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[Xen-changelog] [qemu-xen stable-4.4] cirrus/vnc: zap bitblit support from console code.



commit 784c43b613bc1b73d67c0d133f63bbbbb3197681
Author:     Gerd Hoffmann <kraxel@xxxxxxxxxx>
AuthorDate: Tue Feb 14 19:09:59 2017 +0100
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Tue Mar 21 11:40:45 2017 -0700

    cirrus/vnc: zap bitblit support from console code.
    
    There is a special code path (dpy_gfx_copy) to allow graphic emulation
    notify user interface code about bitblit operations carryed out by
    guests.  It is supported by cirrus and vnc server.  The intended purpose
    is to optimize display scrolls and just send over the scroll op instead
    of a full display update.
    
    This is rarely used these days though because modern guests simply don't
    use the cirrus blitter any more.  Any linux guest using the cirrus drm
    driver doesn't.  Any windows guest newer than winxp doesn't ship with a
    cirrus driver any more and thus uses the cirrus as simple framebuffer.
    
    So this code tends to bitrot and bugs can go unnoticed for a long time.
    See for example commit "3e10c3e vnc: fix qemu crash because of SIGSEGV"
    which fixes a bug lingering in the code for almost a year, added by
    commit "c7628bf vnc: only alloc server surface with clients connected".
    
    Also the vnc server will throttle the frame rate in case it figures the
    network can't keep up (send buffers are full).  This doesn't work with
    dpy_gfx_copy, for any copy operation sent to the vnc client we have to
    send all outstanding updates beforehand, otherwise the vnc client might
    run the client side blit on outdated data and thereby corrupt the
    display.  So this dpy_gfx_copy "optimization" might even make things
    worse on slow network links.
    
    Lets kill it once for all.
    
    This is XSA-211.
    
    Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
    Signed-off-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
 hw/display/cirrus_vga.c | 12 ++-----
 include/ui/console.h    |  8 -----
 ui/console.c            | 28 ---------------
 ui/vnc.c                | 96 -------------------------------------------------
 4 files changed, 3 insertions(+), 141 deletions(-)

diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
index f16960b..f573736 100644
--- a/hw/display/cirrus_vga.c
+++ b/hw/display/cirrus_vga.c
@@ -753,11 +753,6 @@ static void cirrus_do_copy(CirrusVGAState *s, int dst, int 
src, int w, int h)
         }
     }
 
-    /* we have to flush all pending changes so that the copy
-       is generated at the appropriate moment in time */
-    if (notify)
-        graphic_hw_update(s->vga.con);
-
     (*s->cirrus_rop) (s, s->vga.vram_ptr +
                      (s->cirrus_blt_dstaddr & s->cirrus_addr_mask),
                      s->vga.vram_ptr +
@@ -766,10 +761,9 @@ static void cirrus_do_copy(CirrusVGAState *s, int dst, int 
src, int w, int h)
                      s->cirrus_blt_width, s->cirrus_blt_height);
 
     if (notify) {
-        qemu_console_copy(s->vga.con,
-                         sx, sy, dx, dy,
-                         s->cirrus_blt_width / depth,
-                         s->cirrus_blt_height);
+        dpy_gfx_update(s->vga.con, dx, dy,
+                       s->cirrus_blt_width / depth,
+                       s->cirrus_blt_height);
     }
 
     /* we don't have to notify the display that this portion has
diff --git a/include/ui/console.h b/include/ui/console.h
index 98edf41..49222f0 100644
--- a/include/ui/console.h
+++ b/include/ui/console.h
@@ -159,10 +159,6 @@ typedef struct DisplayChangeListenerOps {
                            int x, int y, int w, int h);
     void (*dpy_gfx_switch)(DisplayChangeListener *dcl,
                            struct DisplaySurface *new_surface);
-    void (*dpy_gfx_copy)(DisplayChangeListener *dcl,
-                         int src_x, int src_y,
-                         int dst_x, int dst_y, int w, int h);
-
     void (*dpy_text_cursor)(DisplayChangeListener *dcl,
                             int x, int y);
     void (*dpy_text_resize)(DisplayChangeListener *dcl,
@@ -216,8 +212,6 @@ void unregister_displaychangelistener(DisplayChangeListener 
*dcl);
 void dpy_gfx_update(QemuConsole *con, int x, int y, int w, int h);
 void dpy_gfx_replace_surface(QemuConsole *con,
                              DisplaySurface *surface);
-void dpy_gfx_copy(QemuConsole *con, int src_x, int src_y,
-                  int dst_x, int dst_y, int w, int h);
 void dpy_text_cursor(QemuConsole *con, int x, int y);
 void dpy_text_update(QemuConsole *con, int x, int y, int w, int h);
 void dpy_text_resize(QemuConsole *con, int w, int h);
@@ -295,8 +289,6 @@ void text_consoles_set_display(DisplayState *ds);
 void console_select(unsigned int index);
 void console_color_init(DisplayState *ds);
 void qemu_console_resize(QemuConsole *con, int width, int height);
-void qemu_console_copy(QemuConsole *con, int src_x, int src_y,
-                       int dst_x, int dst_y, int w, int h);
 DisplaySurface *qemu_console_surface(QemuConsole *con);
 DisplayState *qemu_console_displaystate(QemuConsole *console);
 
diff --git a/ui/console.c b/ui/console.c
index e3e8297..a48e4b9 100644
--- a/ui/console.c
+++ b/ui/console.c
@@ -1438,27 +1438,6 @@ void dpy_refresh(DisplayState *s)
     }
 }
 
-void dpy_gfx_copy(QemuConsole *con, int src_x, int src_y,
-                  int dst_x, int dst_y, int w, int h)
-{
-    DisplayState *s = con->ds;
-    DisplayChangeListener *dcl;
-
-    if (!qemu_console_is_visible(con)) {
-        return;
-    }
-    QLIST_FOREACH(dcl, &s->listeners, next) {
-        if (con != (dcl->con ? dcl->con : active_console)) {
-            continue;
-        }
-        if (dcl->ops->dpy_gfx_copy) {
-            dcl->ops->dpy_gfx_copy(dcl, src_x, src_y, dst_x, dst_y, w, h);
-        } else { /* TODO */
-            dcl->ops->dpy_gfx_update(dcl, dst_x, dst_y, w, h);
-        }
-    }
-}
-
 void dpy_text_cursor(QemuConsole *con, int x, int y)
 {
     DisplayState *s = con->ds;
@@ -1830,13 +1809,6 @@ void qemu_console_resize(QemuConsole *s, int width, int 
height)
     dpy_gfx_replace_surface(s, surface);
 }
 
-void qemu_console_copy(QemuConsole *con, int src_x, int src_y,
-                       int dst_x, int dst_y, int w, int h)
-{
-    assert(con->console_type == GRAPHIC_CONSOLE);
-    dpy_gfx_copy(con, src_x, src_y, dst_x, dst_y, w, h);
-}
-
 DisplaySurface *qemu_console_surface(QemuConsole *console)
 {
     return console->surface;
diff --git a/ui/vnc.c b/ui/vnc.c
index 45bed76..70ef75c 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -417,7 +417,6 @@ out_error:
 */
 
 static int vnc_update_client(VncState *vs, int has_dirty);
-static int vnc_update_client_sync(VncState *vs, int has_dirty);
 static void vnc_disconnect_start(VncState *vs);
 
 static void vnc_colordepth(VncState *vs);
@@ -721,93 +720,6 @@ int vnc_send_framebuffer_update(VncState *vs, int x, int 
y, int w, int h)
     return n;
 }
 
-static void vnc_copy(VncState *vs, int src_x, int src_y, int dst_x, int dst_y, 
int w, int h)
-{
-    /* send bitblit op to the vnc client */
-    vnc_lock_output(vs);
-    vnc_write_u8(vs, VNC_MSG_SERVER_FRAMEBUFFER_UPDATE);
-    vnc_write_u8(vs, 0);
-    vnc_write_u16(vs, 1); /* number of rects */
-    vnc_framebuffer_update(vs, dst_x, dst_y, w, h, VNC_ENCODING_COPYRECT);
-    vnc_write_u16(vs, src_x);
-    vnc_write_u16(vs, src_y);
-    vnc_unlock_output(vs);
-    vnc_flush(vs);
-}
-
-static void vnc_dpy_copy(DisplayChangeListener *dcl,
-                         int src_x, int src_y,
-                         int dst_x, int dst_y, int w, int h)
-{
-    VncDisplay *vd = container_of(dcl, VncDisplay, dcl);
-    VncState *vs, *vn;
-    uint8_t *src_row;
-    uint8_t *dst_row;
-    int i, x, y, pitch, inc, w_lim, s;
-    int cmp_bytes;
-
-    vnc_refresh_server_surface(vd);
-    QTAILQ_FOREACH_SAFE(vs, &vd->clients, next, vn) {
-        if (vnc_has_feature(vs, VNC_FEATURE_COPYRECT)) {
-            vs->force_update = 1;
-            vnc_update_client_sync(vs, 1);
-            /* vs might be free()ed here */
-        }
-    }
-
-    /* do bitblit op on the local surface too */
-    pitch = vnc_server_fb_stride(vd);
-    src_row = vnc_server_fb_ptr(vd, src_x, src_y);
-    dst_row = vnc_server_fb_ptr(vd, dst_x, dst_y);
-    y = dst_y;
-    inc = 1;
-    if (dst_y > src_y) {
-        /* copy backwards */
-        src_row += pitch * (h-1);
-        dst_row += pitch * (h-1);
-        pitch = -pitch;
-        y = dst_y + h - 1;
-        inc = -1;
-    }
-    w_lim = w - (16 - (dst_x % 16));
-    if (w_lim < 0)
-        w_lim = w;
-    else
-        w_lim = w - (w_lim % 16);
-    for (i = 0; i < h; i++) {
-        for (x = 0; x <= w_lim;
-                x += s, src_row += cmp_bytes, dst_row += cmp_bytes) {
-            if (x == w_lim) {
-                if ((s = w - w_lim) == 0)
-                    break;
-            } else if (!x) {
-                s = (16 - (dst_x % 16));
-                s = MIN(s, w_lim);
-            } else {
-                s = 16;
-            }
-            cmp_bytes = s * VNC_SERVER_FB_BYTES;
-            if (memcmp(src_row, dst_row, cmp_bytes) == 0)
-                continue;
-            memmove(dst_row, src_row, cmp_bytes);
-            QTAILQ_FOREACH(vs, &vd->clients, next) {
-                if (!vnc_has_feature(vs, VNC_FEATURE_COPYRECT)) {
-                    set_bit(((x + dst_x) / 16), vs->dirty[y]);
-                }
-            }
-        }
-        src_row += pitch - w * VNC_SERVER_FB_BYTES;
-        dst_row += pitch - w * VNC_SERVER_FB_BYTES;
-        y += inc;
-    }
-
-    QTAILQ_FOREACH(vs, &vd->clients, next) {
-        if (vnc_has_feature(vs, VNC_FEATURE_COPYRECT)) {
-            vnc_copy(vs, src_x, src_y, dst_x, dst_y, w, h);
-        }
-    }
-}
-
 static void vnc_mouse_set(DisplayChangeListener *dcl,
                           int x, int y, int visible)
 {
@@ -873,13 +785,6 @@ static int find_and_clear_dirty_height(struct VncState *vs,
     return h;
 }
 
-static int vnc_update_client_sync(VncState *vs, int has_dirty)
-{
-    int ret = vnc_update_client(vs, has_dirty);
-    vnc_jobs_join(vs);
-    return ret;
-}
-
 static int vnc_update_client(VncState *vs, int has_dirty)
 {
     if (vs->need_update && vs->csock != -1) {
@@ -2920,7 +2825,6 @@ static void vnc_listen_websocket_read(void *opaque)
 static const DisplayChangeListenerOps dcl_ops = {
     .dpy_name          = "vnc",
     .dpy_refresh       = vnc_refresh,
-    .dpy_gfx_copy      = vnc_dpy_copy,
     .dpy_gfx_update    = vnc_dpy_update,
     .dpy_gfx_switch    = vnc_dpy_switch,
     .dpy_mouse_set     = vnc_mouse_set,
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#stable-4.4

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