[Qemu-devel] [PATCH for-2.4 2/2] framebuffer: set DIRTY_MEMORY_VGA on RAM that is used for the framebuffer

[Paolo Bonzini <pbonzini@redhat.com>]

The MemoryRegionSection contains enough information to access the
RAM region underlying the framebuffer, and can be cached inside the
display device.

By doing this, the new framebuffer_update_memory_section function can
enable dirty memory logging on the relevant RAM region.  The function
must be called whenever the stride or base of the framebuffer changes;
a simple way to cover these cases is to call it on every full frame
invalidation, which is a rare case.

framebuffer_update_display now works entirely on a MemoryRegionSection,
without going through cpu_physical_memory_map/unmap.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
        only tested with vexpress (pl110)

 hw/display/framebuffer.c     | 75 ++++++++++++++++++++++++--------------------
 hw/display/framebuffer.h     | 10 ++++--
 hw/display/milkymist-vgafb.c | 15 +++++++--
 hw/display/omap_lcdc.c       | 12 +++++--
 hw/display/pl110.c           | 13 ++++++--
 hw/display/pxa2xx_lcd.c      | 29 ++++++++++++-----
 6 files changed, 103 insertions(+), 51 deletions(-)

diff --git a/hw/display/framebuffer.c b/hw/display/framebuffer.c
index 2cabced..7f075ce 100644
--- a/hw/display/framebuffer.c
+++ b/hw/display/framebuffer.c
@@ -21,12 +21,40 @@
 #include "ui/console.h"
 #include "framebuffer.h"
 
+void framebuffer_update_memory_section(
+    MemoryRegionSection *mem_section,
+    MemoryRegion *root,
+    hwaddr base,
+    unsigned rows,
+    unsigned src_width)
+{
+    hwaddr src_len = (hwaddr)rows * src_width;
+
+    if (mem_section->mr) {
+        memory_region_set_log(mem_section->mr, false, DIRTY_MEMORY_VGA);
+        memory_region_unref(mem_section->mr);
+        mem_section->mr = NULL;
+    }
+
+    *mem_section = memory_region_find(root, base, src_len);
+    if (!mem_section->mr) {
+        return;
+    }
+
+    if (int128_get64(mem_section->size) < src_len ||
+            !memory_region_is_ram(mem_section->mr)) {
+        memory_region_unref(mem_section->mr);
+        mem_section->mr = NULL;
+        return;
+    }
+
+    memory_region_set_log(mem_section->mr, true, DIRTY_MEMORY_VGA);
+}
+
 /* Render an image from a shared memory framebuffer.  */
-   
 void framebuffer_update_display(
     DisplaySurface *ds,
-    MemoryRegion *address_space,
-    hwaddr base,
+    MemoryRegionSection *mem_section,
     int cols, /* Width in pixels.  */
     int rows, /* Height in pixels.  */
     int src_width, /* Length of source line, in bytes.  */
@@ -41,51 +69,33 @@ void framebuffer_update_display(
     hwaddr src_len;
     uint8_t *dest;
     uint8_t *src;
-    uint8_t *src_base;
     int first, last = 0;
     int dirty;
     int i;
     ram_addr_t addr;
-    MemoryRegionSection mem_section;
     MemoryRegion *mem;
 
     i = *first_row;
     *first_row = -1;
     src_len = src_width * rows;
 
-    mem_section = memory_region_find(address_space, base, src_len);
-    mem = mem_section.mr;
-    if (int128_get64(mem_section.size) != src_len ||
-            !memory_region_is_ram(mem_section.mr)) {
-        goto out;
+    mem = mem_section->mr;
+    if (!mem) {
+        return;
     }
-    assert(mem);
-    assert(mem_section.offset_within_address_space == base);
-
     memory_region_sync_dirty_bitmap(mem);
-    if (!memory_region_is_logging(mem, DIRTY_MEMORY_VGA)) {
-        invalidate = true;
-    }
 
-    src_base = cpu_physical_memory_map(base, &src_len, 0);
-    /* If we can't map the framebuffer then bail.  We could try harder,
-       but it's not really worth it as dirty flag tracking will probably
-       already have failed above.  */
-    if (!src_base)
-        goto out;
-    if (src_len != src_width * rows) {
-        cpu_physical_memory_unmap(src_base, src_len, 0, 0);
-        goto out;
-    }
-    src = src_base;
+    addr = mem_section->offset_within_region;
+    src = memory_region_get_ram_ptr(mem) + addr;
+
     dest = surface_data(ds);
-    if (dest_col_pitch < 0)
+    if (dest_col_pitch < 0) {
         dest -= dest_col_pitch * (cols - 1);
+    }
     if (dest_row_pitch < 0) {
         dest -= dest_row_pitch * (rows - 1);
     }
     first = -1;
-    addr = mem_section.offset_within_region;
 
     addr += i * src_width;
     src += i * src_width;
@@ -104,14 +114,11 @@ void framebuffer_update_display(
         src += src_width;
         dest += dest_row_pitch;
     }
-    cpu_physical_memory_unmap(src_base, src_len, 0, 0);
     if (first < 0) {
-        goto out;
+        return;
     }
-    memory_region_reset_dirty(mem, mem_section.offset_within_region, src_len,
+    memory_region_reset_dirty(mem, mem_section->offset_within_region, src_len,
                               DIRTY_MEMORY_VGA);
     *first_row = first;
     *last_row = last;
-out:
-    memory_region_unref(mem);
 }
diff --git a/hw/display/framebuffer.h b/hw/display/framebuffer.h
index 6eae035..e735bb7 100644
--- a/hw/display/framebuffer.h
+++ b/hw/display/framebuffer.h
@@ -7,10 +7,16 @@
 
 typedef void (*drawfn)(void *, uint8_t *, const uint8_t *, int, int);
 
+void framebuffer_update_memory_section(
+    MemoryRegionSection *mem_section,
+    MemoryRegion *root,
+    hwaddr base,
+    unsigned rows,
+    unsigned src_width);
+
 void framebuffer_update_display(
     DisplaySurface *ds,
-    MemoryRegion *address_space,
-    hwaddr base,
+    MemoryRegionSection *mem_section,
     int cols,
     int rows,
     int src_width,
diff --git a/hw/display/milkymist-vgafb.c b/hw/display/milkymist-vgafb.c
index 9b35e76..ab3074f 100644
--- a/hw/display/milkymist-vgafb.c
+++ b/hw/display/milkymist-vgafb.c
@@ -71,6 +71,7 @@ struct MilkymistVgafbState {
     SysBusDevice parent_obj;
 
     MemoryRegion regs_region;
+    MemoryRegionSection fbsection;
     QemuConsole *con;
 
     int invalidate;
@@ -91,6 +92,7 @@ static void vgafb_update_display(void *opaque)
     MilkymistVgafbState *s = opaque;
     SysBusDevice *sbd;
     DisplaySurface *surface = qemu_console_surface(s->con);
+    int src_width;
     int first = 0;
     int last = 0;
     drawfn fn;
@@ -129,11 +131,18 @@ static void vgafb_update_display(void *opaque)
         break;
     }
 
-    framebuffer_update_display(surface, sysbus_address_space(sbd),
-                               s->regs[R_BASEADDRESS] + s->fb_offset,
+    src_width = s->regs[R_HRES] * 2;
+    if (s->invalidate) {
+        framebuffer_update_memory_section(&s->fbsection,
+                                          sysbus_address_space(sbd),
+                                          s->regs[R_BASEADDRESS] + s->fb_offset,
+                                          s->regs[R_VRES], src_width);
+    }
+
+    framebuffer_update_display(surface, &s->fbsection,
                                s->regs[R_HRES],
                                s->regs[R_VRES],
-                               s->regs[R_HRES] * 2,
+                               src_width,
                                dest_width,
                                0,
                                s->invalidate,
diff --git a/hw/display/omap_lcdc.c b/hw/display/omap_lcdc.c
index fda81ba..a7c6cd7 100644
--- a/hw/display/omap_lcdc.c
+++ b/hw/display/omap_lcdc.c
@@ -25,6 +25,7 @@
 struct omap_lcd_panel_s {
     MemoryRegion *sysmem;
     MemoryRegion iomem;
+    MemoryRegionSection fbsection;
     qemu_irq irq;
     QemuConsole *con;
 
@@ -215,12 +216,19 @@ static void omap_update_display(void *opaque)
 
     step = width * bpp >> 3;
     linesize = surface_stride(surface);
-    framebuffer_update_display(surface, omap_lcd->sysmem,
-                               frame_base, width, height,
+    if (omap_lcd->invalidate) {
+        framebuffer_update_memory_section(&omap_lcd->fbsection,
+                                          omap_lcd->sysmem, frame_base,
+                                          height, step);
+    }
+
+    framebuffer_update_display(surface, &omap_lcd->fbsection,
+                               width, height,
                                step, linesize, 0,
                                omap_lcd->invalidate,
                                draw_line, omap_lcd->palette,
                                &first, &last);
+
     if (first >= 0) {
         dpy_gfx_update(omap_lcd->con, 0, first, width, last - first + 1);
     }
diff --git a/hw/display/pl110.c b/hw/display/pl110.c
index c574cf1..ef1a7b1 100644
--- a/hw/display/pl110.c
+++ b/hw/display/pl110.c
@@ -46,6 +46,7 @@ typedef struct PL110State {
     SysBusDevice parent_obj;
 
     MemoryRegion iomem;
+    MemoryRegionSection fbsection;
     QemuConsole *con;
 
     int version;
@@ -238,12 +239,20 @@ static void pl110_update_display(void *opaque)
     }
     dest_width *= s->cols;
     first = 0;
-    framebuffer_update_display(surface, sysbus_address_space(sbd),
-                               s->upbase, s->cols, s->rows,
+    if (s->invalidate) {
+        framebuffer_update_memory_section(&s->fbsection,
+                                          sysbus_address_space(sbd),
+                                          s->upbase,
+                                          s->rows, src_width);
+    }
+
+    framebuffer_update_display(surface, &s->fbsection,
+                               s->cols, s->rows,
                                src_width, dest_width, 0,
                                s->invalidate,
                                fn, s->palette,
                                &first, &last);
+
     if (first >= 0) {
         dpy_gfx_update(s->con, 0, first, s->cols, last - first + 1);
     }
diff --git a/hw/display/pxa2xx_lcd.c b/hw/display/pxa2xx_lcd.c
index ac3c018..47dcd39 100644
--- a/hw/display/pxa2xx_lcd.c
+++ b/hw/display/pxa2xx_lcd.c
@@ -35,6 +35,7 @@ struct DMAChannel {
 struct PXA2xxLCDState {
     MemoryRegion *sysmem;
     MemoryRegion iomem;
+    MemoryRegionSection fbsection;
     qemu_irq irq;
     int irqlevel;
 
@@ -687,8 +688,11 @@ static void pxa2xx_lcdc_dma0_redraw_rot0(PXA2xxLCDState *s,
 
     dest_width = s->xres * s->dest_width;
     *miny = 0;
-    framebuffer_update_display(surface, s->sysmem,
-                               addr, s->xres, s->yres,
+    if (s->invalidated) {
+        framebuffer_update_memory_section(&s->fbsection, s->sysmem,
+                                          addr, src_width, s->yres);
+    }
+    framebuffer_update_display(surface, &s->fbsection, s->xres, s->yres,
                                src_width, dest_width, s->dest_width,
                                s->invalidated,
                                fn, s->dma_ch[0].palette, miny, maxy);
@@ -715,8 +719,11 @@ static void pxa2xx_lcdc_dma0_redraw_rot90(PXA2xxLCDState *s,
 
     dest_width = s->yres * s->dest_width;
     *miny = 0;
-    framebuffer_update_display(surface, s->sysmem,
-                               addr, s->xres, s->yres,
+    if (s->invalidated) {
+        framebuffer_update_memory_section(&s->fbsection, s->sysmem,
+                                          addr, src_width, s->yres);
+    }
+    framebuffer_update_display(surface, &s->fbsection, s->xres, s->yres,
                                src_width, s->dest_width, -dest_width,
                                s->invalidated,
                                fn, s->dma_ch[0].palette,
@@ -747,8 +754,11 @@ static void pxa2xx_lcdc_dma0_redraw_rot180(PXA2xxLCDState *s,
 
     dest_width = s->xres * s->dest_width;
     *miny = 0;
-    framebuffer_update_display(surface, s->sysmem,
-                               addr, s->xres, s->yres,
+    if (s->invalidated) {
+        framebuffer_update_memory_section(&s->fbsection, s->sysmem,
+                                          addr, src_width, s->yres);
+    }
+    framebuffer_update_display(surface, &s->fbsection, s->xres, s->yres,
                                src_width, -dest_width, -s->dest_width,
                                s->invalidated,
                                fn, s->dma_ch[0].palette, miny, maxy);
@@ -778,8 +788,11 @@ static void pxa2xx_lcdc_dma0_redraw_rot270(PXA2xxLCDState *s,
 
     dest_width = s->yres * s->dest_width;
     *miny = 0;
-    framebuffer_update_display(surface, s->sysmem,
-                               addr, s->xres, s->yres,
+    if (s->invalidated) {
+        framebuffer_update_memory_section(&s->fbsection, s->sysmem,
+                                          addr, src_width, s->yres);
+    }
+    framebuffer_update_display(surface, &s->fbsection, s->xres, s->yres,
                                src_width, -s->dest_width, dest_width,
                                s->invalidated,
                                fn, s->dma_ch[0].palette,
-- 
2.4.3