[Qemu-devel] [PATCH 09/10] tcx: make display updates thread safe

[Gerd Hoffmann <kraxel@redhat.com>]

From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
---
 hw/display/tcx.c | 85 +++++++++++++++++++-------------------------------------
 1 file changed, 29 insertions(+), 56 deletions(-)

diff --git a/hw/display/tcx.c b/hw/display/tcx.c
index 15172f0..a890e49 100644
--- a/hw/display/tcx.c
+++ b/hw/display/tcx.c
@@ -98,44 +98,28 @@ static void tcx_set_dirty(TCXState *s)
     memory_region_set_dirty(&s->vram_mem, 0, MAXX * MAXY);
 }
 
-static inline int tcx_check_dirty(TCXState *s, ram_addr_t page)
+static inline int tcx_check_dirty(TCXState *s, DirtyBitmapSnapshot *snap,
+                                  ram_addr_t page)
 {
-    return memory_region_get_dirty(&s->vram_mem, page, TARGET_PAGE_SIZE,
-                                   DIRTY_MEMORY_VGA);
+    return memory_region_snapshot_get_dirty(&s->vram_mem, snap, page,
+                                            TARGET_PAGE_SIZE - 1);
 }
 
-static inline int tcx24_check_dirty(TCXState *s, ram_addr_t page,
-                                    ram_addr_t page24, ram_addr_t cpage)
+static inline int tcx24_check_dirty(TCXState *s, DirtyBitmapSnapshot *snap,
+                                    ram_addr_t page, ram_addr_t page24,
+                                    ram_addr_t cpage)
 {
     int ret;
 
-    ret = memory_region_get_dirty(&s->vram_mem, page, TARGET_PAGE_SIZE,
-                                  DIRTY_MEMORY_VGA);
-    ret |= memory_region_get_dirty(&s->vram_mem, page24, TARGET_PAGE_SIZE * 4,
-                                   DIRTY_MEMORY_VGA);
-    ret |= memory_region_get_dirty(&s->vram_mem, cpage, TARGET_PAGE_SIZE * 4,
-                                   DIRTY_MEMORY_VGA);
+    ret = memory_region_snapshot_get_dirty(&s->vram_mem, snap, page,
+                                           TARGET_PAGE_SIZE);
+    ret |= memory_region_snapshot_get_dirty(&s->vram_mem, snap, page24,
+                                            TARGET_PAGE_SIZE * 4);
+    ret |= memory_region_snapshot_get_dirty(&s->vram_mem, snap, cpage,
+                                            TARGET_PAGE_SIZE * 4);
     return ret;
 }
 
-static inline void tcx24_reset_dirty(TCXState *ts, ram_addr_t page_min,
-                               ram_addr_t page_max, ram_addr_t page24,
-                              ram_addr_t cpage)
-{
-    memory_region_reset_dirty(&ts->vram_mem,
-                              page_min,
-                              (page_max - page_min) + TARGET_PAGE_SIZE,
-                              DIRTY_MEMORY_VGA);
-    memory_region_reset_dirty(&ts->vram_mem,
-                              page24 + page_min * 4,
-                              (page_max - page_min) * 4 + TARGET_PAGE_SIZE,
-                              DIRTY_MEMORY_VGA);
-    memory_region_reset_dirty(&ts->vram_mem,
-                              cpage + page_min * 4,
-                              (page_max - page_min) * 4 + TARGET_PAGE_SIZE,
-                              DIRTY_MEMORY_VGA);
-}
-
 static void update_palette_entries(TCXState *s, int start, int end)
 {
     DisplaySurface *surface = qemu_console_surface(s->con);
@@ -325,7 +309,8 @@ static void tcx_update_display(void *opaque)
 {
     TCXState *ts = opaque;
     DisplaySurface *surface = qemu_console_surface(ts->con);
-    ram_addr_t page, page_min, page_max;
+    ram_addr_t page;
+    DirtyBitmapSnapshot *snap = NULL;
     int y, y_start, dd, ds;
     uint8_t *d, *s;
     void (*f)(TCXState *s1, uint8_t *dst, const uint8_t *src, int width);
@@ -337,8 +322,6 @@ static void tcx_update_display(void *opaque)
 
     page = 0;
     y_start = -1;
-    page_min = -1;
-    page_max = 0;
     d = surface_data(surface);
     s = ts->vram;
     dd = surface_stride(surface);
@@ -364,14 +347,14 @@ static void tcx_update_display(void *opaque)
     }
 
     memory_region_sync_dirty_bitmap(&ts->vram_mem);
+    snap = memory_region_snapshot_and_clear_dirty(&ts->vram_mem, 0x0,
+                                                  memory_region_size(&ts->vram_mem),
+                                                  DIRTY_MEMORY_VGA);
+
     for (y = 0; y < ts->height; page += TARGET_PAGE_SIZE) {
-        if (tcx_check_dirty(ts, page)) {
+        if (tcx_check_dirty(ts, snap, page)) {
             if (y_start < 0)
                 y_start = y;
-            if (page < page_min)
-                page_min = page;
-            if (page > page_max)
-                page_max = page;
 
             f(ts, d, s, ts->width);
             if (y >= ts->cursy && y < ts->cursy + 32 && ts->cursx < ts->width) {
@@ -421,20 +404,15 @@ static void tcx_update_display(void *opaque)
         dpy_gfx_update(ts->con, 0, y_start,
                        ts->width, y - y_start);
     }
-    /* reset modified pages */
-    if (page_max >= page_min) {
-        memory_region_reset_dirty(&ts->vram_mem,
-                                  page_min,
-                                  (page_max - page_min) + TARGET_PAGE_SIZE,
-                                  DIRTY_MEMORY_VGA);
-    }
+    g_free(snap);
 }
 
 static void tcx24_update_display(void *opaque)
 {
     TCXState *ts = opaque;
     DisplaySurface *surface = qemu_console_surface(ts->con);
-    ram_addr_t page, page_min, page_max, cpage, page24;
+    ram_addr_t page, cpage, page24;
+    DirtyBitmapSnapshot *snap = NULL;
     int y, y_start, dd, ds;
     uint8_t *d, *s;
     uint32_t *cptr, *s24;
@@ -447,8 +425,6 @@ static void tcx24_update_display(void *opaque)
     page24 = ts->vram24_offset;
     cpage = ts->cplane_offset;
     y_start = -1;
-    page_min = -1;
-    page_max = 0;
     d = surface_data(surface);
     s = ts->vram;
     s24 = ts->vram24;
@@ -457,15 +433,15 @@ static void tcx24_update_display(void *opaque)
     ds = 1024;
 
     memory_region_sync_dirty_bitmap(&ts->vram_mem);
+    snap = memory_region_snapshot_and_clear_dirty(&ts->vram_mem, 0x0,
+                                                  memory_region_size(&ts->vram_mem),
+                                                  DIRTY_MEMORY_VGA);
+
     for (y = 0; y < ts->height; page += TARGET_PAGE_SIZE,
             page24 += TARGET_PAGE_SIZE, cpage += TARGET_PAGE_SIZE) {
-        if (tcx24_check_dirty(ts, page, page24, cpage)) {
+        if (tcx24_check_dirty(ts, snap, page, page24, cpage)) {
             if (y_start < 0)
                 y_start = y;
-            if (page < page_min)
-                page_min = page;
-            if (page > page_max)
-                page_max = page;
             tcx24_draw_line32(ts, d, s, ts->width, cptr, s24);
             if (y >= ts->cursy && y < ts->cursy+32 && ts->cursx < ts->width) {
                 tcx_draw_cursor32(ts, d, y, ts->width);
@@ -521,10 +497,7 @@ static void tcx24_update_display(void *opaque)
         dpy_gfx_update(ts->con, 0, y_start,
                        ts->width, y - y_start);
     }
-    /* reset modified pages */
-    if (page_max >= page_min) {
-        tcx24_reset_dirty(ts, page_min, page_max, page24, cpage);
-    }
+    g_free(snap);
 }
 
 static void tcx_invalidate_display(void *opaque)
-- 
2.9.3