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, 41 insertions, 34 deletions

diff --git a/hw/display/framebuffer.c b/hw/display/framebuffer.c
index 2cabced208..7f075ce776 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);
 }