/etc/initramfs-tools/modules
# List of modules that you want to include in your initramfs.
# They will be loaded at boot time in the order below.
#
# Syntax: module_name [args ...]
#
# You must run update-initramfs(8) to effect this change.
#
# Examples:
#
# raid1
# sd_mod
9p
9pnet
9pnet_virtio
Then:
update-initramfs -u
In /etc/pve/qemu-server/xxx.conf
args: -fsdev local,security_model=passthrough,id=fsdev0,path=/tank/media -device virtio-9p-pci,id=fs0,fsdev=fsdev0,addr=0x4,mount_tag=media_share