The following patch implements vmmouse emulation for i386 and x86_64.  
Xorg has included an open source vmmouse driver since 7.1 and it is 
available in many distros.

vmmouse supports absolute and relative modes.  It's based on a queue 
that's read through PIO but it still uses the PS2 port for notification.

I've tested i386-softmmu and save/restore.  Everything seems to work nicely.

To use it, first install the vmmouse driver.  For ubuntu, starting with 
Edgy, it's xserver-xorg-input-vmmouse in the universe.  Then, in your 
Input section, change the "mouse" driver to "vmmouse".

Regards,

Anthony Liguori