On Mon, 2 Jan 2023 at 14:37, Borislav Petkov <b...@alien8.de> wrote: > > On Mon, Jan 02, 2023 at 10:32:03AM +0100, Ard Biesheuvel wrote: > > So instead of appending data to the compressed image and assuming that > > it will stay in place, create or extend a memory reservation > > elsewhere, and refer to its absolute address in setup_data. > > From my limited experience with all those boot protocols, I'd say hardcoding > stuff is always a bad idea. But, we already more or less hardcode, or rather > codify through the setup header contract how stuff needs to get accessed. > > And yeah, maybe specifying an absolute address and size for a blob of data and > putting that address and size in the setup header so that all the parties > involved are where what is, is probably better. >
Exactly. In the EFI case, this was problematic because we would need to introduce a new way to pass memory reservations between QEMU and the firmware. But I don't think that issue should affect legacy BIOS boot, and we could just reserve the memory in the E820 table AFAIK.