[Bug 1596832] Re: e500 -bios/-kernel broken with big images

From: ecsdn <1596832@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Bug 1596832] Re: e500 -bios/-kernel broken with big images
Date: Wed, 18 Dec 2019 21:45:29 -0000	[thread overview]
Message-ID: <157670552938.15344.4033961201302554366.malone@wampee.canonical.com> (raw)
In-Reply-To: 20160628075027.23593.17849.malonedeb@gac.canonical.com

Curious: Is your guest kernel >=3.6 with qemu-ppce500 config ie qemu_ppce500 defined etc? 
In case u-boot loads/maps uImage format kernel differently have you tried uImage vs vmlinux?

And are you able to boot ok with an mpc... machine instead of ppce500 by
specifying a dtb file or dtb compatibility? Do you know if more recent
qemu (2.8 or 3 or 4.2) has same issue for you?

Oh wow I just noticed this is from 2016! It would be nice for such bugs
to have follow-up, closure, or summary of
solution/circumvention/workaround taken by those who posted them :)

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https://bugs.launchpad.net/bugs/1596832

Title:
  e500 -bios/-kernel broken with big images

Status in QEMU:
  New

Bug description:
  This is tested using qemu 2.4.1, but it looks like the code
  qemu/hw/ppc/e500.c has not changed since. This looks like the source
  of the problem:
  http://git.qemu.org/?p=qemu.git;a=commitdiff;h=3812c71ffaa2cf733c3087792b859fef30b7545f

  What works:
  ----------

  Basic invocation qemu-system-ppc -machine ppce500  -monitor stdio
  -bios u-boot.e500 works, I get the uboot prompt and this:

  (qemu) info roms
  addr=0000000000f00000 size=0x044b8c mem=ram name="phdr #0: .../qemu/share/qemu/u-boot.e500"
  addr=0000000000f81000 size=0x006b00 mem=ram name="phdr #1: .../qemu/share/qemu/u-boot.e500"

  Passing u-boot.e500 image as kernel (-bios u-boot.e500 -kernel u-boot.e500) appears to work, $qemu_kernel_addr is filled in, though (as expected) uboot complains about the image format.

  (qemu) info roms
  addr=0000000000f00000 size=0x044b8c mem=ram name="phdr #0: .../qemu/share/qemu/u-boot.e500"
  addr=0000000000f81000 size=0x006b00 mem=ram name="phdr #1: .../qemu/share/qemu/u-boot.e500"
  addr=0000000002000000 size=0x054e8c mem=ram name=".../qemu/share/qemu/u-boot.e500

  What doesn't work:
  -----------------

  However, once I try to load a big image (>=32 MiB), uboot doesn't even
  show anything:

  qemu-system-ppc -machine ppce500  -monitor stdio -bios u-boot.e500
  -kernel boot/vmlinux -m 1024

  (qemu) info roms
  addr=0000000000f00000 size=0x044b8c mem=ram name="phdr #0: .../qemu/share/qemu/u-boot.e500"
  addr=0000000000f81000 size=0x006b00 mem=ram name="phdr #1: .../qemu/share/qemu/u-boot.e500"
  addr=0000000002000000 size=0x27aeedc mem=ram name="boot/vmlinux"

  ...
  (gdb) bt
  #0  0x00f2efcc in ?? ()
  #1  0x00f31554 in ?? ()
  #2  0x00f03f4c in ?? ()
  #3  0x00f04458 in ?? ()
  #4  0x00f028dc in ?? ()
  #5  0x00f01080 in ?? ()

  The thing is, this used to work +- before the commit, where I'd just
  pass the image as -kernel option, and it booted.

  If I do that now (w/o the -bios option, using the exact same image), the kernel gets loaded twice, only at different addresses (the cause is obvious from the commit), causing overlap error:

  qemu-system-ppc -machine ppce500  -monitor stdio  -kernel boot/vmlinux -m 1024
  QEMU 2.4.1 monitor - type 'help' for more information
  (qemu) rom: requested regions overlap (rom boot/vmlinux. free=0x00000000027492fc, addr=0x0000000002000000)

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