Re: [Qemu-devel] [PATCH] Fix leul_to_cpu on big endian hosts

[Aurelien Jarno <aurelien@aurel32.net>]

On Mon, May 31, 2010 at 08:44:55PM +0200, Alexander Graf wrote:
> Aurelien Jarno wrote:
> > On Tue, May 11, 2010 at 05:38:17PM +0200, Alexander Graf wrote:
> >   
> >> Commit 213acd2e introduced leul_to_cpu with a special code path for big endian
> >> hosts. Unfortunately that code used preprocessor magic that didn't work.
> >>
> >> This patch replaces the explicit ##s by glue() which is proven to work reliably,
> >> enabling me to compile qemu on ppc again.
> >>
> >> Signed-off-by: Alexander Graf <agraf@suse.de>
> >> ---
> >>  bswap.h |    2 +-
> >>  1 files changed, 1 insertions(+), 1 deletions(-)
> >>
> >> diff --git a/bswap.h b/bswap.h
> >> index 956f3fa..20caae6 100644
> >> --- a/bswap.h
> >> +++ b/bswap.h
> >> @@ -205,7 +205,7 @@ static inline void cpu_to_be32wu(uint32_t *p, uint32_t v)
> >>  
> >>  #ifdef HOST_WORDS_BIGENDIAN
> >>  #define cpu_to_32wu cpu_to_be32wu
> >> -#define leul_to_cpu(v) le ## HOST_LONG_BITS ## _to_cpu(v)
> >> +#define leul_to_cpu(v) glue(glue(le,HOST_LONG_BITS),_to_cpu)(v)
> >>  #else
> >>  #define cpu_to_32wu cpu_to_le32wu
> >>  #define leul_to_cpu(v) (v)
> >>     
> >
> > While the patch looks correct, I am not able to reproduce the issue. Do
> > you have more details about it?
> >   
> 
> When building on a KVM capable PPC host (or S390 for that matter), I get
> the following:
> 
> cc1: warnings being treated as errors
> /home/agraf/release/qemu/kvm-all.c: In function
> ‘kvm_get_dirty_pages_log_range’:
> /home/agraf/release/qemu/kvm-all.c:305: error: implicit declaration of
> function ‘leHOST_LONG_BITS_to_cpu’
> make[1]: *** [kvm-all.o] Error 1
> make[1]: *** Waiting for unfinished jobs....
> make: *** [subdir-ppc64-softmmu] Error 2
> 

Ok, that make sense now. I have tried to build on a big endian host, but
KVM was not enabled. Strangely this function is also used at other
places, so I was expecting the build to fail.

Applied now.

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net