framebuffer: set DIRTY_MEMORY_VGA on RAM that is used for the framebuffer

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.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 42 insertions, 2 deletions

diff --git a/hw/display/framebuffer.h b/hw/display/framebuffer.h
index 6eae035b7d..38fa0dcec6 100644
--- a/hw/display/framebuffer.h
+++ b/hw/display/framebuffer.h
@@ -7,10 +7,50 @@
 
 typedef void (*drawfn)(void *, uint8_t *, const uint8_t *, int, int);
 
+/* framebuffer_update_memory_section: Update framebuffer
+ * #MemoryRegionSection, for example if the framebuffer is switched to
+ * a different memory area.
+ *
+ * @mem_section: Output #MemoryRegionSection, to be passed to
+ * framebuffer_update_display().
+ * @root: #MemoryRegion within which the framebuffer lies
+ * @base: Base address of the framebuffer within @root.
+ * @rows: Height of the screen.
+ * @src_width: Number of bytes in framebuffer memory between two rows.
+ */
+void framebuffer_update_memory_section(
+    MemoryRegionSection *mem_section,
+    MemoryRegion *root,
+    hwaddr base,
+    unsigned rows,
+    unsigned src_width);
+
+/* framebuffer_update_display: Draw the framebuffer on a surface.
+ *
+ * @ds: #DisplaySurface to draw to.
+ * @mem_section: #MemoryRegionSection provided by
+ * framebuffer_update_memory_section().
+ * @cols: Width the screen.
+ * @rows: Height of the screen.
+ * @src_width: Number of bytes in framebuffer memory between two rows.
+ * @dest_row_pitch: Number of bytes in the surface data between two rows.
+ * Negative if the framebuffer is stored in the opposite order (e.g.
+ * bottom-to-top) compared to the framebuffer.
+ * @dest_col_pitch: Number of bytes in the surface data between two pixels.
+ * Negative if the framebuffer is stored in the opposite order (e.g.
+ * right-to-left) compared to the framebuffer.
+ * @invalidate: True if the function should redraw the whole screen
+ * without checking the DIRTY_MEMORY_VGA dirty bitmap.
+ * @fn: Drawing function to be called for each row that has to be drawn.
+ * @opaque: Opaque pointer passed to @fn.
+ * @first_row: Pointer to an integer, receives the number of the first row
+ * that was drawn (either the first dirty row, or 0 if @invalidate is true).
+ * @last_row: Pointer to an integer, receives the number of the last row that
+ * was drawn (either the last dirty row, or @rows-1 if @invalidate is true).
+ */
 void framebuffer_update_display(
     DisplaySurface *ds,
-    MemoryRegion *address_space,
-    hwaddr base,
+    MemoryRegionSection *mem_section,
     int cols,
     int rows,
     int src_width,