lkml.org 
[lkml]   [2007]   [Jul]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [GIT PULL][RESEND #2] KVM Updates for 2.6.23-rc1


On Tue, 17 Jul 2007, H. Peter Anvin wrote:
>
> S.Çağlar Onur wrote:
> >
> > If i'm not wrong X86_CMPXCHG64 depends on CONFIG_X86_PAE which depends on
> > HIGHMEM64 and again if i'm not wrong this means distributions who wants to
> > provide KVM must enable CONFIG_X86_PAE and CONFIG_HIGHMEM64G from now on?
> >
>
> X86_PAE should depend on X86_CMPXCHG64, not the other way around.

Actually, I think the *real* solution would be:

- add a X86_HAS_CMPXCHG8B config option, and set it for the appropriate
CPU selection (P6 and up, or whatever the rule is)

- make KVM depend on it

- make KVM and HIGHMEM64 _select_ another config option, namely the
NEEDS_CMPXCHG8B

and then we make the cpufeatures code check the CMPXCHG bit only if the
NEEDS_CMPXCHG8B thing is set. That gives us the best of all worlds.

Because there is no point in checking whether the CPU supports it if the
kernel doesn't _need_ it. Especially since we know that some CPU's lie
about it due to old NT bugs.

Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-07-17 21:19    [W:0.041 / U:0.308 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site