc_to_mfn(info->fb + i * PAGE_SIZE);
> +
> +       info->page->pd[0] = vmalloc_to_mfn(info->mfns);
> +       info->page->pd[1] = 0;
> +       info->page->width = XENFB_WIDTH;
> +       info->page->height = XENFB_HEIGHT;
> +       info->page->depth = XENFB_DEPTH;
> +       info->page->line_length = (info->page->depth / 8) * info->page->width;
> +       info->page->mem_length = xenfb_mem_len;
> +       info->page->in_cons = info->page->in_prod = 0;
> +       info->page->out_cons = info->page->out_prod = 0;
> +}
> +
> +static int xenfb_connect_backend(struct xenbus_device *dev,
> +                                struct xenfb_info *info)
> +{
> +       int ret;
> +       struct xenbus_transaction xbt;
> +
> +       ret = xenbus_alloc_evtchn(dev, &info->evtchn);
> +       if (ret)
> +               return ret;
> +       ret = bind_evtchn_to_irqhandler(info->evtchn, xenfb_event_handler,
> +                                       0, dev->devicetype, info);
> +       if (ret < 0) {
> +               xenbus_free_evtchn(dev, info->evtchn);
> +               xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
> +               return ret;
> +       }
> +       info->irq = ret;
> +
> + again:
> +       ret = xenbus_transaction_start(&xbt);
> +       if (ret) {
> +               xenbus_dev_fatal(dev, ret, "starting transaction");
> +               return ret;
> +       }
> +       ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
> +                           virt_to_mfn(info->page));
> +       if (ret)
> +               goto error_xenbus;
> +       ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
> +                           info->evtchn);
> +       if (ret)
> +               goto error_xenbus;
> +       ret = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
> +                           XEN_IO_PROTO_ABI_NATIVE);
> +       if (ret)
> +               goto error_xenbus;
> +       ret = xenbus_printf(xbt, dev->nodename, "feature-update", "1");
> +       if (ret)
> +               goto error_xenbus;
> +       ret = xenbus_transaction_end(xbt, 0);
> +       if (ret) {
> +               if (ret == -EAGAIN)
> +                       goto again;
> +               xenbus_dev_fatal(dev, ret, "completing transaction");
> +               return ret;
> +       }
> +
> +       xenbus_switch_state(dev, XenbusStateInitialised);
> +       return 0;
> +
> + error_xenbus:
> +       xenbus_transaction_end(xbt, 1);
> +       xenbus_dev_fatal(dev, ret, "writing xenstore");
> +       return ret;
> +}
> +
> +static void xenfb_disconnect_backend(struct xenfb_info *info)
> +{
> +       if (info->irq >= 0)
> +               unbind_from_irqhandler(info->irq, info);
> +       info->irq = -1;
> +}
> +
> +static void xenfb_backend_changed(struct xenbus_device *dev,
> +                                 enum xenbus_state backend_state)
> +{
> +       struct xenfb_info *info = dev->dev.driver_data;
> +       int val;
> +
> +       switch (backend_state) {
> +       case XenbusStateInitialising:
> +       case XenbusStateInitialised:
> +       case XenbusStateUnknown:
> +       case XenbusStateClosed:
> +               break;
> +
> +       case XenbusStateInitWait:
> +InitWait:
> +               xenbus_switch_state(dev, XenbusStateConnected);
> +               break;
> +
> +       case XenbusStateConnected:
> +               /*
> +                * Work around xenbus race condition: If backend goes
> +                * through InitWait to Connected fast enough, we can
> +                * get Connected twice here.
> +                */
> +               if (dev->state != XenbusStateConnected)
> +                       goto InitWait; /* no InitWait seen yet, fudge it */
> +
> +               if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
> +                                "request-update", "%d", &val) < 0)
> +                       val = 0;
> +               if (val)
> +                       info->update_wanted = 1;
> +               break;
> +
> +       case XenbusStateClosing:
> +               xenbus_frontend_closed(dev);
> +               break;
> +       }
> +}
> +
> +static struct xenbus_device_id xenfb_ids[] = {
> +       { "vfb" },
> +       { "" }
> +};
> +
> +static struct xenbus_driver xenfb = {
> +       .name = "vfb",
> +       .owner = THIS_MODULE,
> +       .ids = xenfb_ids,
> +       .probe = xenfb_probe,
> +       .remove = xenfb_remove,
> +       .resume = xenfb_resume,
> +       .otherend_changed = xenfb_backend_changed,
> +};
> +
> +static int __init xenfb_init(void)
> +{
> +       if (!is_running_on_xen())
> +               return -ENODEV;
> +
> +       /* Nothing to do if running in dom0. */
> +       if (is_initial_xendomain())
> +               return -ENODEV;
> +
> +       return xenbus_register_frontend(&xenfb);
> +}
> +
> +static void __exit xenfb_cleanup(void)
> +{
> +       xenbus_unregister_driver(&xenfb);
> +}
> +
> +module_init(xenfb_init);
> +module_exit(xenfb_cleanup);
> +
> +MODULE_LICENSE("GPL");
> diff --git a/include/xen/interface/io/fbif.h b/include/xen/interface/io/fbif.h
> new file mode 100644
> index 0000000..5a934dd
> --- /dev/null
> +++ b/include/xen/interface/io/fbif.h
> @@ -0,0 +1,124 @@
> +/*
> + * fbif.h -- Xen virtual frame buffer device
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to
> + * deal in the Software without restriction, including without limitation the
> + * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
> + * sell copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
> + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> + * DEALINGS IN THE SOFTWARE.
> + *
> + * Copyright (C) 2005 Anthony Liguori <aliguori@xxxxxxxxxx>
> + * Copyright (C) 2006 Red Hat, Inc., Markus Armbruster <armbru@xxxxxxxxxx>
> + */
> +
> +#ifndef __XEN_PUBLIC_IO_FBIF_H__
> +#define __XEN_PUBLIC_IO_FBIF_H__
> +
> +/* Out events (frontend -> backend) */
> +
> +/*
> + * Out events may be sent only when requested by backend, and receipt
> + * of an unknown out event is an error.
> + */
> +
> +/* Event type 1 currently not used */
> +/*
> + * Framebuffer update notification event
> + * Capable frontend sets feature-update in xenstore.
> + * Backend requests it by setting request-update in xenstore.
> + */
> +#define XENFB_TYPE_UPDATE 2
> +
> +struct xenfb_update {
> +       uint8_t type;           /* XENFB_TYPE_UPDATE */
> +       int32_t x;              /* source x */
> +       int32_t y;              /* source y */
> +       int32_t width;          /* rect width */
> +       int32_t height;         /* rect height */
> +};
> +
> +#define XENFB_OUT_EVENT_SIZE 40
> +
> +union xenfb_out_event {
> +       uint8_t type;
> +       struct xenfb_update update;
> +       char pad[XENFB_OUT_EVENT_SIZE];
> +};
> +
> +/* In events (backend -> frontend) */
> +
> +/*
> + * Frontends should ignore unknown in events.
> + * No in events currently defined.
> + */
> +
> +#define XENFB_IN_EVENT_SIZE 40
> +
> +union xenfb_in_event {
> +       uint8_t type;
> +       char pad[XENFB_IN_EVENT_SIZE];
> +};
> +
> +/* shared page */
> +
> +#define XENFB_IN_RING_SIZE 1024
> +#define XENFB_IN_RING_LEN (XENFB_IN_RING_SIZE / XENFB_IN_EVENT_SIZE)
> +#define XENFB_IN_RING_OFFS 1024
> +#define XENFB_IN_RING(page) \
> +       ((union xenfb_in_event *)((char *)(page) + XENFB_IN_RING_OFFS))
> +#define XENFB_IN_RING_REF(page, idx) \
> +       (XENFB_IN_RING((page))[(idx) % XENFB_IN_RING_LEN])
> +
> +#define XENFB_OUT_RING_SIZE 2048
> +#define XENFB_OUT_RING_LEN (XENFB_OUT_RING_SIZE / XENFB_OUT_EVENT_SIZE)
> +#define XENFB_OUT_RING_OFFS (XENFB_IN_RING_OFFS + XENFB_IN_RING_SIZE)
> +#define XENFB_OUT_RING(page) \
> +       ((union xenfb_out_event *)((char *)(page) + XENFB_OUT_RING_OFFS))
> +#define XENFB_OUT_RING_REF(page, idx) \
> +       (XENFB_OUT_RING((page))[(idx) % XENFB_OUT_RING_LEN])
> +
> +struct xenfb_page {
> +       uint32_t in_cons, in_prod;
> +       uint32_t out_cons, out_prod;
> +
> +       int32_t width;          /* width of the framebuffer (in pixels) */
> +       int32_t height;         /* height of the framebuffer (in pixels) */
> +       uint32_t line_length;   /* length of a row of pixels (in bytes) */
> +       uint32_t mem_length;    /* length of the framebuffer (in bytes) */
> +       uint8_t depth;          /* depth of a pixel (in bits) */
> +
> +       /*
> +        * Framebuffer page directory
> +        *
> +        * Each directory page holds PAGE_SIZE / sizeof(*pd)
> +        * framebuffer pages, and can thus map up to PAGE_SIZE *
> +        * PAGE_SIZE / sizeof(*pd) bytes.  With PAGE_SIZE == 4096 and
> +        * sizeof(unsigned long) == 4, that's 4 Megs.  Two directory
> +        * pages should be enough for a while.
> +        */
> +       unsigned long pd[2];
> +};
> +
> +/*
> + * Wart: xenkbd needs to know resolution.  Put it here until a better
> + * solution is found, but don't leak it to the backend.
> + */
> +#ifdef __KERNEL__
> +#define XENFB_WIDTH 800
> +#define XENFB_HEIGHT 600
> +#define XENFB_DEPTH 32
> +#endif
> +
> +#endif
> diff --git a/include/xen/interface/io/kbdif.h b/include/xen/interface/io/kbdif.h
> new file mode 100644
> index 0000000..fb97f42
> --- /dev/null
> +++ b/include/xen/interface/io/kbdif.h
> @@ -0,0 +1,114 @@
> +/*
> + * kbdif.h -- Xen virtual keyboard/mouse
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to
> + * deal in the Software without restriction, including without limitation the
> + * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
> + * sell copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
> + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> + * DEALINGS IN THE SOFTWARE.
> + *
> + * Copyright (C) 2005 Anthony Liguori <aliguori@xxxxxxxxxx>
> + * Copyright (C) 2006 Red Hat, Inc., Markus Armbruster <armbru@xxxxxxxxxx>
> + */
> +
> +#ifndef __XEN_PUBLIC_IO_KBDIF_H__
> +#define __XEN_PUBLIC_IO_KBDIF_H__
> +
> +/* In events (backend -> frontend) */
> +
> +/*
> + * Frontends should ignore unknown in events.
> + */
> +
> +/* Pointer movement event */
> +#define XENKBD_TYPE_MOTION  1
> +/* Event type 2 currently not used */
> +/* Key event (includes pointer buttons) */
> +#define XENKBD_TYPE_KEY     3
> +/*
> + * Pointer position event
> + * Capable backend sets feature-abs-pointer in xenstore.
> + * Frontend requests ot instead of XENKBD_TYPE_MOTION by setting
> + * request-abs-update in xenstore.
> + */
> +#define XENKBD_TYPE_POS     4
> +
> +struct xenkbd_motion {
> +       uint8_t type;           /* XENKBD_TYPE_MOTION */
> +       int32_t rel_x;          /* relative X motion */
> +       int32_t rel_y;          /* relative Y motion */
> +};
> +
> +struct xenkbd_key {
> +       uint8_t type;           /* XENKBD_TYPE_KEY */
> +       uint8_t pressed;        /* 1 if pressed; 0 otherwise */
> +       uint32_t keycode;       /* KEY_* from linux/input.h */
> +};
> +
> +struct xenkbd_position {
> +       uint8_t type;           /* XENKBD_TYPE_POS */
> +       int32_t abs_x;          /* absolute X position (in FB pixels) */
> +       int32_t abs_y;          /* absolute Y position (in FB pixels) */
> +};
> +
> +#define XENKBD_IN_EVENT_SIZE 40
> +
> +union xenkbd_in_event {
> +       uint8_t type;
> +       struct xenkbd_motion motion;
> +       struct xenkbd_key key;
> +       struct xenkbd_position pos;
> +       char pad[XENKBD_IN_EVENT_SIZE];
> +};
> +
> +/* Out events (frontend -> backend) */
> +
> +/*
> + * Out events may be sent only when requested by backend, and receipt
> + * of an unknown out event is an error.
> + * No out events currently defined.
> + */
> +
> +#define XENKBD_OUT_EVENT_SIZE 40
> +
> +union xenkbd_out_event {
> +       uint8_t type;
> +       char pad[XENKBD_OUT_EVENT_SIZE];
> +};
> +
> +/* shared page */
> +
> +#define XENKBD_IN_RING_SIZE 2048
> +#define XENKBD_IN_RING_LEN (XENKBD_IN_RING_SIZE / XENKBD_IN_EVENT_SIZE)
> +#define XENKBD_IN_RING_OFFS 1024
> +#define XENKBD_IN_RING(page) \
> +       ((union xenkbd_in_event *)((char *)(page) + XENKBD_IN_RING_OFFS))
> +#define XENKBD_IN_RING_REF(page, idx) \
> +       (XENKBD_IN_RING((page))[(idx) % XENKBD_IN_RING_LEN])
> +
> +#define XENKBD_OUT_RING_SIZE 1024
> +#define XENKBD_OUT_RING_LEN (XENKBD_OUT_RING_SIZE / XENKBD_OUT_EVENT_SIZE)
> +#define XENKBD_OUT_RING_OFFS (XENKBD_IN_RING_OFFS + XENKBD_IN_RING_SIZE)
> +#define XENKBD_OUT_RING(page) \
> +       ((union xenkbd_out_event *)((char *)(page) + XENKBD_OUT_RING_OFFS))
> +#define XENKBD_OUT_RING_REF(page, idx) \
> +       (XENKBD_OUT_RING((page))[(idx) % XENKBD_OUT_RING_LEN])
> +
> +struct xenkbd_page {
> +       uint32_t in_cons, in_prod;
> +       uint32_t out_cons, out_prod;
> +};
> +
> +#endif
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>   
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