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Subject[PATCH] virtio-spec: clarify ro/rw bits and updating rule of virtio-net status field
This patch clarifies VIRTIO_NET_S_LINK_UP as a read-only bit and
VIRTIO_NET_S_ANNOUNCE as a read-writable bit. Also introduce the write 1 to
clear semantics for all read-writable bits of config status field. This could
help to reduce the config status field updating race between host and guest and
also simplify the implementation.

Signed-off-by: Jason Wang <>
virtio-0.9.4.lyx | 23 +++++++++++++++++++++--
1 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/virtio-0.9.4.lyx b/virtio-0.9.4.lyx
index 6c7bab1..614ab55 100644
--- a/virtio-0.9.4.lyx
+++ b/virtio-0.9.4.lyx
@@ -58,6 +58,7 @@
\html_be_strict false
\author -608949062 "Rusty Russell,,,"
\author 1531152142 "pbonzini"
+\author 2090695081 "jason"

@@ -4013,7 +4014,21 @@ layout Two configuration fields are currently defined.
The mac address field always exists (though is only valid if VIRTIO_NET_F_MAC
is set), and the status field only exists if VIRTIO_NET_F_STATUS is set.
Two bits are currently defined for the status field: VIRTIO_NET_S_LINK_UP
+\change_inserted 2090695081 1332220873
+\change_inserted 2090695081 1332220883
+ (read-writable)
+\change_inserted 2090695081 1332220901
+ Writing 1 to any read-writable bit of status filed would cause the bit
+ to be cleared.

\begin_inset listings
inline false
@@ -4915,7 +4930,11 @@ Processing this notification involves:

\begin_layout Enumerate
-Clearing VIRTIO_NET_S_ANNOUNCE bit in the status field.
+Clearing VIRTIO_NET_S_ANNOUNCE bit in the status field
+\change_inserted 2090695081 1332220849
+ (by writing 1 to VIRTIO_NET_S_ANNOUNCE bit)

\begin_layout Enumerate

 \ /
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