On 2023/4/18 21:50, wangjian (AN) wrote:

On 4/15/23 15:48, wangjian (AN) wrote:

...

Hi Guys,

Currently qemu and spdk already support vhost-user-scsi, but there is no vhost-user-scsi configuration in libvirt.

We hope that libvirt supports the following configurations to facilitate docking with qemu.

<controller type='scsi' index='0' model='vhost-user-scsi'>

<driver queues='4'/>

<source type='unix' path='/var/tmp/scsi'>

<reconnect enabled='yes' timeout='3'/>

</source>

<address type='pci' domain='0x0000' bus='0x02' slot='0x02' function='0x0'/>

</controller>

The usage in qemu like this:

-chardev socket,id=chr-vu-virtio-disk10,path=/var/tmp/scsi,reconnect=3

-device vhost-user-blk-pci,num-queues=4,bus=pci.2,addr=0x0,chardev=chr-vu-virt io-disk10,id=scsi0

Could anyone give some suggestions?

That's very likely because nobody wrote patches for it. I do not think there was a discussion where we decided to deliberately not support it. But I guess, what advantage there is in letting an external helper manage a <controller/> ? I though, vhost-user-* is ideal for individual devices rather than controllers.

Meanwhile, for testing purposes (definitely NOT production), you can use qemu:command line passthrough:

https://libvirt.org/kbase/qemu-passthrough-security.html

Michal

In spdk, a vhost-user-blk controller will only be associated with one disk, and a vhost-user-blk controller will only be associated with one socket file. Therefore, for the vhost-user-blk disk, it is appropriate to use the vhost-user-blk disk associated socket file configuration in libvirt. But in spdk, a vhost-user-scsi controller will be associated with multiple disks, and a vhost-user-scsi controller will only be associated with one socket file. Therefore, we think that for vhost-user-scsi, it is appropriate to use the controller to associate the socket file configuration in libvirt.