Re: [Qemu-devel] [PULL 00/23] TCG and misc patches for 2.7 hard freeze from 2016-07-18

[Paolo Bonzini]

On 18/07/2016 13:51, Peter Maydell wrote:
> On 18 July 2016 at 10:27, Paolo Bonzini <address@hidden> wrote:
>> The following changes since commit 6b92bbfe812746fe7841a24c24e6460f5359ce72:
>>
>>   Merge remote-tracking branch 'remotes/mcayland/tags/qemu-openbios-signed' 
>> into staging (2016-07-15 16:56:08 +0100)
>>
>> are available in the git repository at:
>>
>>   git://github.com/bonzini/qemu.git tags/for-upstream
>>
>> for you to fetch changes up to 6e5532eb16b1fcc7b6d5a15bc5fc0089c1f776f0:
>>
>>   block/iscsi: allow caching of the allocation map (2016-07-18 11:19:47 
>> +0200)
>>
>> ----------------------------------------------------------------
>> * tb_lock-less
>> * two old patches from prospective GSoC students
>> * i386 -kernel device tree support
>> * Coverity fix
>> * memory usage improvement from Peter
>> * checkpatch fix
>> * g_path_get_dirname cleanup
>> * caching of block status for iSCSI
>>
> 
> Hi. I'm afraid this fails to build on 32-bit:
> 
> In file included from /home/petmay01/qemu/include/qemu/osdep.h:36:0,
>                  from /home/petmay01/qemu/exec.c:19:
> /home/petmay01/qemu/include/exec/exec-all.h: In function 'tb_mark_invalid':
> /home/petmay01/qemu/include/qemu/compiler.h:85:23: error: size of
> array 'qemu_build_bug_on__265' is negative
>      typedef char glue(qemu_build_bug_on__,__LINE__)[(x)?-1:1]
> __attribute__((unused));
>                        ^
> /home/petmay01/qemu/include/qemu/compiler.h:50:21: note: in definition
> of macro 'xglue'
>  #define xglue(x, y) x ## y
>                      ^
> /home/petmay01/qemu/include/qemu/compiler.h:85:18: note: in expansion
> of macro 'glue'
>      typedef char glue(qemu_build_bug_on__,__LINE__)[(x)?-1:1]
> __attribute__((unused));
>                   ^
> /home/petmay01/qemu/include/qemu/atomic.h:63:5: note: in expansion of
> macro 'QEMU_BUILD_BUG_ON'
>      QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \
>      ^
> /home/petmay01/qemu/include/exec/exec-all.h:265:5: note: in expansion
> of macro 'atomic_set'
>      atomic_set(&tb->pc, pc);
>      ^
> /home/petmay01/qemu/include/qemu/compiler.h:85:23: error: size of
> array 'qemu_build_bug_on__266' is negative
>      typedef char glue(qemu_build_bug_on__,__LINE__)[(x)?-1:1]
> __attribute__((unused));
>                        ^
> /home/petmay01/qemu/include/qemu/compiler.h:50:21: note: in definition
> of macro 'xglue'
>  #define xglue(x, y) x ## y
>                      ^
> /home/petmay01/qemu/include/qemu/compiler.h:85:18: note: in expansion
> of macro 'glue'
>      typedef char glue(qemu_build_bug_on__,__LINE__)[(x)?-1:1]
> __attribute__((unused));
>                   ^
> /home/petmay01/qemu/include/qemu/atomic.h:63:5: note: in expansion of
> macro 'QEMU_BUILD_BUG_ON'
>      QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \
>      ^
> /home/petmay01/qemu/include/exec/exec-all.h:266:5: note: in expansion
> of macro 'atomic_set'
>      atomic_set(&tb->cs_base, cs_base);
>      ^
> 
> Looks like an attempt to do an atomic op on a larger-than-host-pointer type.

Hmm, atomic_set should be acceptable even on 64-bit.  I'll fix that up,
atomics are not necessary here because there's always a smp_wmb afterwards.

Paolo