Xen devel - Jul 2013 - Linux v3.10 and a new config option that is not enabled by default ... CONFIG_HYPERVISOR_GUEST=y

If you compiled your kernel and booted under Xen and got:


(XEN) *** LOADING DOMAIN 0 ***
(XEN) elf_parse_binary: phdr: paddr=0x1000000 memsz=0x9db000
(XEN) elf_parse_binary: phdr: paddr=0x1a00000 memsz=0xa30f0
(XEN) elf_parse_binary: phdr: paddr=0x1aa4000 memsz=0x13c00
(XEN) elf_parse_binary: phdr: paddr=0x1ab8000 memsz=0x206000
(XEN) elf_parse_binary: memory: 0x1000000 -> 0x1cbe000
(XEN) elf_xen_note_check: ERROR: Will only load images built for the generic
loader or Linux images
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) Could not set up DOM0 guest OS
(XEN) ****************************************
(XEN) 
(XEN) Reboot in five seconds...
(XEN) Resetting with ACPI MEMORY or I/O RESET_REG.

That is b/c v3.10 has a new config option (CONFIG_HYPERVISOR_GUEST)
which has KVM, Xen, VMWare, etc under it.

So, add this in your .config: CONFIG_HYPERVISOR_GUEST=y
and everything will be back to normal.