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

Michal Prívozník mprivozn at
Fri May 14 13:15:45 UTC 2021

On 5/14/21 8:33 AM, 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"

Smells like problem described here:

But that's pretty fresh commit (part of qemu 6.0.0 release). And also
the commit it references is not that old (qemu 5.1.0 release). What
version of qemu are you running?


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