KDM In KDE SC 4.7 To Play With GRUB2
Phoronix: KDM In KDE SC 4.7 To Play With GRUB2
The KDM code for KDE SC 4.7 has just gained one small but noteworthy feature: GRUB2 support. While the KDE Display Manager gaining support for the GRUB2 boot-loader may seem nonchalant, it's actually quite useful. Now from the KDE Display Manager, users are able to select another GRUB boot entry without affecting the default choice or having to wait for the boot-loader to appear when rebooting...
KDM + Grub + SELinux interactions
Out of the box, SELinux doesn't allow KDM to make these Grub modifications
As mentioned in that report, there is a SELinux boolean you can use. Even with it set though it still won't work. It's easiest to just disable SELinux if you want KDM to control Grub.