Paravirt framebuffer kernel infrastructure [1/6]

Basic kernel space support for virtual framebuffer and keyboard. This is the work Markus did to port Anthony's original code to use xenstore and for current kernels. It should include all of the fixes from the last submission

Jeremy

diff -r ec03b24a2d83 -r 6ca424e1867e linux-2.6-xen-sparse/arch/i386/kernel/setup-xen.c
@@ -1871,8 +1871,12 @@ void __init setup_arch(char **cmdline_p)
 #endif
 #endif
 	} else {
+#if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
+		conswitchp = &dummy_con;
+#else
 		extern int console_use_vt;
 		console_use_vt = 0;
+#endif
 	}
 }
 

diff -r ec03b24a2d83 -r 6ca424e1867e linux-2.6-xen-sparse/drivers/xen/Kconfig
@@ -172,6 +172,29 @@ config XEN_NETDEV_FRONTEND
 	  dedicated device-driver domain, or your master control domain
 	  (domain 0), then you almost certainly want to say Y here.
 
+config XEN_FRAMEBUFFER
+	tristate "Framebuffer-device frontend driver"
+	depends on XEN && FB
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	default y
+	help
+	  The framebuffer-device frontend drivers allows the kernel to create a
+	  virtual framebuffer.  This framebuffer can be viewed in another
+	  domain.  Unless this domain has access to a real video card, you
+	  probably want to say Y here.
+
+config XEN_KEYBOARD
+	tristate "Keyboard-device frontend driver"
+	depends on XEN
+	default y
+	help
+	  The keyboard-device frontend driver allows the kernel to create a
+	  virtual keyboard.  This keyboard can then be driven by another
+	  domain.  If you've said Y to CONFIG_XEN_FRAMEBUFFER, you probably
+	  want to say Y here.
+
 config XEN_SCRUB_PAGES
 	bool "Scrub memory before freeing it to Xen"
 	default y

diff -r ec03b24a2d83 -r 6ca424e1867e linux-2.6-xen-sparse/drivers/xen/Makefile
@@ -15,3 +15,5 @@ obj-$(CONFIG_XEN_NETDEV_FRONTEND)	+= net
 obj-$(CONFIG_XEN_NETDEV_FRONTEND)	+= netfront/
 obj-$(CONFIG_XEN_PCIDEV_BACKEND)	+= pciback/
 obj-$(CONFIG_XEN_PCIDEV_FRONTEND)	+= pcifront/
+obj-$(CONFIG_XEN_FRAMEBUFFER)		+= xenfb/
+obj-$(CONFIG_XEN_KEYBOARD)		+= xenkbd/

diff -r ec03b24a2d83 -r 6ca424e1867e linux-2.6-xen-sparse/mm/memory.c
@@ -881,6 +881,7 @@ unsigned long zap_page_range(struct vm_a
 		tlb_finish_mmu(tlb, address, end);
 	return end;
 }
+EXPORT_SYMBOL(zap_page_range);
 
 /*
  * Do a quick page-table lookup for a single page.

diff -r ec03b24a2d83 -r 6ca424e1867e linux-2.6-xen-sparse/drivers/xen/xenfb/Makefile
@@ -0,0 +1,1 @@
+obj-$(CONFIG_XEN_FRAMEBUFFER)	:= xenfb.o

diff -r ec03b24a2d83 -r 6ca424e1867e linux-2.6-xen-sparse/drivers/xen/xenkbd/Makefile
@@ -0,0 +1,1 @@
+obj-$(CONFIG_XEN_KEYBOARD)	+= xenkbd.o

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This patch is indeed identical to the one I submitted last.

Hi,

IMHO, I think it should be better to move the refresh timer from kernel to user space, and to know which part of the image to refresh, a bitmap array should be easy to use than an event ring.

I propose following patches to do this.

Any comments ?

Regards,
Laurent

Index: xen-3.0-testing.hg/linux-2.6.16.13-xen/drivers/xen/xenfb/xenfb.c
===================================================================
--- xen-3.0-testing.hg.orig/linux-2.6.16.13-xen/drivers/xen/xenfb/xenfb.c

2006-08-29 12:16:49.000000000 +0200

+++ xen-3.0-testing.hg/linux-2.6.16.13-xen/drivers/xen/xenfb/xenfb.c 2006-08-29
16:15:04.000000000 +0200
@@ -24,118 +24,33 @@
#include <linux/xenfb.h>
#include <linux/kthread.h>

-static int xenfb_fps = 20;
-static unsigned long xenfb_mem_len = 2 * 1024 * 1024; +static unsigned long xenfb_mem_len = XENFB_VIDEOMEM_SIZE;

struct xenfb_mapping
{
- struct list_head next;
struct vm_area_struct *vma;
atomic_t map_refs;
- int faults;
struct xenfb_info *info;
};

struct xenfb_info
{
- struct task_struct *kthread;
- wait_queue_head_t wq;
-
unsigned char *fb;
struct fb_fix_screeninfo *fix;
struct fb_var_screeninfo *var;
struct fb_info *fb_info;
- struct timer_list refresh;
- int dirty;
int y1, y2;
int x1, x2;

struct semaphore mm_lock;
int nr_pages;
struct page **pages;
- struct list_head mappings;

unsigned evtchn;
struct xenfb_page *page;
unsigned long *mfns;
};

-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;
- if (prod - info->page->out_cons == XENFB_RING_SIZE(info->page->out))
- return; /* ring buffer full, event lost */
- XENFB_RING_REF(info->page->out, prod) = event;
- info->page->out_prod = prod + 1;
-
- notify_remote_via_evtchn(info->evtchn);
-}
-
-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_RING_SIZE(info->page->out);
-}
-
-static void xenfb_update_screen(struct xenfb_info *info)
-{
- int y1, y2, x1, x2;
- struct list_head *item;
- struct xenfb_mapping *map;
-
- if (xenfb_queue_full(info))
- return;
-
- y1 = info->y1;
- y2 = info->y2;
- x1 = info->x1;
- x2 = info->x2;
- info->dirty = info->y1 = info->y2 = info->x1 = info->x2 = 0;
- down(&info->mm_lock);
- list_for_each(item, &info->mappings) {
- map = list_entry(item, struct xenfb_mapping, next);
- if (!map->faults)
- continue;
- zap_page_range(map->vma, map->vma->vm_start,
- map->vma->vm_end - map->vma->vm_start, NULL);
- map->faults = 0;
- }
- up(&info->mm_lock);
-
- xenfb_do_update(info, x1, y1, x2 - x1, y2 - y1);
-}
-
-static int xenfb_thread(void *data)
-{
- struct xenfb_info *info = data;
- DECLARE_WAITQUEUE(wait, current);
-
- add_wait_queue(&info->wq, &wait);
- for (;;) {
- if (kthread_should_stop())
- break;
- if (info->dirty)
- xenfb_update_screen(info);
- set_current_state(TASK_INTERRUPTIBLE);
- schedule();
- }
- remove_wait_queue(&info->wq, &wait);
- return 0;
-}
-
static int xenfb_setcolreg(unsigned regno, unsigned red, unsigned green,
unsigned blue, unsigned transp, struct fb_info *info)
@@ -164,50 +79,24 @@ static int xenfb_setcolreg(unsigned regn
return 0;
}

-static void xenfb_timer(unsigned long data)
+static void xenfb_update_pages(struct xenfb_info *info, int x, int y, int w, int h)
{
- struct xenfb_info *info = (struct xenfb_info *)data;
- info->dirty++;
- wake_up(&info->wq);
-}
-
-static void xenfb_refresh(struct xenfb_info *info,
- int x1, int y1, int w, int h)
-{
- int y2, x2;
-
- y2 = y1 + h;
- x2 = x1 + w;
- if (info->y2 == 0) {
- info->y1 = y1;
- info->y2 = y2;
- }
- if (info->x2 == 0) {
- info->x1 = x1;
- info->x2 = x2;
- }
+ int begin, end;
+ int pgnr;

- if (info->y1 > y1)
- info->y1 = y1;
- if (info->y2 < y2)
- info->y2 = y2;
- if (info->x1 > x1)
- info->x1 = x1;
- if (info->x2 < x2)
- info->x2 = x2;
+ begin = (y * info->page->line_length + x * (info->page->depth / 8)) >> PAGE_SHIFT;
+ end = ((y + h - 1) * info->page->line_length +
+ ((x + w - 1) * (info->page->depth / 8))) >> PAGE_SHIFT;

- if (timer_pending(&info->refresh))
- return;
-
- mod_timer(&info->refresh, jiffies + HZ/xenfb_fps);
+ for (pgnr = begin; pgnr <= end; pgnr++)
+ set_bit(pgnr, &info->page->dirty_pages);
}

static void xenfb_fillrect(struct fb_info *p, const struct fb_fillrect *rect) {
struct xenfb_info *info = p->par;
-
cfb_fillrect(p, rect);
- xenfb_refresh(info, rect->dx, rect->dy, rect->width, rect->height);
+ xenfb_update_pages(info, rect->dx, rect->dy, rect->width, rect->height);
}

static void xenfb_imageblit(struct fb_info *p, const struct fb_image *image)
@@ -215,7 +104,7 @@ static void xenfb_imageblit(struct fb_in
struct xenfb_info *info = p->par;

cfb_imageblit(p, image);
- xenfb_refresh(info, image->dx, image->dy, image->width, image->height);
+ xenfb_update_pages(info, image->dx, image->dy, image->width, image->height);
}

static void xenfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
@@ -223,7 +112,7 @@ static void xenfb_copyarea(struct fb_inf
struct xenfb_info *info = p->par;

cfb_copyarea(p, area);
- xenfb_refresh(info, area->dx, area->dy, area->width, area->height);
+ xenfb_update_pages(info, area->dx, area->dy, area->width, area->height);
}

static void xenfb_vm_open(struct vm_area_struct *vma)
@@ -239,7 +128,7 @@ static void xenfb_vm_close(struct vm_are

down(&info->mm_lock);
if (atomic_dec_and_test(&map->map_refs)) {
- list_del(&map->next);
+ vma->vm_private_data = NULL;
kfree(map);
}
up(&info->mm_lock);
@@ -252,7 +141,6 @@ static struct page *xenfb_vm_nopage(stru
struct xenfb_info *info = map->info;
int pgnr = (vaddr - vma->vm_start) >> PAGE_SHIFT; struct page *page;
- int y1, y2;

if (pgnr >= info->nr_pages)
return NOPAGE_SIGBUS;
@@ -260,13 +148,10 @@ static struct page *xenfb_vm_nopage(stru
down(&info->mm_lock);
page = info->pages[pgnr];
get_page(page);
- map->faults++;

- y1 = pgnr * PAGE_SIZE / info->fix->line_length;
- y2 = (pgnr * PAGE_SIZE + PAGE_SIZE - 1) / info->fix->line_length;
- if (y2 > info->var->yres)
- y2 = info->var->yres;
- xenfb_refresh(info, 0, y1, info->var->xres, y2 - y1);
+ set_bit(pgnr, &info->page->dirty_pages);
+ zap_page_range(map->vma, map->vma->vm_start, map->vma->vm_end -
map->vma->vm_start, NULL);
+
up(&info->mm_lock);

if (type)
@@ -309,10 +194,8 @@ static int xenfb_mmap(struct fb_info *fb
memset(map, 0, sizeof(*map));

map->vma = vma;
- map->faults = 0;
map->info = info; atomic_set(&map->map_refs, 1);
- list_add(&map->next, &info->mappings);
vma->vm_ops = &xenfb_vm_ops; vma->vm_flags |= (VM_DONTEXPAND | VM_RESERVED); vma->vm_private_data = map;
@@ -375,8 +258,6 @@ static int __init xenfb_probe(void)
return -ENOMEM;
memset(info, 0, sizeof(*info));

- INIT_LIST_HEAD(&info->mappings);
-
info->fb = vmalloc(xenfb_mem_len);
if (info->fb == NULL)
goto error;
@@ -416,6 +297,8 @@ static int __init xenfb_probe(void)
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;
+ for (i = 0; i < XENFB_DIRTY_PAGES_SIZE; i++)
+ info->page->dirty_pages[i] = 0xFF;

ret = bind_evtchn_to_irqhandler(info->evtchn, xenfb_event_handler,
0, "xenfb", info);
@@ -464,12 +347,6 @@ static int __init xenfb_probe(void)
info->var = &fb_info->var;

init_MUTEX(&info->mm_lock);
- init_waitqueue_head(&info->wq);
- init_timer(&info->refresh);
- info->refresh.function = xenfb_timer;
- info->refresh.data = (unsigned long)info;
-
- info->kthread = kthread_run(xenfb_thread, info, "xenfb thread");

ret = register_framebuffer(fb_info);
if (ret)
@@ -518,30 +395,6 @@ static int __init xenfb_probe(void)
return -ENODEV;
}

-void xenfb_resume(void)
-{
-#if 0 /* FIXME */
- int i, ret;
-
- xenfb_info->page = mfn_to_virt(xen_start_info->fbdev_mfn);
- for (i = 0; i < xenfb_info->nr_pages; i++)
- xenfb_info->mfns[i] = vmalloc_to_mfn(xenfb_info->fb + i * PAGE_SIZE);
- xenfb_info->page->pd[0] = vmalloc_to_mfn(xenfb_info->mfns);
-
- if (xenfb_irq)
- unbind_from_irqhandler(xenfb_irq, NULL);
-
- printk("xenfb: resume(%d)\n", xen_start_info->fbdev_evtchn);
- ret = bind_evtchn_to_irqhandler(xen_start_info->fbdev_evtchn,
- xenfb_event_handler, 0, "xenfb", xenfb_info);
- if (ret <= 0)
- return;
- xenfb_irq = ret;
-#else
- printk(KERN_DEBUG "xenfb_resume not implemented\n");
-#endif
-}
-
static int __init xenfb_init(void)
{
return xenfb_probe();
Index: xen-3.0-testing.hg/linux-2.6.16.13-xen/include/linux/xenfb.h
===================================================================
--- xen-3.0-testing.hg.orig/linux-2.6.16.13-xen/include/linux/xenfb.h 2006-08-29
12:16:49.000000000 +0200
+++ xen-3.0-testing.hg/linux-2.6.16.13-xen/include/linux/xenfb.h 2006-08-29
12:36:06.000000000 +0200
@@ -27,20 +27,10 @@ struct xenfb_motion
__u16 y; /* The new y coordinate */
};

-struct xenfb_update
-{

-	__u8 type;          /* XENFB_TYPE_UPDATE */
-	__u16 x;            /* source x */
-	__u16 y;            /* source y */
-	__u16 width;        /* rect width */
-	__u16 height;       /* rect height */

-};
-
union xenfb_out_event
{
__u8 type;
struct xenfb_motion motion;
- struct xenfb_update update;
char _[40];
};

@@ -69,11 +59,14 @@ union xenfb_in_event
/* shared page */

#define XENFB_IN_RING_SIZE (1024 / 40)
-#define XENFB_OUT_RING_SIZE (2048 / 40)
+#define XENFB_OUT_RING_SIZE (1024 / 40)

#define XENFB_RING_SIZE(ring) (sizeof((ring)) / sizeof(*(ring))) #define XENFB_RING_REF(ring, idx) (ring)[(idx) % XENFB_RING_SIZE((ring))]

+#define XENFB_VIDEOMEM_SIZE (2 * 1024 * 1024)
+#define XENFB_DIRTY_PAGES_SIZE ((((XENFB_VIDEOMEM_SIZE + 4096 - 1)/ 4096) + 7) / 8)
+
struct xenfb_page
{
__u8 initialized;
@@ -90,6 +83,8 @@ struct xenfb_page

union xenfb_in_event in[XENFB_IN_RING_SIZE]; union xenfb_out_event out[XENFB_OUT_RING_SIZE];
+
+ __u8 dirty_pages[XENFB_DIRTY_PAGES_SIZE];
};

void xenfb_resume(void);

Index: vncfb/sdlfb.c
===================================================================
@@ -7,13 +7,17 @@ typedef unsigned long kernel_ulong_t;
 #include <linux/input.h>
 #include "xenfb.h"
 
+extern char *get_bitmap(struct xenfb *xenfb, int *size);
+
+#define IPS	(30)
+
 struct data
 {
 	SDL_Surface *dst;
 	SDL_Surface *src;
 };
 
-void sdl_update(struct xenfb *xenfb, int x, int y, int width, int height)
+static void sdl_update(struct xenfb *xenfb, int x, int y, int width, int height)
 {
 	struct data *data = xenfb->user_data;
 	SDL_Rect r = { x, y, width, height };

@@ -21,6 +25,65 @@ void sdl_update(struct xenfb *xenfb, int
 	SDL_UpdateRect(data->dst, x, y, width, height);
 }
 
+static __inline__ int test_and_clear_bit(int nr, volatile void * addr)
+{
+	int oldbit;
+	__asm__ __volatile__( "lock ; "
+			"btrl %2,%1\n\tsbbl %0,%0"
+			:"=r" (oldbit),"+m" (*(volatile long *) addr)
+			:"Ir" (nr) : "memory");
+	return oldbit;
+}
+
+static void sdl_memory_udpate(struct xenfb *xenfb, int begin, int end)
+{
+	int y1, y2;
+	begin *= 4096;
+	end *= 4096;
+
+	y1 = begin / xenfb->row_stride;
+	y2 = end / xenfb->row_stride;
+
+	if (y1 != y2)
+		sdl_update(xenfb, 0, y1, xenfb->width, y2 - y1);
+	else {
+		int x1, x2;
+		x1 = (begin - y1 * xenfb->row_stride) / (xenfb->depth / 8);
+		x2 = (begin - y2 * xenfb->row_stride) / (xenfb->depth / 8);
+		sdl_update(xenfb, x1, y1, xenfb->width - x1, 1);
+		sdl_update(xenfb, x1, y1 + 1, x2 - x1 + 1, y2 - y1 - 1);
+		sdl_update(xenfb, 0, y2, x2 - 1, 1);
+	}
+}
+
+static Uint32 refresh_handler(Uint32 interval, void *param)
+{
+#define WSIZE	(sizeof(unsigned long)*8)
+	struct xenfb * xenfb = param;
+	int size;
+	unsigned long *bitmap;
+	int i, j;
+	int begin = -1;
+	bitmap = (unsigned long*)get_bitmap(xenfb, &size);
+	for (i = 0; i < size / sizeof(unsigned long); i++) {
+		for (j = 0; j < WSIZE; j++) {
+			if (test_and_clear_bit(j, bitmap + i)) {
+				if (begin == -1)
+					begin = i * WSIZE + j;
+			} else if (begin != -1) {
+				sdl_memory_udpate(xenfb,
+					  	begin,
+					  	i * WSIZE + j);
+				begin = -1;
+			}
+		}
+	}
+	if (begin != -1) {
+		sdl_memory_udpate(xenfb, begin, size * WSIZE - 1);
+	}
+	return interval;	
+}
+
 int sdl2linux[1024] = {
 	[9] = KEY_ESC,
 	[67] = KEY_F1,

@@ -132,13 +195,11 @@ int sdl2linux[1024] = {
 int main(int argc, char **argv)
 {
 	struct xenfb *xenfb;
-	int fd;
 	int domid;
-	fd_set readfds;
 	struct data data;
 	SDL_Rect r;
-	struct timeval tv = { 0, 500 };
 	int do_quit = 0;
+	SDL_TimerID refreshTimer;
 
 
 	if (argc != 2)

@@ -153,12 +214,10 @@ int main(int argc, char **argv)
 	if (!xenfb_set_domid(xenfb, domid))
 		return 1;
 
-	SDL_Init(SDL_INIT_VIDEO);
-
-	fd = xenfb_get_fileno(xenfb);
+	SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER);
 
 	data.dst = SDL_SetVideoMode(xenfb->width, xenfb->height, xenfb->depth,
-				    SDL_SWSURFACE);
+				    SDL_HWSURFACE);
 	data.src = SDL_CreateRGBSurfaceFrom(xenfb->pixels,
 					    xenfb->width, xenfb->height,
 					    xenfb->depth, xenfb->row_stride,

@@ -170,15 +229,12 @@ int main(int argc, char **argv)
 	SDL_BlitSurface(data.src, &r, data.dst, &r);
 	SDL_UpdateRect(data.dst, 0, 0, xenfb->width, xenfb->height);
 
-	xenfb->update = sdl_update;
 	xenfb->user_data = &data;
 
-	FD_ZERO(&readfds);
-	FD_SET(fd, &readfds);
-
 	SDL_ShowCursor(0);
 
-	while (!do_quit && select(fd + 1, &readfds, NULL, NULL, &tv) != -1) {
+	refreshTimer = SDL_AddTimer(1000 / IPS, refresh_handler, xenfb);
+	while (!do_quit) {
 		SDL_Event event;
 
 		while (SDL_PollEvent(&event)) {

@@ -207,15 +263,9 @@ int main(int argc, char **argv)
 				break;
 			}
 		}
-		if (FD_ISSET(fd, &readfds))
-			xenfb_on_incoming(xenfb);
-
-		FD_ZERO(&readfds);
-		FD_SET(fd, &readfds);
-
-		tv = (struct timeval){0, 500};
 	}
 
+	SDL_RemoveTimer(refreshTimer);
 	xenfb_delete(xenfb);
 
 	SDL_Quit();

Index: vncfb/xenfb.c
===================================================================
@@ -69,15 +69,6 @@ struct xenfb *xenfb_new(void)
 	return &xenfb->pub;
 }
 
-int xenfb_get_fileno(struct xenfb *xenfb_pub)
-{
-	struct xenfb_private *xenfb = (struct xenfb_private *)xenfb_pub;
-	if (xenfb->domid == -1)
-		return -1;
-
-	return xenfb->fd;
-}
-
 static void xenfb_unset_domid(struct xenfb_private *xenfb)
 {
 	struct ioctl_evtchn_unbind unbind;

@@ -357,10 +348,10 @@ bool xenfb_set_domid(struct xenfb *xenfb
 	return false;
 }
 
-static void xenfb_update(struct xenfb_private *xenfb, int x, int y, int width,

int height)
+char *get_bitmap(struct xenfb_private *xenfb, int *size)
{
- if (xenfb->pub.update)
- xenfb->pub.update(&xenfb->pub, x, y, width, height);
+ *size = XENFB_DIRTY_PAGES_SIZE;
+ return xenfb->fb_info->dirty_pages;
}

static void xenfb_on_fb_event(struct xenfb_private *xenfb)
@@ -375,7 +366,6 @@ static void xenfb_on_fb_event(struct xen

switch (event->type) {
case XENFB_TYPE_UPDATE:
- xenfb_update(xenfb, event->update.x, event->update.y, event->update.width,
event->update.height);
break;
}
}

Index: vncfb/xenfb.h
===================================================================
@@ -14,8 +14,6 @@ struct xenfb
 	int height;
 
 	void *user_data;
-
-	void (*update)(struct xenfb *xenfb, int x, int y, int width, int height);
 };
 
 struct xenfb *xenfb_new(void);

                [email protected]
         Bull, Architect of an Open World (TM)
+----- "Any sufficiently advanced technology is ----+
| indistinguishable from magic." - Arthur C. Clarke |

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