Now I am able to mount an NFS fold from Android-x86 running as a KVM guest (VNC as display). The steps I did:
1. Using eeepc-20090820.iso and install it; 2. Boot to debug mode; 3. modprobe sunrpc lockd nfs; 4. netcfg eth0 dhcp; 5. mount -t nfs -o nolock 192.168.xx.xxx:/path/nfs /sdcard, must use the busybox mount here, toolbox mount doesn't work in my case, always report "Invalid argument". I don't know why. 6. then exit the shell so you enter android; 7. Alt+F1 to enter shell again; 8. again: netcfg eth0 dhcp; 9. setprop net.dns1 your-dns-server; 10. route add default gw your-default-gw;
At this point, I am able to browser internet and use OI file manager to access the files in the nfs shared folder.