[libvirt] [PATCH 1/2] Add VSCSI bus type and VSCSI controller type for pseries guest.

[Li Zhang]

On 05/30/2012 07:25 AM, Cole Robinson wrote:
> On 05/03/2012 10:05 PM, Li Zhang wrote:
>> Now, there is only SCSI bus and controller type in libvirt.
>> And when configuring VSCSI controller, it needs to configure
>> the spapr-vio bus address type externally. It's a little
>> inconvenient to configure the controller type.
>>
>> This patch is to add VSCSI bus type and VSCSI controller type.
>> And handle with the problems when VSCSI and SCSI devices
>> working together, by assign the even number to index of
>> VSCSI controller and odd number to index of SCSI controller.
>>
>> And when the VSCSI controller is always assigned as SPAPRVIO
>> bus address type and SCSI controller will be always assigned
>> as PCI bus address, which is implemented according to the
>> controllers' type.
>>
>> So when one disk is based on VSCSI controller, then assign
>> the bus as 'vscsi', and one right VSCSI controller will be
>> selected.
>>
>> If one disk is based on VSCSI controller, the XML file is
>> as the following:
>>
>> <disk type='file' device='disk'>
>>     <driver name='qemu' type='raw'/>
>>     <source file='/path/file'/>
>>     <target dev='sda' bus='vscsi'/>
>> </disk>
>>
>> VSCSI controllers' configuration in XML file will be like
>> this:
>>
>> <controller type='vscsi' index='0'>
>> </controller>
>>
>> If one disk is based on 'vscsi', the 'vscsi' bus should be assigned
>> externally. Otherwise, it will be set as 'scsi' bus according
>> to the 'sd' target prefix of the disk.
>>
>
> First off, sorry for taking so long to respond.
>
> This isn't exactly what I had in mind when I recommended a libvirt patch.
> Change libvirt to add:
>
>      <controller type='scsi' index='0'>
>          <address type='spapr-vio'/>
>      </controller>
>
> when the guest XML has
>
> <disk type='file' device='disk'>
>      <driver name='qemu' type='raw'/>
>      <source file='/path/file'/>
>      <target dev='sda' bus='scsi'/>
>      <address type='spapr-vio'/>
> </disk>
>
> and the guest XML doesn't already have spapr-vio<controller>.

Thanks a lot for your suggestion. :)

I see the libvirt will always set the address type of the disk as
"drive". There is one drive address structure in libvirt, which
records the controller, bus and unit.

the address can be specified in the target.

  <disk type='file' device='disk'>
       <driver name='qemu' type='raw'/>
       <source file='/path/file'/>
       <target dev='sda' bus='scsi' address='spapr-vio'/>
       <address type='drive' controller='0' bus='0' unit='0' />
  </disk>

>
> Then virt-manager etc. only needs to know that for pseries guests, the
> default disk should use bus='scsi' and<address type='spapr-vio'/>, and
> libvirt will auto add the correct<controller>  for us, like it does for ide,
> sata, etc. already.
>
> The patch has obviously weird logic with the even/odd approach, so I think
> this approach is better.

Yes, I see. Thanks. :)

>
> Thanks,
> Cole
>


-- 
Best Regards
Li

IBM LTC, China System&Technology Lab, Beijing