Re: [virtio] [PATCH] ccw: split descriptor/available/used rings

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Tue, 8 Oct 2013 15:39:25 +0200
Cornelia Huck <cornelia.huck@de.ibm.com> wrote:

> On Tue, 8 Oct 2013 16:07:18 +0300
> "Michael S. Tsirkin" <mst@redhat.com> wrote:

> > If we want drivers to do something we really must write it
> > explicitly.
> > 
> 

OK, here's what I've got:

commit 5a36ad2c5826ccf777d12b2183efc265c51015b0
Author: Cornelia Huck <cornelia.huck@de.ibm.com>
Date:   Tue Oct 8 15:49:36 2013 +0200

    virtio-ccw: clarify sense id operation
    
    Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

diff --git a/virtio-v1.0-wd01-part1-specification.txt b/virtio-v1.0-wd01-part1-specification.txt
index d1b15c6..4eb770e 100644
--- a/virtio-v1.0-wd01-part1-specification.txt
+++ b/virtio-v1.0-wd01-part1-specification.txt
@@ -1515,6 +1515,28 @@ normal channel subsystem device discovery (usually a STORE
 SUBCHANNEL loop) and answers to the basic channel commands, most
 importantly SENSE ID.
 
+For a virtio-ccw proxy device, SENSE ID will return the following
+information:
+
+------------------------------------------------------
+| Bytes | Contents                                   |
+|-------|--------------------------------------------|
+| 0     | reserved              | 0xff               |
+|-------|-----------------------|--------------------|
+| 1-2   | control unit type     | 0x3832             |
+|-------|-----------------------|--------------------|
+| 3     | control unit model    | <virtio device id> |
+|-------|-----------------------|--------------------|
+| 4-5   | device type           | zeroes (unset)     |
+|-------|-----------------------|--------------------|
+| 6     | device model          | zeroes (unset)     |
+|-------|-----------------------|--------------------|
+| 7-255 | extended SenseId data | zeroes (unset)     |
+------------------------------------------------------
+
+A driver for virtio-ccw devices MUST check for a control unit
+type of 0x3832 and MUST ignore the device type and model.
+
 In addition to the basic channel commands, virtio-ccw defines a
 set of channel commands related to configuration and operation of
 virtio: