Virtio-fs, shorts for Virtio shared FileSystem, allows for a directory located on the host to be shared with a guest.
It is designed to be fast and optimized for local usage, when the host and the guest are located on the same physical machine. It is therefore a perfect fit for Phyllome OS.
Just as with other virtio devices, virtio-fs requires specialized drivers to be written for the host and the guest operating system.
For KVM/QEMU, as of January 2023, virtio-fs is only available for virtual machines managed by the system libvirt instance (
qemu:///system)
As of January 2023,
virtio-fsdoes not support read-only mode, meaning a guest will be able to write to the host's folder.
<domain type="kvm">
[...]
<memoryBacking>
<source type="memfb"/>
<access mode="shared/>"
</memoryBacking>
[...]
</domain>
/opt/share/ will be shared with the guest:<domain type="kvm">
[...]
<devices>
[...]
<filesystem type="mount" accessmode="passthrough">
<driver type="virtiofs"/>
<source dir="/opt/share"> # The host directory to be shared with the guest
<target dir="share"> # The target dir value refers to the mount tag used inside the guest, not the target dir inside the guest
</filesystem>
[...]
</devices>
[...]
</domain>
/opt/share host directory to the guest, using also the /mnt point:# mount -t virtiofs share /mnt/
/etc/fstab:share /mnt/ virtiofs rw,noatime,_netdev 0 2
systemd daemon`# umount /mnt/ && systemctl daemon-reload
fstab:# mount -all