[Qemu-devel] [PATCH 4/6] memory: find dirty range

[Blue Swirl]

Instead of each target knowing or guessing the guest page size,
iterate through the dirty ranges.

Signed-off-by: Blue Swirl <address@hidden>
---
 cpu-all.h |   30 ++++++++++++++++++++++++++++++
 hw/tcx.c  |   54 ++++++++++++++++++++++--------------------------------
 hw/vga.c  |   16 +++++++---------
 memory.c  |   16 ++++++++++++++++
 memory.h  |   24 ++++++++++++++++++++++++
 5 files changed, 99 insertions(+), 41 deletions(-)

diff --git a/cpu-all.h b/cpu-all.h
index 0cb62ca..a5c6670 100644
--- a/cpu-all.h
+++ b/cpu-all.h
@@ -574,6 +574,36 @@ int cpu_physical_memory_set_dirty_tracking(int enable);

 int cpu_physical_memory_get_dirty_tracking(void);

+static inline void cpu_physical_memory_range_find_dirty(ram_addr_t start,
+                                                        ram_addr_t end,
+                                                        ram_addr_t *pstart,
+                                                        ram_addr_t *pend,
+                                                        int flags)
+{
+    ram_addr_t idx;
+
+    start >>= TARGET_PAGE_BITS;
+    end += TARGET_PAGE_SIZE - 1;
+    end >>= TARGET_PAGE_BITS;
+
+    for (idx = start; idx < end; idx++) {
+        if (ram_list.phys_dirty[idx] & flags) {
+            *pstart = idx << TARGET_PAGE_BITS;
+            for (; idx < end; idx++) {
+                if (!(ram_list.phys_dirty[idx] & flags)) {
+                    *pend = (idx << TARGET_PAGE_BITS) - 1;
+                    return;
+                }
+            }
+            *pend = (end << TARGET_PAGE_BITS) - 1;
+            return;
+        }
+    }
+    /* everything pristine */
+    *pstart = (end << TARGET_PAGE_BITS) - 1;
+    *pend = (end << TARGET_PAGE_BITS) - 1;
+}
+
 int cpu_physical_sync_dirty_bitmap(target_phys_addr_t start_addr,
                                    target_phys_addr_t end_addr);

diff --git a/hw/tcx.c b/hw/tcx.c
index fd45ce8..d031cbd 100644
--- a/hw/tcx.c
+++ b/hw/tcx.c
@@ -212,7 +212,7 @@ static inline void reset_dirty(TCXState *ts,
ram_addr_t page_min,
 static void tcx_update_display(void *opaque)
 {
     TCXState *ts = opaque;
-    ram_addr_t page, page_min, page_max;
+    ram_addr_t page, page_min, page_max, p;
     int y, y_start, dd, ds;
     uint8_t *d, *s;
     void (*f)(TCXState *s1, uint8_t *dst, const uint8_t *src, int width);
@@ -244,37 +244,28 @@ static void tcx_update_display(void *opaque)
         return;
     }

-    for(y = 0; y < ts->height; y += 4, page += TARGET_PAGE_SIZE) {
-        if (memory_region_get_dirty(&ts->vram_mem, page, DIRTY_MEMORY_VGA)) {
-            if (y_start < 0)
-                y_start = y;
-            if (page < page_min)
-                page_min = page;
-            if (page > page_max)
-                page_max = page;
-            f(ts, d, s, ts->width);
-            d += dd;
-            s += ds;
-            f(ts, d, s, ts->width);
-            d += dd;
-            s += ds;
-            f(ts, d, s, ts->width);
-            d += dd;
-            s += ds;
-            f(ts, d, s, ts->width);
-            d += dd;
-            s += ds;
-        } else {
-            if (y_start >= 0) {
-                /* flush to display */
-                dpy_update(ts->ds, 0, y_start,
-                           ts->width, y - y_start);
-                y_start = -1;
-            }
-            d += dd * 4;
-            s += ds * 4;
+    assert(MAXX == 1024);
+    y = 0;
+    for (p = 0; p < MAXX * MAXY;)  {
+        target_phys_addr_t dirty_start, dirty_end;
+
+        memory_region_find_dirty(&ts->vram_mem, p, MAXX * MAXY, &dirty_start,
+                                 &dirty_end, DIRTY_MEMORY_VGA);
+        if (dirty_start == MAXX * MAXY - 1) {
+            break;
+        }
+        page = dirty_start;
+        f(ts, d + (page >> 10) * dd, s + page, dirty_end - dirty_start);
+        if (y_start < 0) {
+            page_min = dirty_start;
+            /* divide by MAXX */
+            y_start = page_min >> 10;
         }
+        page_max = dirty_end;
+        y = page_max >> 10;
+        p = dirty_end + 1;
     }
+
     if (y_start >= 0) {
         /* flush to display */
         dpy_update(ts->ds, 0, y_start,
@@ -282,8 +273,7 @@ static void tcx_update_display(void *opaque)
     }
     /* reset modified pages */
     if (page_max >= page_min) {
-        memory_region_reset_dirty(&ts->vram_mem,
-                                  page_min, page_max + TARGET_PAGE_SIZE,
+        memory_region_reset_dirty(&ts->vram_mem, page_min, page_max,
                                   DIRTY_MEMORY_VGA);
     }
 }
diff --git a/hw/vga.c b/hw/vga.c
index 85176a6..16c94b6 100644
--- a/hw/vga.c
+++ b/hw/vga.c
@@ -1731,6 +1731,8 @@ static void vga_draw_graphic(VGACommonState *s,
int full_update)
     linesize = ds_get_linesize(s->ds);
     y1 = 0;
     for(y = 0; y < height; y++) {
+        target_phys_addr_t dirty_start, dirty_end;
+
         addr = addr1;
         if (!(s->cr[0x17] & 1)) {
             int shift;
@@ -1741,17 +1743,13 @@ static void vga_draw_graphic(VGACommonState
*s, int full_update)
         if (!(s->cr[0x17] & 2)) {
             addr = (addr & ~0x8000) | ((y1 & 2) << 14);
         }
+        memory_region_find_dirty(&s->vram, addr, addr + bwidth - 1,
+                                 &dirty_start, &dirty_end, DIRTY_MEMORY_VGA);
+        if (dirty_start < addr + bwidth - 1) {
+            update = 1;
+        }
         page0 = addr & TARGET_PAGE_MASK;
         page1 = (addr + bwidth - 1) & TARGET_PAGE_MASK;
-        update = full_update |
-            memory_region_get_dirty(&s->vram, page0, DIRTY_MEMORY_VGA) |
-            memory_region_get_dirty(&s->vram, page1, DIRTY_MEMORY_VGA);
-        if ((page1 - page0) > TARGET_PAGE_SIZE) {
-            /* if wide line, can use another page */
-            update |= memory_region_get_dirty(&s->vram,
-                                              page0 + TARGET_PAGE_SIZE,
-                                              DIRTY_MEMORY_VGA);
-        }
         /* explicit invalidation for the hardware cursor */
         update |= (s->invalidated_y_table[y >> 5] >> (y & 0x1f)) & 1;
         if (update) {
diff --git a/memory.c b/memory.c
index 71600d0..af684fa 100644
--- a/memory.c
+++ b/memory.c
@@ -1068,6 +1068,22 @@ bool memory_region_get_dirty(MemoryRegion *mr,
target_phys_addr_t addr,
     return cpu_physical_memory_get_dirty(mr->ram_addr + addr, 1 << client);
 }

+void memory_region_find_dirty(MemoryRegion *mr, target_phys_addr_t start,
+                              target_phys_addr_t end,
+                              target_phys_addr_t *pstart,
+                              target_phys_addr_t *pend,
+                              unsigned client)
+{
+    ram_addr_t dstart, dend;
+
+    assert(mr->terminates);
+    cpu_physical_memory_range_find_dirty(mr->ram_addr + start,
+                                         mr->ram_addr + end, &dstart, &dend,
+                                         1 << client);
+    *pstart = dstart - mr->ram_addr;
+    *pend = dend - mr->ram_addr;
+}
+
 void memory_region_set_dirty(MemoryRegion *mr, target_phys_addr_t addr,
                              target_phys_addr_t size)
 {
diff --git a/memory.h b/memory.h
index 1f8b5a5..ace2708 100644
--- a/memory.h
+++ b/memory.h
@@ -314,6 +314,30 @@ bool memory_region_get_dirty(MemoryRegion *mr,
target_phys_addr_t addr,
                              unsigned client);

 /**
+ * memory_region_find_dirty: Find dirty ranges in a memory range for a
+ *                           specified client.
+ *
+ * Returns lowest contiguous dirty memory range within the specified
memory range.
+ * Dirty logging must be enabled.
+ *
+ * @mr: the memory region being queried.
+ * @start: the start address (relative to the start of the region) of the
+ * region being searched.
+ * @end: the end address (relative to the start of the region) of the
+ * region being searched.
+ * address@hidden: the returned start address (relative to the start of the 
region)
+ * of the lowest contiguous dirty range found, or @end if not found.
+ * address@hidden: the returned end address (relative to the start of the 
region)
+ * of the lowest contiguous dirty range found.
+ * @client: the user of the logging information; %DIRTY_MEMORY_MIGRATION or
+ *          %DIRTY_MEMORY_VGA.
+ */
+void memory_region_find_dirty(MemoryRegion *mr, target_phys_addr_t start,
+                              target_phys_addr_t end,
+                              target_phys_addr_t *pstart,
+                              target_phys_addr_t *pend,
+                              unsigned client);
+/**
  * memory_region_set_dirty: Mark a page as dirty in a memory region.
  *
  * Marks a page as dirty, after it has been dirtied outside guest code.
-- 
1.7.2.5