xen-fbfront.c

  1/*
  2 * Xen para-virtual frame buffer device
  3 *
  4 * Copyright (C) 2005-2006 Anthony Liguori <aliguori@us.ibm.com>
  5 * Copyright (C) 2006-2008 Red Hat, Inc., Markus Armbruster <armbru@redhat.com>
  6 *
  7 *  Based on linux/drivers/video/q40fb.c
  8 *
  9 *  This file is subject to the terms and conditions of the GNU General Public
 10 *  License. See the file COPYING in the main directory of this archive for
 11 *  more details.
 12 */
 13
 14/*
 15 * TODO:
 16 *
 17 * Switch to grant tables when they become capable of dealing with the
 18 * frame buffer.
 19 */
 20
 21#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 22
 23#include <linux/console.h>
 24#include <linux/kernel.h>
 25#include <linux/errno.h>
 26#include <linux/fb.h>
 27#include <linux/module.h>
 28#include <linux/slab.h>
 29#include <linux/vmalloc.h>
 30#include <linux/mm.h>
 31
 32#include <asm/xen/hypervisor.h>
 33
 34#include <xen/xen.h>
 35#include <xen/events.h>
 36#include <xen/page.h>
 37#include <xen/interface/io/fbif.h>
 38#include <xen/interface/io/protocols.h>
 39#include <xen/xenbus.h>
 40#include <xen/platform_pci.h>
 41
 42struct xenfb_info {
 43	unsigned char		*fb;
 44	struct fb_info		*fb_info;
 45	int			x1, y1, x2, y2;	/* dirty rectangle,
 46						   protected by dirty_lock */
 47	spinlock_t		dirty_lock;
 48	int			nr_pages;
 49	int			irq;
 50	struct xenfb_page	*page;
 51	unsigned long 		*gfns;
 52	int			update_wanted; /* XENFB_TYPE_UPDATE wanted */
 53	int			feature_resize; /* XENFB_TYPE_RESIZE ok */
 54	struct xenfb_resize	resize;		/* protected by resize_lock */
 55	int			resize_dpy;	/* ditto */
 56	spinlock_t		resize_lock;
 57
 58	struct xenbus_device	*xbdev;
 59};
 60
 61#define XENFB_DEFAULT_FB_LEN (XENFB_WIDTH * XENFB_HEIGHT * XENFB_DEPTH / 8)
 62
 63enum { KPARAM_MEM, KPARAM_WIDTH, KPARAM_HEIGHT, KPARAM_CNT };
 64static int video[KPARAM_CNT] = { 2, XENFB_WIDTH, XENFB_HEIGHT };
 65module_param_array(video, int, NULL, 0);
 66MODULE_PARM_DESC(video,
 67	"Video memory size in MB, width, height in pixels (default 2,800,600)");
 68
 69static void xenfb_make_preferred_console(void);
 70static void xenfb_remove(struct xenbus_device *);
 71static void xenfb_init_shared_page(struct xenfb_info *, struct fb_info *);
 72static int xenfb_connect_backend(struct xenbus_device *, struct xenfb_info *);
 73static void xenfb_disconnect_backend(struct xenfb_info *);
 74
 75static void xenfb_send_event(struct xenfb_info *info,
 76			     union xenfb_out_event *event)
 77{
 78	u32 prod;
 79
 80	prod = info->page->out_prod;
 81	/* caller ensures !xenfb_queue_full() */
 82	mb();			/* ensure ring space available */
 83	XENFB_OUT_RING_REF(info->page, prod) = *event;
 84	wmb();			/* ensure ring contents visible */
 85	info->page->out_prod = prod + 1;
 86
 87	notify_remote_via_irq(info->irq);
 88}
 89
 90static void xenfb_do_update(struct xenfb_info *info,
 91			    int x, int y, int w, int h)
 92{
 93	union xenfb_out_event event;
 94
 95	memset(&event, 0, sizeof(event));
 96	event.type = XENFB_TYPE_UPDATE;
 97	event.update.x = x;
 98	event.update.y = y;
 99	event.update.width = w;
100	event.update.height = h;
101
102	/* caller ensures !xenfb_queue_full() */
103	xenfb_send_event(info, &event);
104}
105
106static void xenfb_do_resize(struct xenfb_info *info)
107{
108	union xenfb_out_event event;
109
110	memset(&event, 0, sizeof(event));
111	event.resize = info->resize;
112
113	/* caller ensures !xenfb_queue_full() */
114	xenfb_send_event(info, &event);
115}
116
117static int xenfb_queue_full(struct xenfb_info *info)
118{
119	u32 cons, prod;
120
121	prod = info->page->out_prod;
122	cons = info->page->out_cons;
123	return prod - cons == XENFB_OUT_RING_LEN;
124}
125
126static void xenfb_handle_resize_dpy(struct xenfb_info *info)
127{
128	unsigned long flags;
129
130	spin_lock_irqsave(&info->resize_lock, flags);
131	if (info->resize_dpy) {
132		if (!xenfb_queue_full(info)) {
133			info->resize_dpy = 0;
134			xenfb_do_resize(info);
135		}
136	}
137	spin_unlock_irqrestore(&info->resize_lock, flags);
138}
139
140static void xenfb_refresh(struct xenfb_info *info,
141			  int x1, int y1, int w, int h)
142{
143	unsigned long flags;
144	int x2 = x1 + w - 1;
145	int y2 = y1 + h - 1;
146
147	xenfb_handle_resize_dpy(info);
148
149	if (!info->update_wanted)
150		return;
151
152	spin_lock_irqsave(&info->dirty_lock, flags);
153
154	/* Combine with dirty rectangle: */
155	if (info->y1 < y1)
156		y1 = info->y1;
157	if (info->y2 > y2)
158		y2 = info->y2;
159	if (info->x1 < x1)
160		x1 = info->x1;
161	if (info->x2 > x2)
162		x2 = info->x2;
163
164	if (xenfb_queue_full(info)) {
165		/* Can't send right now, stash it in the dirty rectangle */
166		info->x1 = x1;
167		info->x2 = x2;
168		info->y1 = y1;
169		info->y2 = y2;
170		spin_unlock_irqrestore(&info->dirty_lock, flags);
171		return;
172	}
173
174	/* Clear dirty rectangle: */
175	info->x1 = info->y1 = INT_MAX;
176	info->x2 = info->y2 = 0;
177
178	spin_unlock_irqrestore(&info->dirty_lock, flags);
179
180	if (x1 <= x2 && y1 <= y2)
181		xenfb_do_update(info, x1, y1, x2 - x1 + 1, y2 - y1 + 1);
182}
183
184static void xenfb_deferred_io(struct fb_info *fb_info, struct list_head *pagereflist)
185{
186	struct xenfb_info *info = fb_info->par;
187	struct fb_deferred_io_pageref *pageref;
188	unsigned long beg, end;
189	int y1, y2, miny, maxy;
190
191	miny = INT_MAX;
192	maxy = 0;
193	list_for_each_entry(pageref, pagereflist, list) {
194		beg = pageref->offset;
195		end = beg + PAGE_SIZE - 1;
196		y1 = beg / fb_info->fix.line_length;
197		y2 = end / fb_info->fix.line_length;
198		if (y2 >= fb_info->var.yres)
199			y2 = fb_info->var.yres - 1;
200		if (miny > y1)
201			miny = y1;
202		if (maxy < y2)
203			maxy = y2;
204	}
205	xenfb_refresh(info, 0, miny, fb_info->var.xres, maxy - miny + 1);
206}
207
208static struct fb_deferred_io xenfb_defio = {
209	.delay		= HZ / 20,
210	.deferred_io	= xenfb_deferred_io,
211};
212
213static int xenfb_setcolreg(unsigned regno, unsigned red, unsigned green,
214			   unsigned blue, unsigned transp,
215			   struct fb_info *info)
216{
217	u32 v;
218
219	if (regno > info->cmap.len)
220		return 1;
221
222#define CNVT_TOHW(val, width) ((((val)<<(width))+0x7FFF-(val))>>16)
223	red = CNVT_TOHW(red, info->var.red.length);
224	green = CNVT_TOHW(green, info->var.green.length);
225	blue = CNVT_TOHW(blue, info->var.blue.length);
226#undef CNVT_TOHW
227
228	v = (red << info->var.red.offset) |
229	    (green << info->var.green.offset) |
230	    (blue << info->var.blue.offset);
231
232	switch (info->var.bits_per_pixel) {
233	case 16:
234	case 24:
235	case 32:
236		((u32 *)info->pseudo_palette)[regno] = v;
237		break;
238	}
239
240	return 0;
241}
242
243static int
244xenfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
245{
246	struct xenfb_info *xenfb_info;
247	int required_mem_len;
248
249	xenfb_info = info->par;
250
251	if (!xenfb_info->feature_resize) {
252		if (var->xres == video[KPARAM_WIDTH] &&
253		    var->yres == video[KPARAM_HEIGHT] &&
254		    var->bits_per_pixel == xenfb_info->page->depth) {
255			return 0;
256		}
257		return -EINVAL;
258	}
259
260	/* Can't resize past initial width and height */
261	if (var->xres > video[KPARAM_WIDTH] || var->yres > video[KPARAM_HEIGHT])
262		return -EINVAL;
263
264	required_mem_len = var->xres * var->yres * xenfb_info->page->depth / 8;
265	if (var->bits_per_pixel == xenfb_info->page->depth &&
266	    var->xres <= info->fix.line_length / (XENFB_DEPTH / 8) &&
267	    required_mem_len <= info->fix.smem_len) {
268		var->xres_virtual = var->xres;
269		var->yres_virtual = var->yres;
270		return 0;
271	}
272	return -EINVAL;
273}
274
275static int xenfb_set_par(struct fb_info *info)
276{
277	struct xenfb_info *xenfb_info;
278	unsigned long flags;
279
280	xenfb_info = info->par;
281
282	spin_lock_irqsave(&xenfb_info->resize_lock, flags);
283	xenfb_info->resize.type = XENFB_TYPE_RESIZE;
284	xenfb_info->resize.width = info->var.xres;
285	xenfb_info->resize.height = info->var.yres;
286	xenfb_info->resize.stride = info->fix.line_length;
287	xenfb_info->resize.depth = info->var.bits_per_pixel;
288	xenfb_info->resize.offset = 0;
289	xenfb_info->resize_dpy = 1;
290	spin_unlock_irqrestore(&xenfb_info->resize_lock, flags);
291	return 0;
292}
293
294static void xenfb_defio_damage_range(struct fb_info *info, off_t off, size_t len)
295{
296	struct xenfb_info *xenfb_info = info->par;
297
298	xenfb_refresh(xenfb_info, 0, 0, xenfb_info->page->width, xenfb_info->page->height);
299}
300
301static void xenfb_defio_damage_area(struct fb_info *info, u32 x, u32 y,
302				    u32 width, u32 height)
303{
304	struct xenfb_info *xenfb_info = info->par;
305
306	xenfb_refresh(xenfb_info, x, y, width, height);
307}
308
309FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(xenfb,
310				   xenfb_defio_damage_range,
311				   xenfb_defio_damage_area)
312
313static const struct fb_ops xenfb_fb_ops = {
314	.owner		= THIS_MODULE,
315	FB_DEFAULT_DEFERRED_OPS(xenfb),
316	.fb_setcolreg	= xenfb_setcolreg,
317	.fb_check_var	= xenfb_check_var,
318	.fb_set_par     = xenfb_set_par,
319};
320
321static irqreturn_t xenfb_event_handler(int rq, void *dev_id)
322{
323	/*
324	 * No in events recognized, simply ignore them all.
325	 * If you need to recognize some, see xen-kbdfront's
326	 * input_handler() for how to do that.
327	 */
328	struct xenfb_info *info = dev_id;
329	struct xenfb_page *page = info->page;
330
331	if (page->in_cons != page->in_prod) {
332		info->page->in_cons = info->page->in_prod;
333		notify_remote_via_irq(info->irq);
334	}
335
336	/* Flush dirty rectangle: */
337	xenfb_refresh(info, INT_MAX, INT_MAX, -INT_MAX, -INT_MAX);
338
339	return IRQ_HANDLED;
340}
341
342static int xenfb_probe(struct xenbus_device *dev,
343		       const struct xenbus_device_id *id)
344{
345	struct xenfb_info *info;
346	struct fb_info *fb_info;
347	int fb_size;
348	int val;
349	int ret = 0;
350
351	info = kzalloc(sizeof(*info), GFP_KERNEL);
352	if (info == NULL) {
353		xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
354		return -ENOMEM;
355	}
356
357	/* Limit kernel param videoram amount to what is in xenstore */
358	if (xenbus_scanf(XBT_NIL, dev->otherend, "videoram", "%d", &val) == 1) {
359		if (val < video[KPARAM_MEM])
360			video[KPARAM_MEM] = val;
361	}
362
363	video[KPARAM_WIDTH] = xenbus_read_unsigned(dev->otherend, "width",
364						   video[KPARAM_WIDTH]);
365	video[KPARAM_HEIGHT] = xenbus_read_unsigned(dev->otherend, "height",
366						    video[KPARAM_HEIGHT]);
367
368	/* If requested res does not fit in available memory, use default */
369	fb_size = video[KPARAM_MEM] * 1024 * 1024;
370	if (video[KPARAM_WIDTH] * video[KPARAM_HEIGHT] * XENFB_DEPTH / 8
371	    > fb_size) {
372		pr_warn("display parameters %d,%d,%d invalid, use defaults\n",
373			video[KPARAM_MEM], video[KPARAM_WIDTH],
374			video[KPARAM_HEIGHT]);
375		video[KPARAM_WIDTH] = XENFB_WIDTH;
376		video[KPARAM_HEIGHT] = XENFB_HEIGHT;
377		fb_size = XENFB_DEFAULT_FB_LEN;
378	}
379
380	dev_set_drvdata(&dev->dev, info);
381	info->xbdev = dev;
382	info->irq = -1;
383	info->x1 = info->y1 = INT_MAX;
384	spin_lock_init(&info->dirty_lock);
385	spin_lock_init(&info->resize_lock);
386
387	info->fb = vzalloc(fb_size);
388	if (info->fb == NULL)
389		goto error_nomem;
390
391	info->nr_pages = (fb_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
392
393	info->gfns = vmalloc_array(info->nr_pages, sizeof(unsigned long));
394	if (!info->gfns)
395		goto error_nomem;
396
397	/* set up shared page */
398	info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
399	if (!info->page)
400		goto error_nomem;
401
402	/* abusing framebuffer_alloc() to allocate pseudo_palette */
403	fb_info = framebuffer_alloc(sizeof(u32) * 256, NULL);
404	if (fb_info == NULL)
405		goto error_nomem;
406
407	/* complete the abuse: */
408	fb_info->pseudo_palette = fb_info->par;
409	fb_info->par = info;
410	fb_info->device = &dev->dev;
411
412	fb_info->screen_buffer = info->fb;
413
414	fb_info->fbops = &xenfb_fb_ops;
415	fb_info->var.xres_virtual = fb_info->var.xres = video[KPARAM_WIDTH];
416	fb_info->var.yres_virtual = fb_info->var.yres = video[KPARAM_HEIGHT];
417	fb_info->var.bits_per_pixel = XENFB_DEPTH;
418
419	fb_info->var.red = (struct fb_bitfield){16, 8, 0};
420	fb_info->var.green = (struct fb_bitfield){8, 8, 0};
421	fb_info->var.blue = (struct fb_bitfield){0, 8, 0};
422
423	fb_info->var.activate = FB_ACTIVATE_NOW;
424	fb_info->var.height = -1;
425	fb_info->var.width = -1;
426	fb_info->var.vmode = FB_VMODE_NONINTERLACED;
427
428	fb_info->fix.visual = FB_VISUAL_TRUECOLOR;
429	fb_info->fix.line_length = fb_info->var.xres * XENFB_DEPTH / 8;
430	fb_info->fix.smem_start = 0;
431	fb_info->fix.smem_len = fb_size;
432	strcpy(fb_info->fix.id, "xen");
433	fb_info->fix.type = FB_TYPE_PACKED_PIXELS;
434	fb_info->fix.accel = FB_ACCEL_NONE;
435
436	fb_info->flags = FBINFO_VIRTFB;
437
438	ret = fb_alloc_cmap(&fb_info->cmap, 256, 0);
439	if (ret < 0) {
440		framebuffer_release(fb_info);
441		xenbus_dev_fatal(dev, ret, "fb_alloc_cmap");
442		goto error;
443	}
444
445	fb_info->fbdefio = &xenfb_defio;
446	fb_deferred_io_init(fb_info);
447
448	xenfb_init_shared_page(info, fb_info);
449
450	ret = xenfb_connect_backend(dev, info);
451	if (ret < 0) {
452		xenbus_dev_fatal(dev, ret, "xenfb_connect_backend");
453		goto error_fb;
454	}
455
456	ret = register_framebuffer(fb_info);
457	if (ret) {
458		xenbus_dev_fatal(dev, ret, "register_framebuffer");
459		goto error_fb;
460	}
461	info->fb_info = fb_info;
462
463	xenfb_make_preferred_console();
464	return 0;
465
466error_fb:
467	fb_deferred_io_cleanup(fb_info);
468	fb_dealloc_cmap(&fb_info->cmap);
469	framebuffer_release(fb_info);
470error_nomem:
471	if (!ret) {
472		ret = -ENOMEM;
473		xenbus_dev_fatal(dev, ret, "allocating device memory");
474	}
475error:
476	xenfb_remove(dev);
477	return ret;
478}
479
480static void xenfb_make_preferred_console(void)
481{
482	struct console *c;
483
484	if (console_set_on_cmdline)
485		return;
486
487	console_list_lock();
488	for_each_console(c) {
489		if (!strcmp(c->name, "tty") && c->index == 0)
490			break;
491	}
492	if (c)
493		console_force_preferred_locked(c);
494	console_list_unlock();
495}
496
497static int xenfb_resume(struct xenbus_device *dev)
498{
499	struct xenfb_info *info = dev_get_drvdata(&dev->dev);
500
501	xenfb_disconnect_backend(info);
502	xenfb_init_shared_page(info, info->fb_info);
503	return xenfb_connect_backend(dev, info);
504}
505
506static void xenfb_remove(struct xenbus_device *dev)
507{
508	struct xenfb_info *info = dev_get_drvdata(&dev->dev);
509
510	xenfb_disconnect_backend(info);
511	if (info->fb_info) {
512		fb_deferred_io_cleanup(info->fb_info);
513		unregister_framebuffer(info->fb_info);
514		fb_dealloc_cmap(&info->fb_info->cmap);
515		framebuffer_release(info->fb_info);
516	}
517	free_page((unsigned long)info->page);
518	vfree(info->gfns);
519	vfree(info->fb);
520	kfree(info);
521}
522
523static unsigned long vmalloc_to_gfn(void *address)
524{
525	return xen_page_to_gfn(vmalloc_to_page(address));
526}
527
528static void xenfb_init_shared_page(struct xenfb_info *info,
529				   struct fb_info *fb_info)
530{
531	int i;
532	int epd = PAGE_SIZE / sizeof(info->gfns[0]);
533
534	for (i = 0; i < info->nr_pages; i++)
535		info->gfns[i] = vmalloc_to_gfn(info->fb + i * PAGE_SIZE);
536
537	for (i = 0; i * epd < info->nr_pages; i++)
538		info->page->pd[i] = vmalloc_to_gfn(&info->gfns[i * epd]);
539
540	info->page->width = fb_info->var.xres;
541	info->page->height = fb_info->var.yres;
542	info->page->depth = fb_info->var.bits_per_pixel;
543	info->page->line_length = fb_info->fix.line_length;
544	info->page->mem_length = fb_info->fix.smem_len;
545	info->page->in_cons = info->page->in_prod = 0;
546	info->page->out_cons = info->page->out_prod = 0;
547}
548
549static int xenfb_connect_backend(struct xenbus_device *dev,
550				 struct xenfb_info *info)
551{
552	int ret, evtchn, irq;
553	struct xenbus_transaction xbt;
554
555	ret = xenbus_alloc_evtchn(dev, &evtchn);
556	if (ret)
557		return ret;
558	irq = bind_evtchn_to_irqhandler(evtchn, xenfb_event_handler,
559					0, dev->devicetype, info);
560	if (irq < 0) {
561		xenbus_free_evtchn(dev, evtchn);
562		xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
563		return irq;
564	}
565 again:
566	ret = xenbus_transaction_start(&xbt);
567	if (ret) {
568		xenbus_dev_fatal(dev, ret, "starting transaction");
569		goto unbind_irq;
570	}
571	ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
572			    virt_to_gfn(info->page));
573	if (ret)
574		goto error_xenbus;
575	ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
576			    evtchn);
577	if (ret)
578		goto error_xenbus;
579	ret = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
580			    XEN_IO_PROTO_ABI_NATIVE);
581	if (ret)
582		goto error_xenbus;
583	ret = xenbus_printf(xbt, dev->nodename, "feature-update", "1");
584	if (ret)
585		goto error_xenbus;
586	ret = xenbus_transaction_end(xbt, 0);
587	if (ret) {
588		if (ret == -EAGAIN)
589			goto again;
590		xenbus_dev_fatal(dev, ret, "completing transaction");
591		goto unbind_irq;
592	}
593
594	xenbus_switch_state(dev, XenbusStateInitialised);
595	info->irq = irq;
596	return 0;
597
598 error_xenbus:
599	xenbus_transaction_end(xbt, 1);
600	xenbus_dev_fatal(dev, ret, "writing xenstore");
601 unbind_irq:
602	unbind_from_irqhandler(irq, info);
603	return ret;
604}
605
606static void xenfb_disconnect_backend(struct xenfb_info *info)
607{
608	/* Prevent xenfb refresh */
609	info->update_wanted = 0;
610	if (info->irq >= 0)
611		unbind_from_irqhandler(info->irq, info);
612	info->irq = -1;
613}
614
615static void xenfb_backend_changed(struct xenbus_device *dev,
616				  enum xenbus_state backend_state)
617{
618	struct xenfb_info *info = dev_get_drvdata(&dev->dev);
619
620	switch (backend_state) {
621	case XenbusStateInitialising:
622	case XenbusStateInitialised:
623	case XenbusStateReconfiguring:
624	case XenbusStateReconfigured:
625	case XenbusStateUnknown:
626		break;
627
628	case XenbusStateInitWait:
629		xenbus_switch_state(dev, XenbusStateConnected);
630		break;
631
632	case XenbusStateConnected:
633		/*
634		 * Work around xenbus race condition: If backend goes
635		 * through InitWait to Connected fast enough, we can
636		 * get Connected twice here.
637		 */
638		if (dev->state != XenbusStateConnected)
639			/* no InitWait seen yet, fudge it */
640			xenbus_switch_state(dev, XenbusStateConnected);
641
642		if (xenbus_read_unsigned(info->xbdev->otherend,
643					 "request-update", 0))
644			info->update_wanted = 1;
645
646		info->feature_resize = xenbus_read_unsigned(dev->otherend,
647							"feature-resize", 0);
648		break;
649
650	case XenbusStateClosed:
651		if (dev->state == XenbusStateClosed)
652			break;
653		fallthrough;	/* Missed the backend's CLOSING state */
654	case XenbusStateClosing:
655		xenbus_frontend_closed(dev);
656		break;
657	}
658}
659
660static const struct xenbus_device_id xenfb_ids[] = {
661	{ "vfb" },
662	{ "" }
663};
664
665static struct xenbus_driver xenfb_driver = {
666	.ids = xenfb_ids,
667	.probe = xenfb_probe,
668	.remove = xenfb_remove,
669	.resume = xenfb_resume,
670	.otherend_changed = xenfb_backend_changed,
671	.not_essential = true,
672};
673
674static int __init xenfb_init(void)
675{
676	if (!xen_domain())
677		return -ENODEV;
678
679	/* Nothing to do if running in dom0. */
680	if (xen_initial_domain())
681		return -ENODEV;
682
683	if (!xen_has_pv_devices())
684		return -ENODEV;
685
686	return xenbus_register_frontend(&xenfb_driver);
687}
688
689static void __exit xenfb_cleanup(void)
690{
691	xenbus_unregister_driver(&xenfb_driver);
692}
693
694module_init(xenfb_init);
695module_exit(xenfb_cleanup);
696
697MODULE_DESCRIPTION("Xen virtual framebuffer device frontend");
698MODULE_LICENSE("GPL");
699MODULE_ALIAS("xen:vfb");