Hello On Thu, Aug 17, 2017 at 1:54 PM, Anatol Pomozov <anatol.pomo...@gmail.com> wrote: > Hi > > On Tue, Aug 8, 2017 at 8:04 AM, Kevin Wolf <kw...@redhat.com> wrote: >> Am 04.08.2017 um 06:53 hat Anatol Pomozov geschrieben: >>> Hi Kevin >>> >>> Thanks for the information. >>> >>> So I sounds like we do want multiboot to load all sections regardless >>> of its segments info. To achieve it we need to read sections headers >>> and load all section that were not loaded yet. >>> >>> I have a working implementation here >>> https://github.com/anatol/qemu/commit/26773cf4f1f30b2d0d3fd89cce024f8e9c5603c5 >>> Tested it with my multiboot OS image. The target iterates over all >>> sections and prints their names/address. The output result is the same >>> for QEMU and for VmWare+GRUB. >>> >>> Let me know if this idea looks good so I can send this patch to qemu >>> maillist. >> >> I'm not sure if I'll find the time to review this in detail, but I'll >> just give it a quick look. >> >> You seem to attempt to add support for 64 bit ELF binaries. The >> Multiboot standard doesn't explicitly say that this is forbidden, but >> everything in it expects 32 bit binaries and I don't think GRUB (as the >> reference implementation for Multiboot) accepts 64 bit ELFs either. The >> boot state is 32 bit protected mode in any case. So unless I'm mistaken >> on GRUB's behaviour, I'd rather not support 64 bit ELFs. > > Grub actually does support ELF64 loading with multiboot. Here is the > GRUB code that implements it > https://github.com/coreos/grub/blob/master/grub-core/loader/multiboot.c#L210 > > It would be great if QEMU behaved similar way. > > Actually I've been using qemu with ELF64 multiboot for a while and it > works great. > >> >> You shouldn't look at ELF headers at all if MULTIBOOT_AOUT_KLUDGE is >> given. In this case, the kernel image is to be treated as a flat binary >> and section headers can't be expected. I think your code breaks non-ELF >> kernels.
I have these changes ready now http://lists.nongnu.org/archive/html/qemu-devel/2017-08/msg03265.html It added ELF parser functionality as discussed above. Are there any open questions? What is the best way to proceed forward with these patches? I also have interest in adding Multiboot2 support to qemu. But before going with it I would like to finish working on my current patchset.
