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

[Cole Robinson]

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>.

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.

Thanks,
Cole