Re: [Qemu-devel] [PULL 3/8] vfio: Generalize region support

[Eric Blake]

On 03/10/2016 09:34 AM, Alex Williamson wrote:

>>> +            trace_vfio_msix_fixup(vdev->vbasedev.name,
>>> +                              vdev->msix->table_bar, 
>>> region->mmaps[0].offset,
>>> +                              region->mmaps[0].offset + 
>>> region->mmaps[0].size);  
>> Sorry this does not compile for me on arm 32b:
>>
>> ./trace/generated-tracers.h:16113:23: error: format ‘%lx’ expects
>> argument of type ‘long unsigned int’, but argument 8 has type ‘off_t’
>> [-Werror=format=] , name, bar, offset, size);
>>
>> -> vfio_msix_fixup(const char *name, int bar, off_t start, off_t end) "  
>> (%s) MSI-X region %d mmap fixup [0x%"PRIx64" - 0x%"PRIx64"]" ?
> 

>  vfio_msix_disable(const char *name) " (%s)"
> -vfio_msix_fixup(const char *name, int bar, off_t offset, size_t size) " (%s) 
> MSI-X region %d mmap fixup [0x%lx - 0x%lx]"
> +vfio_msix_fixup(const char *name, int bar, off_t start, off_t end) " (%s) 
> MSI-X region %d mmap fixup [0x%"PRIx64" - 0x%"PRIx64"]"

off_t and PRIx64 are not necessarily compatible types (on a 64-bit
platform, one could be 'long' while the other is 'long long').  And even
though we set compiler flags to get 64-bit off_t on 32-bit platforms,
your code is not portable to people that don't set those flags and are
stuck with 32-bit off_t.

It may be better to declare start and end as [u]int64_t, rather than off_t.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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