[Qemu-devel] [PATCH for-2.3] softmmu: clarify meaning of TLB_NOTDIRTY bit

[Stefan Hajnoczi]

It wasn't obvious to me why the TLB entries should cache the memory
dirty bitmap state.

Signed-off-by: Stefan Hajnoczi <address@hidden>
---
 include/exec/cpu-all.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index c085804..e71e47e 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -329,7 +329,8 @@ extern RAMList ram_list;
 /* Zero if TLB entry is valid.  */
 #define TLB_INVALID_MASK   (1 << 3)
 /* Set if TLB entry references a clean RAM page.  The iotlb entry will
-   contain the page physical address.  */
+   contain the page physical address.  Forces us to take the slow path so pages
+   get marked dirty, whereas the fast path does not mark pages dirty.  */
 #define TLB_NOTDIRTY    (1 << 4)
 /* Set if TLB entry is an IO callback.  */
 #define TLB_MMIO        (1 << 5)
-- 
2.1.0