Re: [PATCH 4/8] unify paravirt parts of system.h

[Denys Vlasenko <vda.linux@googlemail.com>]

On Tuesday 04 December 2007 11:41, Glauber de Oliveira Costa wrote:
> On Dec 4, 2007 5:18 PM, Avi Kivity <avi@qumranet.com> wrote:
> > There is no cr8 register on i386.  This had better be protected by an
> > #ifdef.
>
> Sure. I mentioned it in the changelog. I, however, am not sure If I
> agree it should be enclosed
> in ifdefs. Me and Jeremy discussed it a while ago, and we seem to
> agree that for those functions
> that are exclusive of one architecture, there were no need for ifdefs.
> Any usage by the other arch
> is a bug.
>
> But I admit that I'm not particularly biased here, and I can change
> it, if there's agreement that
> an ifdef here is the way to go.
>
> > (you're likely not getting an error since it's a static inline, so the
> > asm is never emitted)
>
> Which also means it does not affect the binary in anyway. No bigger
> code, no nothing.

If future changes will mistakenly make 32-bit x86 call native_read_cr8(),
you will get no warning. (Hmmm. Maybe as will complain, I'm not sure).
If it explicitly ifdefed out for 32 bits, it's easier to detect misuse.
--
vda