How to hot plugin a new vhost-user-blk-pci device to running VM?

[Peter Krempa]

On Fri, May 14, 2021 at 14:33:37 +0800, Liang Chaojun wrote:
> 
> 
> 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"

As noted, this is not an interface we'd provide support for. Please
upgrade both libvirt and qemu and try the supported interface if you
want us to deal with any problems you might have.