On 14.03.2024 15:13, Jason Andryuk wrote: > On 2024-03-14 09:21, Jan Beulich wrote: >> On 13.03.2024 20:30, Jason Andryuk wrote: >>> --- a/xen/include/public/elfnote.h >>> +++ b/xen/include/public/elfnote.h >>> @@ -194,6 +194,17 @@ >>> */ >>> #define XEN_ELFNOTE_PHYS32_ENTRY 18 >>> >>> +/* >>> + * Physical loading constraints for PVH kernels >>> + * >>> + * Used to place constraints on the guest physical loading addresses and >>> + * alignment for a PVH kernel. This note's value is 3 64bit values in >>> + * the following order: minimum, maximum and alignment. >> >> Along the lines of what I said on another sub-thread, I think at least >> alignment wants to be optional here. Perhaps, with max going first, min >> could also be optional. > > Interesting idea. > >> As indicated in different context by Roger, the values being uniformly >> 64-bit ones also is questionable. >> >>> + * The presence of this note indicates the kernel is relocatable. >> >> I think it wants making explicit here that the act of relocating is still >> left to the kernel. > > Ok. > > How is this for a new description? > > """ > Physical loading constraints for PVH kernels > > Used to place constraints on the guest physical loading addresses and > alignment for a PVH kernel. > > The presence of this note indicates the kernel supports relocating itself. > > The note may include up to three 32bit values.
I'm as unsure about always 32-bit as I am on it being uniformly 64-bit. One question here is whether this note is intended to be x86-specific. > - a maximum address for the entire image to be loaded below (default > 0xfffffff) One f too few? > - a minimum address for the start of the image (default 0) > - a required start alignment (default 1) > """ > > I think if we can agree on the ELF note, the rest will fall into place. Presumably, yes. Jan
