[Qemu-devel] [PATCH 0/2] cg3/tcx: make display updates thread safe

[Qemu-devel] [PATCH 0/2] cg3/tcx: make display updates thread safe

[Mark Cave-Ayland]

Now the previous fixes/cleanups have been applied, it is a fairly trivial
exercise to make cg3/tcx display updates thread safe.

Gerd, do you want to take these patches via your vga queue?

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

Mark Cave-Ayland (2):
  cg3: make display updates thread safe
  tcx: make display updates thread safe

 hw/display/cg3.c |   41 ++++++++++++++++----------------
 hw/display/tcx.c |   68 +++++++++++++++++++-----------------------------------
 2 files changed, 45 insertions(+), 64 deletions(-)

-- 
1.7.10.4

[Qemu-devel] [PATCH 1/2] cg3: make display updates thread safe

[Mark Cave-Ayland]

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
---
 hw/display/cg3.c |   41 +++++++++++++++++++++--------------------
 1 file changed, 21 insertions(+), 20 deletions(-)

diff --git a/hw/display/cg3.c b/hw/display/cg3.c
index 7ef8a96..1de15a1 100644
--- a/hw/display/cg3.c
+++ b/hw/display/cg3.c
@@ -94,7 +94,8 @@ static void cg3_update_display(void *opaque)
     uint32_t dval;
     int x, y, y_start;
     unsigned int width, height;
-    ram_addr_t page, page_min, page_max;
+    ram_addr_t page;
+    DirtyBitmapSnapshot *snap = NULL;
 
     if (surface_bits_per_pixel(surface) != 32) {
         return;
@@ -103,29 +104,32 @@ static void cg3_update_display(void *opaque)
     height = s->height;
 
     y_start = -1;
-    page_min = -1;
-    page_max = 0;
-    page = 0;
     pix = memory_region_get_ram_ptr(&s->vram_mem);
     data = (uint32_t *)surface_data(surface);
 
-    memory_region_sync_dirty_bitmap(&s->vram_mem);
+    if (!s->full_update) {
+        memory_region_sync_dirty_bitmap(&s->vram_mem);
+        snap = memory_region_snapshot_and_clear_dirty(&s->vram_mem, 0x0,
+                                              memory_region_size(&s->vram_mem),
+                                              DIRTY_MEMORY_VGA);
+    }
+
     for (y = 0; y < height; y++) {
-        int update = s->full_update;
+        int update;
 
         page = (ram_addr_t)y * width;
-        update |= memory_region_get_dirty(&s->vram_mem, page, width,
-                                          DIRTY_MEMORY_VGA);
+
+        if (s->full_update) {
+            update = 1;
+        } else {
+            update = memory_region_snapshot_get_dirty(&s->vram_mem, snap, page,
+                                                      width);
+        }
+
         if (update) {
             if (y_start < 0) {
                 y_start = y;
             }
-            if (page < page_min) {
-                page_min = page;
-            }
-            if (page > page_max) {
-                page_max = page;
-            }
 
             for (x = 0; x < width; x++) {
                 dval = *pix++;
@@ -134,7 +138,7 @@ static void cg3_update_display(void *opaque)
             }
         } else {
             if (y_start >= 0) {
-                dpy_gfx_update(s->con, 0, y_start, s->width, y - y_start);
+                dpy_gfx_update(s->con, 0, y_start, width, y - y_start);
                 y_start = -1;
             }
             pix += width;
@@ -143,17 +147,14 @@ static void cg3_update_display(void *opaque)
     }
     s->full_update = 0;
     if (y_start >= 0) {
-        dpy_gfx_update(s->con, 0, y_start, s->width, y - y_start);
-    }
-    if (page_max >= page_min) {
-        memory_region_reset_dirty(&s->vram_mem,
-                              page_min, page_max - page_min, DIRTY_MEMORY_VGA);
+        dpy_gfx_update(s->con, 0, y_start, width, y - y_start);
     }
     /* vsync interrupt? */
     if (s->regs[0] & CG3_CR_ENABLE_INTS) {
         s->regs[1] |= CG3_SR_PENDING_INT;
         qemu_irq_raise(s->irq);
     }
+    g_free(snap);
 }
 
 static void cg3_invalidate_display(void *opaque)
-- 
1.7.10.4

[Qemu-devel] [PATCH 2/2] tcx: make display updates thread safe

[Mark Cave-Ayland]

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
---
 hw/display/tcx.c |   68 +++++++++++++++++++-----------------------------------
 1 file changed, 24 insertions(+), 44 deletions(-)

diff --git a/hw/display/tcx.c b/hw/display/tcx.c
index 0e66dcd..6593c1d 100644
--- a/hw/display/tcx.c
+++ b/hw/display/tcx.c
@@ -104,36 +104,23 @@ static void tcx_set_dirty(TCXState *s, ram_addr_t addr, int len)
     }
 }
 
-static int tcx_check_dirty(TCXState *s, ram_addr_t addr, int len)
+static int tcx_check_dirty(TCXState *s, DirtyBitmapSnapshot *snap,
+                           ram_addr_t addr, int len)
 {
     int ret;
 
-    ret = memory_region_get_dirty(&s->vram_mem, addr, len, DIRTY_MEMORY_VGA);
+    ret = memory_region_snapshot_get_dirty(&s->vram_mem, snap, addr, len);
 
     if (s->depth == 24) {
-        ret |= memory_region_get_dirty(&s->vram_mem,
-                                       s->vram24_offset + addr * 4, len * 4,
-                                       DIRTY_MEMORY_VGA);
-        ret |= memory_region_get_dirty(&s->vram_mem,
-                                       s->cplane_offset + addr * 4, len * 4,
-                                       DIRTY_MEMORY_VGA);
+        ret |= memory_region_snapshot_get_dirty(&s->vram_mem, snap,
+                                       s->vram24_offset + addr * 4, len * 4);
+        ret |= memory_region_snapshot_get_dirty(&s->vram_mem, snap,
+                                       s->cplane_offset + addr * 4, len * 4);
     }
 
     return ret;
 }
 
-static void tcx_reset_dirty(TCXState *s, ram_addr_t addr, int len)
-{
-    memory_region_reset_dirty(&s->vram_mem, addr, len, DIRTY_MEMORY_VGA);
-
-    if (s->depth == 24) {
-        memory_region_reset_dirty(&s->vram_mem, s->vram24_offset + addr * 4,
-                                  len * 4, DIRTY_MEMORY_VGA);
-        memory_region_reset_dirty(&s->vram_mem, s->cplane_offset + addr * 4,
-                                  len * 4, DIRTY_MEMORY_VGA);
-    }
-}
-
 static void update_palette_entries(TCXState *s, int start, int end)
 {
     DisplaySurface *surface = qemu_console_surface(s->con);
@@ -233,7 +220,8 @@ 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;
 
@@ -243,22 +231,20 @@ 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);
     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; y++, page += ds) {
-        if (tcx_check_dirty(ts, page, ds)) {
+        if (tcx_check_dirty(ts, snap, page, ds)) {
             if (y_start < 0)
                 y_start = y;
-            if (page < page_min)
-                page_min = page;
-            if (page > page_max)
-                page_max = page;
 
             tcx_draw_line32(ts, d, s, ts->width);
             if (y >= ts->cursy && y < ts->cursy + 32 && ts->cursx < ts->width) {
@@ -280,17 +266,15 @@ 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) {
-        tcx_reset_dirty(ts, page_min, page_max - page_min);
-    }
+    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;
+    ram_addr_t page;
+    DirtyBitmapSnapshot *snap = NULL;
     int y, y_start, dd, ds;
     uint8_t *d, *s;
     uint32_t *cptr, *s24;
@@ -301,8 +285,6 @@ static void tcx24_update_display(void *opaque)
 
     page = 0;
     y_start = -1;
-    page_min = -1;
-    page_max = 0;
     d = surface_data(surface);
     s = ts->vram;
     s24 = ts->vram24;
@@ -311,14 +293,15 @@ 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; y++, page += ds) {
-        if (tcx_check_dirty(ts, page, ds)) {
+        if (tcx_check_dirty(ts, snap, page, ds)) {
             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);
@@ -341,10 +324,7 @@ 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) {
-        tcx_reset_dirty(ts, page_min, page_max - page_min);
-    }
+    g_free(snap);
 }
 
 static void tcx_invalidate_display(void *opaque)
-- 
1.7.10.4

Re: [Qemu-devel] [PATCH 0/2] cg3/tcx: make display updates thread safe

[Gerd Hoffmann]

On Mi, 2017-05-10 at 21:52 +0100, Mark Cave-Ayland wrote:
> Now the previous fixes/cleanups have been applied, it is a fairly trivial
> exercise to make cg3/tcx display updates thread safe.
> 
> Gerd, do you want to take these patches via your vga queue?

Can do that, I have some more pending patches for that anyway.

cheers,
  Gerd