What were you trying to do that didn't work?

Hot-unplug and hot-plug vhost-user-fs-ccw and mount it to see if the I/O is as expected

Please provide the package NVR for which bug is seen:

kernel version: kernel-5.14.0-447.el9.s390x

qemu version: qemu-kvm-9.0.0-2.el9.s390x

libvirt version: libvirt-10.0.0-7.el9.s390x

How reproducible:

100%

Steps to reproduce

1. boot up guest without virtiofs device
2. Running virtiofs daemon command
   1. /usr/libexec/virtiofsd --socket-path=/tmp/vhostqemu -o source=/home/virtiofs_test -o cache=auto
3. hotplug the vhost-user-fs-ccw device
   1. {"execute": "chardev-add", "arguments": {"id": "char_virtiofs_fs", "backend": {"type": "socket", "data": {"addr": {"type": "unix", "data": {"path": "/tmp/vhostqemu"}}, "server": false}}}, "id": "hNeu2XwD"}
   2. {"execute": "device_add", "arguments": \{"id": "vufs_virtiofs_fs", "chardev": "char_virtiofs_fs", "tag": "myfs", "queue-size": 1024, "driver": "vhost-user-fs-ccw", "bus": "virtual-css"}

      , "id": "g81TVOH9"}

4. mount the divice and do simple I/O test
   1. mount -t virtiofs myfs /mnt/myfs
   2. dd if=/dev/urandom of=/mnt/myfs/test_file bs=1M count=200 oflag=direct
   3. md5sum /mnt/myfs/test_file
5. unplug the vhost-user-fs-ccw device
   1. fuser -km /mnt/myfs
   2. umount /mnt/myfs
   3. rm -rf /mnt/myfs
   4. {"execute": "device_del", "arguments": \{"id": "vufs_virtiofs_fs"}

      , "id": "fQhD033H"}

   5. {"execute": "chardev-remove", "arguments": \{"id": "char_virtiofs_fs"}

      , "id": "3TqUdSKY"}

6. Running virtiofs daemon command again
   1. /usr/libexec/virtiofsd --socket-path=/tmp/vhostqemu -o source=/home/virtiofs_test -o cache=auto
7. hot plug the vhost-user-fs-ccw device again
   1. {"execute": "chardev-add", "arguments": {"id": "char_virtiofs_fs", "backend": {"type": "socket", "data": {"addr": {"type": "unix", "data": {"path": "/tmp/vhostqemu"}}, "server": false}}}, "id": "hNeu2XwD"}
   2. {"execute": "device_add", "arguments": \{"id": "vufs_virtiofs_fs", "chardev": "char_virtiofs_fs", "tag": "myfs", "queue-size": 1024, "driver": "vhost-user-fs-ccw", "bus": "virtual-css"}

      , "id": "1TtPmAcA"}

Expected results

virtio-fs device could hostplug successfully

Actual results

QEMU 9.0.0 monitor - type 'help' for more information
(qemu) qemu-kvm: virtio_bus_set_host_notifier: unable to assign ioeventfd: -17
qemu-kvm: vhost VQ 0 notifier binding failed: 17
qemu-kvm: Error enabling host notifiers: 17
qemu-kvm: virtio_bus_set_host_notifier: unable to assign ioeventfd: -17
qemu-kvm: virtio_bus_start_ioeventfd: failed. Fallback to userspace (slower).

and the device is not able to mount

Additional info

[root@localhost ~]# [  391.494776] SELinux: (dev virtiofs, type virtiofs) getxattr errno 4