I have
            download xen unstable tree which include your efi patch,and
            try to build xen.efi ,but there only have xen.gz ,don't have
            xen.efi .I find the file xen\arch\x86\efi\disable have
            report some error : ld don't  support -m i386pep.  my gcc
            version is 4.6.1.
            if modify the i386pep to elf_x86_64 ,the build can continue
            ,and report other error --subsystem=10 and
            --image-base=0xffff82c480000000 unrecognized.
            do you have any suggestion about that?  thank you very much!
            
            the detail is follow.
            
ld: unrecognized
              option '--image-base=0xffff82c480000000'
            
            
            
            In the xen/arch/x86/efi/disabled
            ld: unrecognized emulation mode: i386pep
            Supported emulations: elf_x86_64 elf32_x86_64 elf_i386
            i386linux elf_l1om