Comment 12 for bug 710754

No, we go back to 0x100000 (5 zeros ;)) for start and alignment. I have tried in the test environment with both align and start being 0x1000000 (16M) which did *not* work when using pv-grub for the boot process. At that point I wondered whether this is kernel code itself or something going along with pv-grub. So I modified the xen config to load the kernel directly. This works.

Note that the other configuration works as well when using mem=512 for the DomU, just not with mem=615. I did not exhaustively try other memory layouts but at leas 1024 and whatever is used for the m1.medium and c1.small seem to work as well.

In theory the physical (according to the help text) start should not matter when relocatable is set. Though still there is LOAD_PHYSICAL_ADDR calculated from PHYSICAL_START and PHYSICAL_ALIGN and that seems to be used at least in some places even with relocatable turned on (to calculate the delta between compile and load addresses for example).

We probably would have run into this before. Though we carried the defaults which were 0x200000 for amd64 and 0x100000 for i386 until somewhere around 2.6.31. The change to physical start sort of sneaked in when upstream changed the settings this value depends on.