[Qemu-devel] [PATCH] virtio spec: add virtio-blk max sectors feature

[Avishay Traeger1]

I previously submitted a patch to have the guest virtio-blk driver get the
value for the maximum I/O size from the host bdrv, rather than assume that
there is no limit.  Avi requested that I first patch the virtio spec
(http://ozlabs.org/~rusty/virtio-spec/).  Below is that patch.

Please CC me on replies, as I am not subscribed.

Thank you,
Avishay

Signed-off-by: Avishay Traeger <address@hidden>

--- virtio-spec-0.8.2.lyx     2009-11-30 16:34:16.000000000 +0200
+++ virtio-spec-0.8.2-mod.lyx 2009-12-01 16:04:36.000000000 +0200
@@ -3999,6 +3999,20 @@
 \end_inset

 .
+\change_inserted 0 1259672174
+
+\end_layout
+
+\begin_layout Description
+
+\change_inserted 0 1259672252
+VIRTIO_BLK_F_SECTOR_MAX
+\begin_inset space ~
+\end_inset
+
+(10) Maximum sectors in an I/O.
+\change_unchanged
+
 \end_layout

 \end_deeper
@@ -4068,6 +4082,17 @@
 \begin_layout Plain Layout

      u32 blk_size;
+\change_inserted 0 1259672274
+
+\end_layout
+
+\begin_layout Plain Layout
+
+\change_inserted 0 1259672305
+
+     u32 sectors_max;
+\change_unchanged
+
 \end_layout

 \begin_layout Plain Layout
@@ -4107,6 +4132,18 @@
 \begin_layout Enumerate
 If the VIRTIO_BLK_F_RO feature is set by the device, any write requests
  will fail.
+\change_inserted 0 1259672345
+
+\end_layout
+
+\begin_layout Enumerate
+
+\change_inserted 0 1259672454
+If the VIRTIO_BLK_F_SECTOR_MAX feature is negotiated, the sectors_max
field
+ should be read to determine the maximum I/O size for the driver to use.
+ No requests should be submitted which go beyond this limit.
+\change_unchanged
+
 \end_layout

 \begin_layout Section*