poor scrolling in qemu-kvm

[Federico Beffa]

Hi,

I'm experimenting with the system in a qemu-kvm virtual machine. I
created an image and successfully booted. However, scrolling of the
display is unusably slow (e.g. displaying dmesg). The same problem is
also visible in Ludovic's presentation

http://audio-video.gnu.org/video/ghm2014/2014-08--courtes--were-building-the-gnu-system--ghm.webm

at about min. 41.

For comparison I run an ubuntu live cd (in text mode) and it performs very well.

Have someone found out the reason for this poor performance in
qemu-kvm and how to fix it?

Thanks,
Fede