[libvirt] [PATCH v4 9/9] docs: Add vhost-scsi

[John Ferlan]

On 12/07/2016 08:16 PM, Jim Fehlig wrote:
> On 11/22/2016 02:16 PM, John Ferlan wrote:
>>
>>
>> On 11/21/2016 10:58 PM, Eric Farman wrote:
>>> Signed-off-by: Eric Farman <farman at linux.vnet.ibm.com>
>>> ---
>>>  docs/formatdomain.html.in | 24 ++++++++++++++++++++++++
>>>  1 file changed, 24 insertions(+)
>>>
>>
>> This will get squashed in with the conf patch. I'll also generate the
>> news.html.in entry:
>>
>>           <li>vhost-scsi: Add support scsi_host hostdev passthrough<br/>
>>           Add the capability to pass through a scsi_host HBA and the
>>           associated LUNs to the guest.
>>           </li>
>>
>>
>> ACK -
>>
>> I'll push these in a bit, just seeing what I get on my test system... Of
>> course I'm also curious what would happen if I try to pass through a
>> vHBA ;-)...
> 
> I have unsuccessfully tried it, but not sure how to correctly specify
> the vHBA in domXML.
> 
> First, create a vHBA:
> cat vhba.xml
> <device>
>    <parent_wwpn>2100001b32847342</parent_wwpn>
>    <parent_wwnn>2000001b32847342</parent_wwnn>
>    <capability type='scsi_host'>
>      <capability type='fc_host'>
>       <wwnn>9990100000000001</wwnn>
>       <wwpn>9990000000000001</wwpn>
>       </capability>
>    </capability>
> </device>
> virsh nodedev-create vhba.xml
> 
> (@John: Notice I'm using your "Allow creation of vHBA by
> parent_wwnn/wwpn or fabric_name" series. I'll try to respond with review
> comments on that series tomorrow.)
> 
> Add the vHBA to domain config using a variant of Eric's example:
>   <hostdev mode='subsystem' type='scsi_host'>
>     <source protocol='vhost' wwpn='naa.9990000000000001'/>
>     <address type='ccw' cssid='0xfe' ssid='0x0' devno='0x1000'/>
>   </hostdev>
> 
> Start the VM:
> virsh start test
> error: Failed to start domain test
> error: Path '/sys/kernel/config/target/vhost//naa.5001405df3e54061' is
> not accessible: No such file or directory
> 
> It looks like this patch series only handles scsi_host created with
> targetcli, but I didn't look at all the patches closely. Is it possible
> to use vhost-scsi with NPIV vport (vHBA)? If so, any pointers on how to
> specify the vHBA in <hostdev> element?
> 

I've been buried by other things, but didn't want to ignore completely...

Unfortunately I haven't found a way to use configure w/ vHBA either - I
really was really hoping something could be done. It would have been so
nice to just use XML that would include the scsi_hostN of the vHBA. I
need to find the time to work through what targetcli does - I think it
creates another scsi_hostN which is essentially what is used.  That'd be
similar enough to what vport_create does. Then it would be (hah!) just a
matter of some code ;-) perhaps...

The example Eric has in the cover used multipath which is not something
I generally configure/use. I found some example using google to not use
multipath, but didn't spend too much time with it. I got it to do
something, but then got pinged to work on something else (you know how
that goes!).

John