After installation of a recent version of rawhide as a PV DomU guest, grub.conf was found to have missing spaces between kernel command-line locale defines. grub.conf entry after installation: title Fedora (2.6.31-0.204.rc9.fc12.x86_64) root (hd0,0) kernel /vmlinuz-2.6.31-0.204.rc9.fc12.x86_64 ro root=/dev/mapper/vg_dhcplab136-lv_root rhgb quietLANG=en_US.UTF-8SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us initrd /initrd-generic-2.6.31-0.204.rc9.fc12.x86_64.img Note the missing space in front of LANG and another in front of SYSFONT. This bug is probably not specific to DomU installation, but I haven't tested bare-metal.
This has been fixed a while ago, seems like you are using an old rawhide to test with (the kernel also is somewhat old). *** This bug has been marked as a duplicate of bug 521113 ***