[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 04/13] xen: sync public headers
> -----Original Message----- > From: Tim Deegan [mailto:tim@xxxxxxx] > Sent: 08 February 2013 16:50 > To: Paul Durrant > Cc: Ian Campbell; xen-devel@xxxxxxxxxxxxx; Wei Liu; David Vrabel; > jbeulich@xxxxxxxx; Konrad Rzeszutek Wilk > Subject: Re: [Xen-devel] [PATCH 04/13] xen: sync public headers > > At 16:36 +0000 on 08 Feb (1360341398), Paul Durrant wrote: > > > > > > > > I don't think so. The reason to use unsigned long here is > > > > > > > > to guarantee each selector (in 2-level case there is only > > > > > > > > L1 > > > > > > > > selector) fits into a word. > > > > > > > > > > > > > > > > > > > That's still going to be a problem with Windows drivers. > > > > > > Unfortunately > > > > > MSVC uses a 64-bit model where longs are still 32-bit. The only > > > > > thing that is word size is a pointer. Any chance we can use > > > > > uintptr_t rather than an unsigned long? (At the moment I have to > > > > > sed all the public headers to replace long with LONG_PTR and it's a > PITA). > > > > > > > > > > > > > > > > TBH I don't know much about Windows. But are you suggesting > > > > > replace all the relevant bit in the header or just the specific > > > > > event channel > > > interface? > > > > > > > > > > > > > I was just pointing out that assumption that unsigned long == > > > > native word size does not hold for 64-bit Windows. So, if we're > > > > adding something new can we avoid use of unsigned long and use an > > > > abstract type defined to be the native word size? > > > > > > Probably ought to be the existing xen_ulong_t. > > > > That works for me :-) > > Hmm. xen_ulong_t is a typedef for unsigned long on x86. Are you > suggesting we change that? On the grounds that any platform where it > would make a difference to the ABI has already had to adjust its headers? I > think I can buy that. > Yes, the crux of the issue is what *is* an unsigned long? If Xen uses one model and the guest OS uses a different one then use of non-abstract types in the public headers becomes awkward. Paul _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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