[ipxe-devel] 0xc000000d

[Christian Nilsson]

On Tue, Apr 21, 2015 at 11:31 PM, Christian Nilsson <nikize at gmail.com> wrote:
> Are you using wimboot and get the 0xc000000d error from windows bootmgr?
> Could you share relevant parts of your boot script so that we see
> which files are loaded and how?
>
> It could also be interesting to know how much memory it is in the
> affected machines and their brand.
>
> I have seen one other similar report, and that issue is currently
> being investigated.
> In that case there is an issue when it has 4Gb of memory but removing
> one module it works fine. (absolutely not a fix, just a way to
> identify if the issue are the same)
>
> /Christian

Have been looking in to if not identical, atleast similar issue
together with Casper on IRC. (he sent a different mail that I'm unable
to find at the moment)
The exact issue:
On Real HW This issue is triggerd on all tested EFI capable machines
but only in legacy mode that has 4Gb or more.
The affected wim image is Windows 7 based x86
No issues when running in EFI mode or any other version of winpe as
far as we have found.

If ipxes memblock.c is patched to use max 0x80200000 (and the memmap
allow its use), the wim is loaded at 0x72d5a079 and end at 0x801ff781
and the 0xc000000d bootmgr error is seen "An unexpected error has
occurred." (on other occations 0xc0000017 is seen instead)

To reproduce and trigger this in qemu, force lowmem = 0x80400000 in
pc_q35_init (hw/i386/pc_q35.c)
command: qemu-system-x86_64 -machine type=q35,accel=kvm -m 4096

Running qemu and dumping the memory for the loaded files - they all
match both when wimboot is paused and when bootmgr gives the
0xc00000xx error. So atleast no hidden memory corruption. as far as I
understand.

Next step i guess is to debug bootmgr and possible the kernel, which I
have not so far had time for.

Script used as simple as possible:
#!ipxe
kernel wimboot pause
initrd BCD            BCD
initrd boot.sdi       boot.sdi
initrd boot.wim       boot.wim
imgstat
boot

using different bootmgr.exe does not help either, and BCD does not
have any impact (other than minor change of memorylocations due to
file sizes)
Test script and orginal known "issue wim" can be provided in private
on request, (will be sent separate to Michael if you could take a
look)

/Christian