Re: [Qemu-devel] [PATCH 0/3] hw/core: minor fixups

[Philippe Mathieu-Daudé]

Hi Eduardo,

On 06/23/2017 04:45 PM, Eduardo Habkost wrote:
> Do you have a simple way to trigger the error paths addressed by patches 1/3
> and 2/3?

For 1/3 "elf-loader: warn about invalid endianess":

$ wget -q 
https://people.debian.org/~aurel32/qemu/mips/vmlinux-3.2.0-4-4kc-malta

$ file vmlinux-3.2.0-4-4kc-malta
vmlinux-3.2.0-4-4kc-malta: ELF 32-bit MSB executable, MIPS, MIPS32 
version 1 (SYSV), statically linked, 
BuildID[sha1]=66b8748075269e8aedb91d363050f74af8a0ebdd, not stripped

$ qemu-system-mipsel -version
QEMU emulator version 2.8.1(Debian 1:2.8+dfsg-6)
Copyright (c) 2003-2016 Fabrice Bellard and the QEMU Project developers

$ qemu-system-mipsel -kernel vmlinux-3.2.0-4-4kc-malta
qemu: could not load kernel 'vmlinux-3.2.0-4-4kc-malta'

Once applied:

$ mipsel-softmmu/qemu-system-mipsel -kernel vmlinux-3.2.0-4-4kc-malta
vmlinux-3.2.0-4-4kc-malta: wrong endianess
qemu: could not load kernel 'vmlinux-3.2.0-4-4kc-malta'

It could be more verbose/nicer.

I'm doing some dual endianness tests and sometimes it happened I only 
notice I'm stupid enough to load the wrong elf once stepping in gdb...


For 2/3 "fix missing return value in load_image_targphys_as()" I 
extracted it from a WiP branch "unify-arm-mips-loaders" think that if I 
never finish it, at least this one can still be useful for others.
No commits in this branch since 4months so I don't really remember how 
it happens, but looking at rom_add_file() I see:

        fprintf(stderr, "Could not open option rom '%s': %s\n",
                rom->path, strerror(errno));
        goto err;
...
        fprintf(stderr, "rom: file %-20s: get size error: %s\n",
                rom->name, strerror(errno));
        goto err;
...
        fprintf(stderr, "rom: file %-20s: read error: rc=%d (expected 
%zd)\n",
                rom->name, rc, rom->datasize);
        goto err;

So my guess is again I missed something in the command line I used (used 
unfinished bash auto-complete which lead to a directory? use zipped 
rom?) and QEMU was still booting without using the specified rom.

I do remember single stepping there at least 2 times before realize 
again how stupid I was :)

Regards,

Phil.