QEMU-KVM

Shared Directory

In Virt-Manager under VM settings “Add Hardware → File system”

Source: Directory on Host that will be shared
Target: Any name (without space) will be used in fstab

On the Guest create a directory to be used as mount point

Then add the following in /etc/fstab:

<target-name> <path-on-guest> 9p trans=virtio,rw 0 0

sudo mount -a

If the above command produces an error fix it before continuing.

After that goto /etc/initramfs-tools/modules and add the following:

9p
9pnet
9pnet_virtio

Then,

sudo update-initramfs -u

This will load the drivers required for the shared directory on system startup.

Shared Clipboard

Install the following packages using the systems package manager:

sudo apt install qemu-guest-agent spice-vdagent

After reboot clipboard sharing and automatic VM resizing should work

VM Creation Permission Issue

Go to /etc/libvirt/qemu.conf and modify the following line:

user = "<username>"
group = "libvirt"

Windows VirtIO Drivers

To use VirtIO based storage on Windows, the virtio driver has to be installed.

VirtIO Drivers - Download

The driver is provided as an ISO file that has to be mounted on a CD ROM when installing the operating system (Add Hardware → Storage → CD-ROM device)

Network Disabled

The virsh command can be used to enable a network if its disabled

sudo virsh net-list --all
sudo virsh net-start <network-name>
 
sudo virsh net-autostart <network-name>

VM Performance Settings

For CPU enable host-passthrough
For Disk set Cache Mode to None and Discard Mode to Unswap
Remove the Tablet Hardware
Some VMs require Video to be set to QXL (Windows, Kali Linux, etc.)