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Using VirtIO-FS for Host-Guest File Sharing

VirtIO-FS is a high-performance shared filesystem that lets you share a directory from your host machine directly with a guest VM.

Host Prerequisites

  1. Shared Memory: VirtIO-FS requires shared memory to be enabled for the VM. You can enable this in the "Mem" tab.
  2. Permissions: The user running QEMU/libvirt on the host must have the necessary permissions to read (and write, if needed) the source directory you want to share.

Adding a VirtIO-FS Mount

  • Source Path: The absolute path to the directory on your host machine that you want to share.
  • Target Path: This is a "mount tag" or a label that the guest VM will use to identify the shared directory. It is not a path inside the guest. For example, you could use shared-data.

Mounting in a Linux Guest

Most modern Linux distributions include the necessary VirtIO-FS drivers.

1. Create a Mount Point: This is the directory inside your VM where the shared files will appear.

sudo mkdir /mnt/my_host_share

2. Mount the Share: Use the mount command with the filesystem type virtiofs and the Target Path (mount tag) you defined.

sudo mount -t virtiofs 'your-target-path' /mnt/my_host_share
(Replace 'your-target-path' with the actual tag you set)

3. Automount on Boot (Optional): To make the share available automatically every time the VM boots, add an entry to /etc/fstab:

your-target-path /mnt/my_host_share virtiofs defaults,nofail 0 0

The nofail option is recommended to prevent boot issues if the share is not available.

Mounting in a Windows Guest

1. Install Drivers: You must install the VirtIO-FS drivers in the Windows guest. These are included in the "VirtIO-Win Guest Tools" package or the "Virtual Machine Driver Pack (VMDP)". - Option A (SUSE VMDP): Use the Virtual Machine Driver Pack (VMDP) for a comprehensive set of optimized drivers. - Option B (Fedora): Download the latest stable virtio-win.iso from the Fedora VirtIO-Win project. - Attach the chosen ISO to your VM as a CD-ROM. - Open the CD-ROM in Windows and run the installer, ensuring the "VirtIO-FS" feature is selected.

2. Access the Share: After installation and a reboot, the VirtIO-FS service will start. The shared folder will automatically appear as a network drive in This PC (or My Computer). The drive will be named after the Target Path (mount tag) you set.