To allow the megaraid_sas driver to load correctly you must add parameters to Oracle VM:
When installing Oracle VM 2.x, add the following kernel parameters:
mboot.c32 xen.gz extra_guest_irqs=64,2048 nr_irqs=2048 --- vmlinuz --- initrd.img
If booting from the installation media, press F2 when the initial boot screen is displayed and add the above parameters to the boot command.
If using a kickstart installation, add the above parameters to the PXE configuration file.
For all Oracle VM installations, edit the /boot/grub/grub.conf file in your Oracle VM Server and add: extra_guest_irqs=64,2048 nr_irqs=2048