115 lines
4.3 KiB
Diff
115 lines
4.3 KiB
Diff
From 54b1106d9a24dadae42c4f4c25b4fa2560183f5b Mon Sep 17 00:00:00 2001
|
|
From: Gerd Hoffmann <kraxel@redhat.com>
|
|
Date: Fri, 21 Apr 2017 11:16:27 +0200
|
|
Subject: [PATCH 09/23] vga: make display updates thread safe.
|
|
|
|
The vga code clears the dirty bits *after* reading the framebuffer
|
|
memory. So if the guest framebuffer updates hits the race window
|
|
between vga reading the framebuffer and vga clearing the dirty bits
|
|
vga will miss that update
|
|
|
|
Fix it by using the new memory_region_copy_and_clear_dirty()
|
|
memory_region_copy_get_dirty() functions. That way we clear the
|
|
dirty bitmap before reading the framebuffer. Any guest display
|
|
updates happening in parallel will be properly tracked in the
|
|
dirty bitmap then and the next display refresh will pick them up.
|
|
|
|
Problem triggers with mttcg only. Before mttcg was merged tcg
|
|
never ran in parallel to vga emulation. Using kvm will hide the
|
|
problem too, due to qemu operating on a userspace copy of the
|
|
kernel's dirty bitmap.
|
|
|
|
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
|
|
Message-id: 20170421091632.30900-5-kraxel@redhat.com
|
|
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
|
|
---
|
|
hw/display/vga.c | 36 +++++++++++++++++-------------------
|
|
1 file changed, 17 insertions(+), 19 deletions(-)
|
|
|
|
diff --git a/hw/display/vga.c b/hw/display/vga.c
|
|
index 3991b88aac..b2516c8d21 100644
|
|
--- a/hw/display/vga.c
|
|
+++ b/hw/display/vga.c
|
|
@@ -1465,7 +1465,8 @@ static void vga_draw_graphic(VGACommonState *s, int full_update)
|
|
DisplaySurface *surface = qemu_console_surface(s->con);
|
|
int y1, y, update, linesize, y_start, double_scan, mask, depth;
|
|
int width, height, shift_control, line_offset, bwidth, bits;
|
|
- ram_addr_t page0, page1, page_min, page_max;
|
|
+ ram_addr_t page0, page1;
|
|
+ DirtyBitmapSnapshot *snap = NULL;
|
|
int disp_width, multi_scan, multi_run;
|
|
uint8_t *d;
|
|
uint32_t v, addr1, addr;
|
|
@@ -1480,9 +1481,6 @@ static void vga_draw_graphic(VGACommonState *s, int full_update)
|
|
|
|
full_update |= update_basic_params(s);
|
|
|
|
- if (!full_update)
|
|
- vga_sync_dirty_bitmap(s);
|
|
-
|
|
s->get_resolution(s, &width, &height);
|
|
disp_width = width;
|
|
|
|
@@ -1625,11 +1623,17 @@ static void vga_draw_graphic(VGACommonState *s, int full_update)
|
|
addr1 = (s->start_addr * 4);
|
|
bwidth = (width * bits + 7) / 8;
|
|
y_start = -1;
|
|
- page_min = -1;
|
|
- page_max = 0;
|
|
d = surface_data(surface);
|
|
linesize = surface_stride(surface);
|
|
y1 = 0;
|
|
+
|
|
+ if (!full_update) {
|
|
+ vga_sync_dirty_bitmap(s);
|
|
+ snap = memory_region_snapshot_and_clear_dirty(&s->vram, addr1,
|
|
+ bwidth * height,
|
|
+ DIRTY_MEMORY_VGA);
|
|
+ }
|
|
+
|
|
for(y = 0; y < height; y++) {
|
|
addr = addr1;
|
|
if (!(s->cr[VGA_CRTC_MODE] & 1)) {
|
|
@@ -1644,17 +1648,17 @@ static void vga_draw_graphic(VGACommonState *s, int full_update)
|
|
update = full_update;
|
|
page0 = addr;
|
|
page1 = addr + bwidth - 1;
|
|
- update |= memory_region_get_dirty(&s->vram, page0, page1 - page0,
|
|
- DIRTY_MEMORY_VGA);
|
|
+ if (full_update) {
|
|
+ update = 1;
|
|
+ } else {
|
|
+ update = memory_region_snapshot_get_dirty(&s->vram, snap,
|
|
+ page0, page1 - page0);
|
|
+ }
|
|
/* explicit invalidation for the hardware cursor (cirrus only) */
|
|
update |= vga_scanline_invalidated(s, y);
|
|
if (update) {
|
|
if (y_start < 0)
|
|
y_start = y;
|
|
- if (page0 < page_min)
|
|
- page_min = page0;
|
|
- if (page1 > page_max)
|
|
- page_max = page1;
|
|
if (!(is_buffer_shared(surface))) {
|
|
vga_draw_line(s, d, s->vram_ptr + addr, width);
|
|
if (s->cursor_draw_line)
|
|
@@ -1687,13 +1691,7 @@ static void vga_draw_graphic(VGACommonState *s, int full_update)
|
|
dpy_gfx_update(s->con, 0, y_start,
|
|
disp_width, y - y_start);
|
|
}
|
|
- /* reset modified pages */
|
|
- if (page_max >= page_min) {
|
|
- memory_region_reset_dirty(&s->vram,
|
|
- page_min,
|
|
- page_max - page_min,
|
|
- DIRTY_MEMORY_VGA);
|
|
- }
|
|
+ g_free(snap);
|
|
memset(s->invalidated_y_table, 0, sizeof(s->invalidated_y_table));
|
|
}
|
|
|
|
--
|
|
2.11.0
|
|
|