[qemu] Spice your qemu up

Spice is a free and open-source alternative to the VNC protocol. It is actually faster and safer. It enables you to use a remote viewer on your application.

In the host:

apt-get install virt-viewer

This will install remote-viewer, don't use spicec as it is deprecated.

In the guest VM:

apt-get install spice-vdagent

Now let's boot our VM using spice for the display.

qemu-system-x86_64 -drive file=debian_bootstrap2.qcow2,cache=none,if=virtio \ 
--enable-kvm \ 
-net nic,model=virtio,macaddr=52:54:00:12:34:58 \ 
-net vde,sock=/tmp/switch1.ctl -cpu host \ 
-smp 4 -m 2G \ 
-vga qxl -spice port=5900,addr=127.0.0.1,disable-ticketing \ 
-device virtio-serial-pci \ 
-device virtserialport,chardev=spicechannel0,name=com.redhat.spice.0 \ 
-chardev spicevmc,id=spicechannel0,name=vdagent

There is a lot to process here. all the options before the -vga are my usual options, enabling the net via vde (see my post on this here) and enabling virtio for everything.

The -smp 4 option tell kvm to use 4 cores on my computer.

I use -cpu host because I don't want some feature to disappear in the emulation, also It might be faster.

The -vga qxl is the recommanded vga for use with the spice protocol.

The -spice gives the Qemu integrated spice server its configuration. Here we specify the port and the adress of the server. As this is a local setup, we don't need a certified connection, so I disabled the ticketing.

If your VM is on your server, you might want to reconsider this choice as anyone can hijack the connection if you are not careful. Hackers are hardcore people, they are waiting for you in the internet, wearing ski masks and typing in the most awkward position. So encrypt your communications if you don't want to be a victim of these kind of people.






I will describe the use of spice with certificates in another article as you need to set up a CA to get it working.

With these options, you can already use the spice procol to get your virtual machine exported display. In fact you don't need to install the spice-vdagent for that.

But you can get more: copy and paste between the host and the vm and automatic resizing of X.

The -device virtio-serial-pci is the bus where all the virtserialport are plugged, so you need it to declare the use of a virtserialport device.

The -device virtserialport,chardev=spicechannel0,name=com.redhat.spice.0 is the actual port plugged in the virtio serial bus. its name enable the guest agent to connect to it.

The -chardev spicevmc,id=spicechannel0,name=vdagent is the character device to which the spice client will connect to communicate with guest agent using the virtio serial bus.

Now you can connect to your VM using:

remote-viever spice://127.0.0.1:5900

Have fun :)

Links

http://www.linux-kvm.org/page/SPICE
https://wiki.archlinux.org/index.php/QEMU#Spice_support