Re: [Qemu-devel] [PATCH v2 for-1.7] s390x: fix flat file load on 32 bit systems

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Thu, 21 Nov 2013 14:52:02 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> pc-bios/s390-zipl.rom is a flat image so it's expected that
> loading it as elf will fail.
> It should fall back on loading a flat file, but doesn't
> on 32 bit systems, instead it fails printing:
>     qemu: hardware error: could not load bootloader 's390-zipl.rom'
> 
> The result is boot failure.
> 
> The reason is that a 64 bit unsigned interger which is set
> to -1 on error is compared to -1UL which on a 32 bit system
> with gcc is a 32 bit unsigned interger.
> Since both are unsigned, no sign extension takes place and
> comparison evaluates to non-equal.
> 
> There's no reason to do clever tricks: all functions
> we call actually return int so just use int.
> In fact ram_addr_t dos not make any sense -
> it's meaning is "memory handle for migration".
> 
> And then we can use == -1 everywhere, consistently.
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> 
> Changes from v1:
>     better fix: use int everywhere
>     fix all places with same bug (e.g. -kernel was broken too)
> 
>  hw/s390x/ipl.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>