libvirt users - May 2021 - How to hot plugin a new vhost-user-blk-pci device to running VM?

On Thu, May 13, 2021 at 23:11:36 +0800, Liang Chaojun
wrote:
> 
> 
> Thanks Peter for your quickly response. Is there any workaround to do
that?As you know we must take care the risk of using latest version in product
environment.
Manual approach is to use 'virsh qemu-monitor-command' or the equivalent
to attach the appropriate backends and frontends manually.

Obviously that is very far from anything I'd recommend to use in any
production environment.

Thanks?I have tried qemu monitor as below. I used chardev_add to add a chardev
and used device_add it to running vm. But i often hit a issue and cause the vm
crash. qemu-system-x86_64: ../hw/virtio/vhost.c:1566: vhost_dev_get_config:
Assertion `hdev->vhost_ops' failed.

virsh qemu-monitor-command spdk1 --hmp --cmd "chardev-add
socket,id=spdk_vhost_blk0,path=/var/tmp/vhost.0,reconnect=1"  virsh
qemu-monitor-command spdk1 --hmp --cmd "device_add
vhost-user-blk-pci,chardev=spdk_vhost_blk0,num-queues=4"
> ? 2021?5?14??00:47?Peter Krempa <pkrempa at redhat.com> ???
> 
> ?On Thu, May 13, 2021 at 23:11:36 +0800, Liang Chaojun wrote:
>> 
>> 
>> Thanks Peter for your quickly response. Is there any workaround to do
that?As you know we must take care the risk of using latest version in product
environment.
> 
> Manual approach is to use 'virsh qemu-monitor-command' or the
equivalent
> to attach the appropriate backends and frontends manually.
> 
> Obviously that is very far from anything I'd recommend to use in any
> production environment.
>

Thanks?I have tried qemu monitor as below. I used chardev_add to add a chardev
and used device_add it to running vm. But i often hit a issue and cause the vm
crash. qemu-system-x86_64: ../hw/virtio/vhost.c:1566: vhost_dev_get_config:
Assertion `hdev->vhost_ops' failed.

virsh qemu-monitor-command spdk1 --hmp --cmd "chardev-add
socket,id=spdk_vhost_blk0,path=/var/tmp/vhost.0,reconnect=1"  virsh
qemu-monitor-command spdk1 --hmp --cmd "device_add
vhost-user-blk-pci,chardev=spdk_vhost_blk0,num-queues=4"
> ? 2021?5?14??00:47?Peter Krempa <pkrempa at redhat.com> ???
> 
> ?On Thu, May 13, 2021 at 23:11:36 +0800, Liang Chaojun wrote:
>> 
>> 
>> Thanks Peter for your quickly response. Is there any workaround to do
that?As you know we must take care the risk of using latest version in product
environment.
> 
> Manual approach is to use 'virsh qemu-monitor-command' or the
equivalent
> to attach the appropriate backends and frontends manually.
> 
> Obviously that is very far from anything I'd recommend to use in any
> production environment.
>