Dear all:
I tried to run qemu-kvm from my gnome-terminal after using a non-root account to locally login my XWindow Desktop.
This is what I did in the gnome-terminal:

sudo /usr/bin/qemu-kvm -m 1024 -name f15 -drive file=/home/joe/Images/FreeDOS-1.1-memstick-2-2048M.img,if=virtio -fsdev local,security_model=passthrough,id=fsdev0,path=/tmp -device virtio-9p-pci,id=fs0,fsdev=fsdev0,mount_tag=hostshare

However, after I entered the root password, it gave me the following message --

Could not initialize SDL(No available video device) - exiting

Then I realized one of the root causes was because I cannot sudo any gui applications under such conditions. For examples:

[B}sudo xterm[/B]
xterm Xt error: Can't open display: %s
xterm: DISPLAY is not set

The standard soultion is to use gnomesu, xdg-su, and so on.

But in the qemu-kvm case, apparently it does not work out by using such solutions.

Can any one give me any help?

Thank you anyway.