Archipelago » qemu

/*

 *  xen paravirt framebuffer backend

 *

 *  Copyright IBM, Corp. 2005-2006

 *  Copyright Red Hat, Inc. 2006-2008

 *

 *  Authors:

 *       Anthony Liguori <aliguori@us.ibm.com>,

 *       Markus Armbruster <armbru@redhat.com>,

 *       Daniel P. Berrange <berrange@redhat.com>,

 *       Pat Campbell <plc@novell.com>,

 *       Gerd Hoffmann <kraxel@redhat.com>

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; under version 2 of the License.

 *

 *  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, see <http://www.gnu.org/licenses/>.

 */

#include <stdarg.h>

#include <stdlib.h>

#include <sys/types.h>

#include <fcntl.h>

#include <unistd.h>

#include <sys/mman.h>

#include <errno.h>

#include <stdio.h>

#include <string.h>

#include <time.h>

#include <xs.h>

#include <xenctrl.h>

#include <xen/event_channel.h>

#include <xen/io/xenbus.h>

#include <xen/io/fbif.h>

#include <xen/io/kbdif.h>

#include <xen/io/protocols.h>

#include "hw.h"

#include "console.h"

#include "qemu-char.h"

#include "xen_backend.h"

#ifndef BTN_LEFT

#define BTN_LEFT 0x110 /* from <linux/input.h> */

#endif

/* -------------------------------------------------------------------- */

struct common {

    struct XenDevice  xendev;  /* must be first */

    void              *page;

    DisplayState      *ds;

};

struct XenInput {

    struct common c;

    int abs_pointer_wanted; /* Whether guest supports absolute pointer */

    int button_state;       /* Last seen pointer button state */

    int extended;

    QEMUPutMouseEntry *qmouse;

};

#define UP_QUEUE 8

struct XenFB {

    struct common     c;

    size_t            fb_len;

    int               row_stride;

    int               depth;

    int               width;

    int               height;

    int               offset;

    void              *pixels;

    int               fbpages;

    int               feature_update;

    int               refresh_period;

    int               bug_trigger;

    int               have_console;

    int               do_resize;

    struct {

        int x,y,w,h;

    } up_rects[UP_QUEUE];

    int               up_count;

    int               up_fullscreen;

};

/* -------------------------------------------------------------------- */

static int common_bind(struct common *c)

{

    int mfn;

    if (xenstore_read_fe_int(&c->xendev, "page-ref", &mfn) == -1)

        return -1;

    if (xenstore_read_fe_int(&c->xendev, "event-channel", &c->xendev.remote_port) == -1)

        return -1;

    c->page = xc_map_foreign_range(xen_xc, c->xendev.dom,

                                   XC_PAGE_SIZE,

                                   PROT_READ | PROT_WRITE, mfn);

    if (c->page == NULL)

        return -1;

    xen_be_bind_evtchn(&c->xendev);

    xen_be_printf(&c->xendev, 1, "ring mfn %d, remote-port %d, local-port %d\n",

                  mfn, c->xendev.remote_port, c->xendev.local_port);

    return 0;

}

static void common_unbind(struct common *c)

{

    xen_be_unbind_evtchn(&c->xendev);

    if (c->page) {

        munmap(c->page, XC_PAGE_SIZE);

        c->page = NULL;

    }

}

/* -------------------------------------------------------------------- */

#if 0

/*

 * These two tables are not needed any more, but left in here

 * intentionally as documentation, to show how scancode2linux[]

 * was generated.

 *

 * Tables to map from scancode to Linux input layer keycode.

 * Scancodes are hardware-specific.  These maps assumes a

 * standard AT or PS/2 keyboard which is what QEMU feeds us.

 */

const unsigned char atkbd_set2_keycode[512] = {

     0, 67, 65, 63, 61, 59, 60, 88,  0, 68, 66, 64, 62, 15, 41,117,

     0, 56, 42, 93, 29, 16,  2,  0,  0,  0, 44, 31, 30, 17,  3,  0,

     0, 46, 45, 32, 18,  5,  4, 95,  0, 57, 47, 33, 20, 19,  6,183,

     0, 49, 48, 35, 34, 21,  7,184,  0,  0, 50, 36, 22,  8,  9,185,

     0, 51, 37, 23, 24, 11, 10,  0,  0, 52, 53, 38, 39, 25, 12,  0,

     0, 89, 40,  0, 26, 13,  0,  0, 58, 54, 28, 27,  0, 43,  0, 85,

     0, 86, 91, 90, 92,  0, 14, 94,  0, 79,124, 75, 71,121,  0,  0,

    82, 83, 80, 76, 77, 72,  1, 69, 87, 78, 81, 74, 55, 73, 70, 99,

      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

    217,100,255,  0, 97,165,  0,  0,156,  0,  0,  0,  0,  0,  0,125,

    173,114,  0,113,  0,  0,  0,126,128,  0,  0,140,  0,  0,  0,127,

    159,  0,115,  0,164,  0,  0,116,158,  0,150,166,  0,  0,  0,142,

    157,  0,  0,  0,  0,  0,  0,  0,155,  0, 98,  0,  0,163,  0,  0,

    226,  0,  0,  0,  0,  0,  0,  0,  0,255, 96,  0,  0,  0,143,  0,

      0,  0,  0,  0,  0,  0,  0,  0,  0,107,  0,105,102,  0,  0,112,

    110,111,108,112,106,103,  0,119,  0,118,109,  0, 99,104,119,  0,

};

const unsigned char atkbd_unxlate_table[128] = {

      0,118, 22, 30, 38, 37, 46, 54, 61, 62, 70, 69, 78, 85,102, 13,

     21, 29, 36, 45, 44, 53, 60, 67, 68, 77, 84, 91, 90, 20, 28, 27,

     35, 43, 52, 51, 59, 66, 75, 76, 82, 14, 18, 93, 26, 34, 33, 42,

     50, 49, 58, 65, 73, 74, 89,124, 17, 41, 88,  5,  6,  4, 12,  3,

     11,  2, 10,  1,  9,119,126,108,117,125,123,107,115,116,121,105,

    114,122,112,113,127, 96, 97,120,  7, 15, 23, 31, 39, 47, 55, 63,

     71, 79, 86, 94,  8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 87,111,

     19, 25, 57, 81, 83, 92, 95, 98, 99,100,101,103,104,106,109,110

};

#endif

/*

 * for (i = 0; i < 128; i++) {

 *     scancode2linux[i] = atkbd_set2_keycode[atkbd_unxlate_table[i]];

 *     scancode2linux[i | 0x80] = atkbd_set2_keycode[atkbd_unxlate_table[i] | 0x80];

 * }

 */

static const unsigned char scancode2linux[512] = {

      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15,

     16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,

     32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,

     48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,

     64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,

     80, 81, 82, 83, 99,  0, 86, 87, 88,117,  0,  0, 95,183,184,185,

      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

     93,  0,  0, 89,  0,  0, 85, 91, 90, 92,  0, 94,  0,124,121,  0,

      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

    165,  0,  0,  0,  0,  0,  0,  0,  0,163,  0,  0, 96, 97,  0,  0,

    113,140,164,  0,166,  0,  0,  0,  0,  0,255,  0,  0,  0,114,  0,

    115,  0,150,  0,  0, 98,255, 99,100,  0,  0,  0,  0,  0,  0,  0,

      0,  0,  0,  0,  0,119,119,102,103,104,  0,105,112,106,118,107,

    108,109,110,111,  0,  0,  0,  0,  0,  0,  0,125,126,127,116,142,

      0,  0,  0,143,  0,217,156,173,128,159,158,157,155,226,  0,112,

      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

};

/* Send an event to the keyboard frontend driver */

static int xenfb_kbd_event(struct XenInput *xenfb,

                           union xenkbd_in_event *event)

{

    struct xenkbd_page *page = xenfb->c.page;

    uint32_t prod;

    if (xenfb->c.xendev.be_state != XenbusStateConnected)

        return 0;

    if (!page)

        return 0;

    prod = page->in_prod;

    if (prod - page->in_cons == XENKBD_IN_RING_LEN) {

        errno = EAGAIN;

        return -1;

    }

    xen_mb();                /* ensure ring space available */

    XENKBD_IN_RING_REF(page, prod) = *event;

    xen_wmb();                /* ensure ring contents visible */

    page->in_prod = prod + 1;

    return xen_be_send_notify(&xenfb->c.xendev);

}

/* Send a keyboard (or mouse button) event */

static int xenfb_send_key(struct XenInput *xenfb, bool down, int keycode)

{

    union xenkbd_in_event event;

    memset(&event, 0, XENKBD_IN_EVENT_SIZE);

    event.type = XENKBD_TYPE_KEY;

    event.key.pressed = down ? 1 : 0;

    event.key.keycode = keycode;

    return xenfb_kbd_event(xenfb, &event);

}

/* Send a relative mouse movement event */

static int xenfb_send_motion(struct XenInput *xenfb,

                             int rel_x, int rel_y, int rel_z)

{

    union xenkbd_in_event event;

    memset(&event, 0, XENKBD_IN_EVENT_SIZE);

    event.type = XENKBD_TYPE_MOTION;

    event.motion.rel_x = rel_x;

    event.motion.rel_y = rel_y;

#if __XEN_LATEST_INTERFACE_VERSION__ >= 0x00030207

    event.motion.rel_z = rel_z;

#endif

    return xenfb_kbd_event(xenfb, &event);

}

/* Send an absolute mouse movement event */

static int xenfb_send_position(struct XenInput *xenfb,

                               int abs_x, int abs_y, int z)

{

    union xenkbd_in_event event;

    memset(&event, 0, XENKBD_IN_EVENT_SIZE);

    event.type = XENKBD_TYPE_POS;

    event.pos.abs_x = abs_x;

    event.pos.abs_y = abs_y;

#if __XEN_LATEST_INTERFACE_VERSION__ == 0x00030207

    event.pos.abs_z = z;

#endif

#if __XEN_LATEST_INTERFACE_VERSION__ >= 0x00030208

    event.pos.rel_z = z;

#endif

    return xenfb_kbd_event(xenfb, &event);

}

/*

 * Send a key event from the client to the guest OS

 * QEMU gives us a raw scancode from an AT / PS/2 style keyboard.

 * We have to turn this into a Linux Input layer keycode.

 *

 * Extra complexity from the fact that with extended scancodes

 * (like those produced by arrow keys) this method gets called

 * twice, but we only want to send a single event. So we have to

 * track the '0xe0' scancode state & collapse the extended keys

 * as needed.

 *

 * Wish we could just send scancodes straight to the guest which

 * already has code for dealing with this...

 */

static void xenfb_key_event(void *opaque, int scancode)

{

    struct XenInput *xenfb = opaque;

    int down = 1;

    if (scancode == 0xe0) {

        xenfb->extended = 1;

        return;

    } else if (scancode & 0x80) {

        scancode &= 0x7f;

        down = 0;

    }

    if (xenfb->extended) {

        scancode |= 0x80;

        xenfb->extended = 0;

    }

    xenfb_send_key(xenfb, down, scancode2linux[scancode]);

}

/*

 * Send a mouse event from the client to the guest OS

 *

 * The QEMU mouse can be in either relative, or absolute mode.

 * Movement is sent separately from button state, which has to

 * be encoded as virtual key events. We also don't actually get

 * given any button up/down events, so have to track changes in

 * the button state.

 */

static void xenfb_mouse_event(void *opaque,

                              int dx, int dy, int dz, int button_state)

{

    struct XenInput *xenfb = opaque;

    int dw = ds_get_width(xenfb->c.ds);

    int dh = ds_get_height(xenfb->c.ds);

    int i;

    if (xenfb->abs_pointer_wanted)

        xenfb_send_position(xenfb,

                            dx * (dw - 1) / 0x7fff,

                            dy * (dh - 1) / 0x7fff,

                            dz);

    else

        xenfb_send_motion(xenfb, dx, dy, dz);

    for (i = 0 ; i < 8 ; i++) {

        int lastDown = xenfb->button_state & (1 << i);

        int down = button_state & (1 << i);

        if (down == lastDown)

            continue;

        if (xenfb_send_key(xenfb, down, BTN_LEFT+i) < 0)

            return;

    }

    xenfb->button_state = button_state;

}

static int input_init(struct XenDevice *xendev)

{

    xenstore_write_be_int(xendev, "feature-abs-pointer", 1);

    return 0;

}

static int input_connect(struct XenDevice *xendev)

{

    struct XenInput *in = container_of(xendev, struct XenInput, c.xendev);

    int rc;

    if (xenstore_read_fe_int(xendev, "request-abs-pointer",

                             &in->abs_pointer_wanted) == -1)

        in->abs_pointer_wanted = 0;

    if (!in->c.ds) {

        char *vfb = xenstore_read_str(NULL, "device/vfb");

        if (vfb == NULL) {

            /* there is no vfb, run vkbd on its own */

            in->c.ds = get_displaystate();

        } else {

            g_free(vfb);

            xen_be_printf(xendev, 1, "ds not set (yet)\n");

            return -1;

        }

    }

    rc = common_bind(&in->c);

    if (rc != 0)

        return rc;

    qemu_add_kbd_event_handler(xenfb_key_event, in);

    in->qmouse = qemu_add_mouse_event_handler(xenfb_mouse_event, in,

                                              in->abs_pointer_wanted,

                                              "Xen PVFB Mouse");

    return 0;

}

static void input_disconnect(struct XenDevice *xendev)

{

    struct XenInput *in = container_of(xendev, struct XenInput, c.xendev);

    if (in->qmouse) {

        qemu_remove_mouse_event_handler(in->qmouse);

        in->qmouse = NULL;

    }

    qemu_add_kbd_event_handler(NULL, NULL);

    common_unbind(&in->c);

}

static void input_event(struct XenDevice *xendev)

{

    struct XenInput *xenfb = container_of(xendev, struct XenInput, c.xendev);

    struct xenkbd_page *page = xenfb->c.page;

    /* We don't understand any keyboard events, so just ignore them. */

    if (page->out_prod == page->out_cons)

        return;

    page->out_cons = page->out_prod;

    xen_be_send_notify(&xenfb->c.xendev);

}

/* -------------------------------------------------------------------- */

static void xenfb_copy_mfns(int mode, int count, unsigned long *dst, void *src)

{

    uint32_t *src32 = src;

    uint64_t *src64 = src;

    int i;

    for (i = 0; i < count; i++)

        dst[i] = (mode == 32) ? src32[i] : src64[i];

}

static int xenfb_map_fb(struct XenFB *xenfb)

{

    struct xenfb_page *page = xenfb->c.page;

    char *protocol = xenfb->c.xendev.protocol;

    int n_fbdirs;

    unsigned long *pgmfns = NULL;

    unsigned long *fbmfns = NULL;

    void *map, *pd;

    int mode, ret = -1;

    /* default to native */

    pd = page->pd;

    mode = sizeof(unsigned long) * 8;

    if (!protocol) {

        /*

         * Undefined protocol, some guesswork needed.

         *

         * Old frontends which don't set the protocol use

         * one page directory only, thus pd[1] must be zero.

         * pd[1] of the 32bit struct layout and the lower

         * 32 bits of pd[0] of the 64bit struct layout have

         * the same location, so we can check that ...

         */

        uint32_t *ptr32 = NULL;

        uint32_t *ptr64 = NULL;

#if defined(__i386__)

        ptr32 = (void*)page->pd;

        ptr64 = ((void*)page->pd) + 4;

#elif defined(__x86_64__)

        ptr32 = ((void*)page->pd) - 4;

        ptr64 = (void*)page->pd;

#endif

        if (ptr32) {

            if (ptr32[1] == 0) {

                mode = 32;

                pd   = ptr32;

            } else {

                mode = 64;

                pd   = ptr64;

            }

        }

#if defined(__x86_64__)

    } else if (strcmp(protocol, XEN_IO_PROTO_ABI_X86_32) == 0) {

        /* 64bit dom0, 32bit domU */

        mode = 32;

        pd   = ((void*)page->pd) - 4;

#elif defined(__i386__)

    } else if (strcmp(protocol, XEN_IO_PROTO_ABI_X86_64) == 0) {

        /* 32bit dom0, 64bit domU */

        mode = 64;

        pd   = ((void*)page->pd) + 4;

#endif

    }

    if (xenfb->pixels) {

        munmap(xenfb->pixels, xenfb->fbpages * XC_PAGE_SIZE);

        xenfb->pixels = NULL;

    }

    xenfb->fbpages = (xenfb->fb_len + (XC_PAGE_SIZE - 1)) / XC_PAGE_SIZE;

    n_fbdirs = xenfb->fbpages * mode / 8;

    n_fbdirs = (n_fbdirs + (XC_PAGE_SIZE - 1)) / XC_PAGE_SIZE;

    pgmfns = g_malloc0(sizeof(unsigned long) * n_fbdirs);

    fbmfns = g_malloc0(sizeof(unsigned long) * xenfb->fbpages);

    xenfb_copy_mfns(mode, n_fbdirs, pgmfns, pd);

    map = xc_map_foreign_pages(xen_xc, xenfb->c.xendev.dom,

                               PROT_READ, pgmfns, n_fbdirs);

    if (map == NULL)

        goto out;

    xenfb_copy_mfns(mode, xenfb->fbpages, fbmfns, map);

    munmap(map, n_fbdirs * XC_PAGE_SIZE);

    xenfb->pixels = xc_map_foreign_pages(xen_xc, xenfb->c.xendev.dom,

                                         PROT_READ | PROT_WRITE, fbmfns, xenfb->fbpages);

    if (xenfb->pixels == NULL)

        goto out;

    ret = 0; /* all is fine */

out:

    g_free(pgmfns);

    g_free(fbmfns);

    return ret;

}

static int xenfb_configure_fb(struct XenFB *xenfb, size_t fb_len_lim,

                              int width, int height, int depth,

                              size_t fb_len, int offset, int row_stride)

{

    size_t mfn_sz = sizeof(*((struct xenfb_page *)0)->pd);

    size_t pd_len = sizeof(((struct xenfb_page *)0)->pd) / mfn_sz;

    size_t fb_pages = pd_len * XC_PAGE_SIZE / mfn_sz;

    size_t fb_len_max = fb_pages * XC_PAGE_SIZE;

    int max_width, max_height;

    if (fb_len_lim > fb_len_max) {

        xen_be_printf(&xenfb->c.xendev, 0, "fb size limit %zu exceeds %zu, corrected\n",

                      fb_len_lim, fb_len_max);

        fb_len_lim = fb_len_max;

    }

    if (fb_len_lim && fb_len > fb_len_lim) {

        xen_be_printf(&xenfb->c.xendev, 0, "frontend fb size %zu limited to %zu\n",

                      fb_len, fb_len_lim);

        fb_len = fb_len_lim;

    }

    if (depth != 8 && depth != 16 && depth != 24 && depth != 32) {

        xen_be_printf(&xenfb->c.xendev, 0, "can't handle frontend fb depth %d\n",

                      depth);

        return -1;

    }

    if (row_stride <= 0 || row_stride > fb_len) {

        xen_be_printf(&xenfb->c.xendev, 0, "invalid frontend stride %d\n", row_stride);

        return -1;

    }

    max_width = row_stride / (depth / 8);

    if (width < 0 || width > max_width) {

        xen_be_printf(&xenfb->c.xendev, 0, "invalid frontend width %d limited to %d\n",

                      width, max_width);

        width = max_width;

    }

    if (offset < 0 || offset >= fb_len) {

        xen_be_printf(&xenfb->c.xendev, 0, "invalid frontend offset %d (max %zu)\n",

                      offset, fb_len - 1);

        return -1;

    }

    max_height = (fb_len - offset) / row_stride;

    if (height < 0 || height > max_height) {

        xen_be_printf(&xenfb->c.xendev, 0, "invalid frontend height %d limited to %d\n",

                      height, max_height);

        height = max_height;

    }

    xenfb->fb_len = fb_len;

    xenfb->row_stride = row_stride;

    xenfb->depth = depth;

    xenfb->width = width;

    xenfb->height = height;

    xenfb->offset = offset;

    xenfb->up_fullscreen = 1;

    xenfb->do_resize = 1;

    xen_be_printf(&xenfb->c.xendev, 1, "framebuffer %dx%dx%d offset %d stride %d\n",

                  width, height, depth, offset, row_stride);

    return 0;

}

/* A convenient function for munging pixels between different depths */

#define BLT(SRC_T,DST_T,RSB,GSB,BSB,RDB,GDB,BDB)                        \

    for (line = y ; line < (y+h) ; line++) {                                \

        SRC_T *src = (SRC_T *)(xenfb->pixels                                \

                               + xenfb->offset                                \

                               + (line * xenfb->row_stride)                \

                               + (x * xenfb->depth / 8));                \

        DST_T *dst = (DST_T *)(data                                        \

                               + (line * linesize)                        \

                               + (x * bpp / 8));                        \

        int col;                                                        \

        const int RSS = 32 - (RSB + GSB + BSB);                                \

        const int GSS = 32 - (GSB + BSB);                                \

        const int BSS = 32 - (BSB);                                        \

        const uint32_t RSM = (~0U) << (32 - RSB);                        \

        const uint32_t GSM = (~0U) << (32 - GSB);                        \

        const uint32_t BSM = (~0U) << (32 - BSB);                        \

        const int RDS = 32 - (RDB + GDB + BDB);                                \

        const int GDS = 32 - (GDB + BDB);                                \

        const int BDS = 32 - (BDB);                                        \

        const uint32_t RDM = (~0U) << (32 - RDB);                        \

        const uint32_t GDM = (~0U) << (32 - GDB);                        \

        const uint32_t BDM = (~0U) << (32 - BDB);                        \

        for (col = x ; col < (x+w) ; col++) {                                \

            uint32_t spix = *src;                                        \

            *dst = (((spix << RSS) & RSM & RDM) >> RDS) |                \

                (((spix << GSS) & GSM & GDM) >> GDS) |                        \

                (((spix << BSS) & BSM & BDM) >> BDS);                        \

            src = (SRC_T *) ((unsigned long) src + xenfb->depth / 8);        \

            dst = (DST_T *) ((unsigned long) dst + bpp / 8);                \

        }                                                                \

    }

/*

 * This copies data from the guest framebuffer region, into QEMU's

 * displaysurface. qemu uses 16 or 32 bpp.  In case the pv framebuffer

 * uses something else we must convert and copy, otherwise we can

 * supply the buffer directly and no thing here.

 */

static void xenfb_guest_copy(struct XenFB *xenfb, int x, int y, int w, int h)

{

    int line, oops = 0;

    int bpp = ds_get_bits_per_pixel(xenfb->c.ds);

    int linesize = ds_get_linesize(xenfb->c.ds);

    uint8_t *data = ds_get_data(xenfb->c.ds);

    if (!is_buffer_shared(xenfb->c.ds->surface)) {

        switch (xenfb->depth) {

        case 8:

            if (bpp == 16) {

                BLT(uint8_t, uint16_t,   3, 3, 2,   5, 6, 5);

            } else if (bpp == 32) {

                BLT(uint8_t, uint32_t,   3, 3, 2,   8, 8, 8);

            } else {

                oops = 1;

            }

            break;

        case 24:

            if (bpp == 16) {

                BLT(uint32_t, uint16_t,  8, 8, 8,   5, 6, 5);

            } else if (bpp == 32) {

                BLT(uint32_t, uint32_t,  8, 8, 8,   8, 8, 8);

            } else {

                oops = 1;

            }

            break;

        default:

            oops = 1;

        }

    }

    if (oops) /* should not happen */

        xen_be_printf(&xenfb->c.xendev, 0, "%s: oops: convert %d -> %d bpp?\n",

                      __FUNCTION__, xenfb->depth, bpp);

    dpy_update(xenfb->c.ds, x, y, w, h);

}

#ifdef XENFB_TYPE_REFRESH_PERIOD

static int xenfb_queue_full(struct XenFB *xenfb)

{

    struct xenfb_page *page = xenfb->c.page;

    uint32_t cons, prod;

    if (!page)

        return 1;

    prod = page->in_prod;

    cons = page->in_cons;

    return prod - cons == XENFB_IN_RING_LEN;

}

static void xenfb_send_event(struct XenFB *xenfb, union xenfb_in_event *event)

{

    uint32_t prod;

    struct xenfb_page *page = xenfb->c.page;

    prod = page->in_prod;

    /* caller ensures !xenfb_queue_full() */

    xen_mb();                   /* ensure ring space available */

    XENFB_IN_RING_REF(page, prod) = *event;

    xen_wmb();                  /* ensure ring contents visible */

    page->in_prod = prod + 1;

    xen_be_send_notify(&xenfb->c.xendev);

}

static void xenfb_send_refresh_period(struct XenFB *xenfb, int period)

{

    union xenfb_in_event event;

    memset(&event, 0, sizeof(event));

    event.type = XENFB_TYPE_REFRESH_PERIOD;

    event.refresh_period.period = period;

    xenfb_send_event(xenfb, &event);

}

#endif

/*

 * Periodic update of display.

 * Also transmit the refresh interval to the frontend.

 *

 * Never ever do any qemu display operations

 * (resize, screen update) outside this function.

 * Our screen might be inactive.  When asked for

 * an update we know it is active.

 */

static void xenfb_update(void *opaque)

{

    struct XenFB *xenfb = opaque;

    int i;

    if (xenfb->c.xendev.be_state != XenbusStateConnected)

        return;

    if (xenfb->feature_update) {

#ifdef XENFB_TYPE_REFRESH_PERIOD

        struct DisplayChangeListener *l;

        int period = 99999999;

        int idle = 1;

        if (xenfb_queue_full(xenfb))

            return;

        for (l = xenfb->c.ds->listeners; l != NULL; l = l->next) {

            if (l->idle)

                continue;

            idle = 0;

            if (!l->gui_timer_interval) {

                if (period > GUI_REFRESH_INTERVAL)

                    period = GUI_REFRESH_INTERVAL;

            } else {

                if (period > l->gui_timer_interval)

                    period = l->gui_timer_interval;

            }

        }

        if (idle)

            period = XENFB_NO_REFRESH;

        if (xenfb->refresh_period != period) {

            xenfb_send_refresh_period(xenfb, period);

            xenfb->refresh_period = period;

            xen_be_printf(&xenfb->c.xendev, 1, "refresh period: %d\n", period);

        }

#else

        ; /* nothing */

#endif

    } else {

        /* we don't get update notifications, thus use the

         * sledge hammer approach ... */

        xenfb->up_fullscreen = 1;

    }

    /* resize if needed */

    if (xenfb->do_resize) {

        xenfb->do_resize = 0;

        switch (xenfb->depth) {

        case 16:

        case 32:

            /* console.c supported depth -> buffer can be used directly */

            qemu_free_displaysurface(xenfb->c.ds);

            xenfb->c.ds->surface = qemu_create_displaysurface_from

                (xenfb->width, xenfb->height, xenfb->depth,

                 xenfb->row_stride, xenfb->pixels + xenfb->offset);

            break;

        default:

            /* we must convert stuff */

            qemu_resize_displaysurface(xenfb->c.ds, xenfb->width, xenfb->height);

            break;

        }

        xen_be_printf(&xenfb->c.xendev, 1, "update: resizing: %dx%d @ %d bpp%s\n",

                      xenfb->width, xenfb->height, xenfb->depth,

                      is_buffer_shared(xenfb->c.ds->surface) ? " (shared)" : "");

        dpy_resize(xenfb->c.ds);

        xenfb->up_fullscreen = 1;

    }

    /* run queued updates */

    if (xenfb->up_fullscreen) {

        xen_be_printf(&xenfb->c.xendev, 3, "update: fullscreen\n");

        xenfb_guest_copy(xenfb, 0, 0, xenfb->width, xenfb->height);

    } else if (xenfb->up_count) {

        xen_be_printf(&xenfb->c.xendev, 3, "update: %d rects\n", xenfb->up_count);

        for (i = 0; i < xenfb->up_count; i++)

            xenfb_guest_copy(xenfb,

                             xenfb->up_rects[i].x,

                             xenfb->up_rects[i].y,

                             xenfb->up_rects[i].w,

                             xenfb->up_rects[i].h);

    } else {

        xen_be_printf(&xenfb->c.xendev, 3, "update: nothing\n");

    }

    xenfb->up_count = 0;

    xenfb->up_fullscreen = 0;

}

/* QEMU display state changed, so refresh the framebuffer copy */

static void xenfb_invalidate(void *opaque)

{

    struct XenFB *xenfb = opaque;

    xenfb->up_fullscreen = 1;

}

static void xenfb_handle_events(struct XenFB *xenfb)

{

    uint32_t prod, cons;

    struct xenfb_page *page = xenfb->c.page;

    prod = page->out_prod;

    if (prod == page->out_cons)

        return;

    xen_rmb();                /* ensure we see ring contents up to prod */

    for (cons = page->out_cons; cons != prod; cons++) {

        union xenfb_out_event *event = &XENFB_OUT_RING_REF(page, cons);

        int x, y, w, h;

        switch (event->type) {

        case XENFB_TYPE_UPDATE:

            if (xenfb->up_count == UP_QUEUE)

                xenfb->up_fullscreen = 1;

            if (xenfb->up_fullscreen)

                break;

            x = MAX(event->update.x, 0);

            y = MAX(event->update.y, 0);

            w = MIN(event->update.width, xenfb->width - x);

            h = MIN(event->update.height, xenfb->height - y);

            if (w < 0 || h < 0) {

                xen_be_printf(&xenfb->c.xendev, 1, "bogus update ignored\n");

                break;

            }

            if (x != event->update.x ||

                y != event->update.y ||

                w != event->update.width ||

                h != event->update.height) {

                xen_be_printf(&xenfb->c.xendev, 1, "bogus update clipped\n");

            }

            if (w == xenfb->width && h > xenfb->height / 2) {

                /* scroll detector: updated more than 50% of the lines,

                 * don't bother keeping track of the rectangles then */

                xenfb->up_fullscreen = 1;

            } else {

                xenfb->up_rects[xenfb->up_count].x = x;

                xenfb->up_rects[xenfb->up_count].y = y;

                xenfb->up_rects[xenfb->up_count].w = w;

                xenfb->up_rects[xenfb->up_count].h = h;

                xenfb->up_count++;

            }

            break;

#ifdef XENFB_TYPE_RESIZE

        case XENFB_TYPE_RESIZE:

            if (xenfb_configure_fb(xenfb, xenfb->fb_len,

                                   event->resize.width,

                                   event->resize.height,

                                   event->resize.depth,

                                   xenfb->fb_len,

                                   event->resize.offset,

                                   event->resize.stride) < 0)

                break;

            xenfb_invalidate(xenfb);