qemu-img convert debian10.img -O raw debian10.raw
VBoxManage convertfromraw debian10.raw --format vdi debian10.vdi

Check nested virtualization inside QEMU :

For kvm_intel module, check /sys/module/kvm_intel/parameters/nested is “Y”… Else

# If you have an Intel CPU, use this:
$ cat > /etc/modprobe.d/kvm_intel.conf
options kvm-intel nested=Y

Enable Intel VMX cpu flag in bios, then in /etc/default/grub and add “intel_iommu=on” to GRUB_CMDLINE_LINUX line. Then, sudo update-grub

Check IOMMU is OK with command: virt-host-validate qemi

• https://www.linux-kvm.org/page/Nested_Guests
• https://www.linux-kvm.org/page/How_to_assign_devices_with_VT-d_in_KVM
• https://scottlinux.com/2017/05/10/how-to-enable-iommu-support-in-fedora-linux/

Quick Test:

$ qemu-system-x86_64 -vnc :0
$ vncviewer localhost

If you get the error message “Could not read keymap file: 'en-us'”, you will need to install an extra package:

$ sudo apt-get install qemu-system-data

More: https://wiki.archlinux.org/index.php/QEMU#VNC

Spice is similar to VNC… Need special graphic card “qxl”

$ qemu-system-x86_64 -vga qxl -spice port=5900,addr=127.0.0.1,disable-ticketing

Se connecter avec un viewer à la VM avec:

$ sudo apt-get install virt-viewer
$ remote-viewer spice://127.0.0.1:5900

In order to add copy & paste support:

$ SPICEOPT="-vga qxl -spice port=5900,addr=127.0.0.1,disable-ticketing"
$ SPICEMORE="-device virtio-serial -chardev spicevmc,id=vdagent,name=vdagent -device virtserialport,chardev=vdagent,name=com.redhat.spice.0"
$ qemu-system-x86_64 -enable-kvm -hda kali.img  -name syl -m 2G $SPICEOPT $SPICEMORE

Installer spice-vdagent sur le guest (linux).

$ sudo apt-get install spice-vdagent

Pour windows, il faut installer : https://www.spice-space.org/download/windows/spice-guest-tools/spice-guest-tools-latest.exe

Demarrer space-vdagentd au boot et spicevdagent apres le login X.

More: https://www.linux-kvm.org/page/SPICE