On 19/08/16 13:57, Jan Beulich wrote: >>>> On 19.08.16 at 14:39, <andrew.coop...@citrix.com> wrote: >> On 19/08/16 08:52, Jan Beulich wrote: >>> Page tables get pre-populated with physical addresses which, due to >>> living inside the Xen image, will never exceed 32 bits in width. That >>> in turn results in the tool generating the relocations to produce >>> 32-bit relocations for them instead of the 64-bit ones needed for >>> relocating virtual addresses. Hence instead of special casing page >>> tables in the processing of 64-bit relocations, let's be more rigid >>> and refuse them (as being indicative of something else having gone >>> wrong in the build process). >>> >>> Signed-off-by: Jan Beulich <jbeul...@suse.com> >> Is it an ABI requirement to use the minimal available relocation? It is >> certainly suboptimal to use a 64bit relocation when a 32bit one would >> do, but I wouldn't bet that it is unconditional avoided by all toolchains. > What ABI? The tool in question is one of our own making. And the > way relocations get generated it's hard to tell those that have to > be 32-bit (in early boot code and trampoline code) from those that > may as well be 64-bit ones (in page tables). > >> It is currently the case that Xen needs to live below 4GB physical, so >> from that point of view a 64bit relocation will not be required in the >> pagetables. > And even if Xen didn't itself have this requirement, the EFI loader > would always put us below 4Gb.
Why is this necessarily true? xen.efi is built as a 64bit PE, not 32bit. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
