From: Stefan Hajnoczi <stefanha@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
"Andreas Färber" <afaerber@suse.de>,
"Stefan Hajnoczi" <stefanha@redhat.com>,
rth@twiddle.net
Subject: [Qemu-devel] [PATCH for-2.3] softmmu: clarify meaning of TLB_NOTDIRTY bit
Date: Wed, 26 Nov 2014 16:50:16 +0000 [thread overview]
Message-ID: <1417020616-21654-1-git-send-email-stefanha@redhat.com> (raw)
It wasn't obvious to me why the TLB entries should cache the memory
dirty bitmap state.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
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
reply other threads:[~2014-11-26 16:50 UTC|newest]
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