Messages in this thread | | | From | Linus Torvalds <> | Date | Fri, 30 Nov 2012 09:01:50 -0800 | Subject | Re: [PATCH 8/8] x86, cleanups: Simplify sync_core() in the case of no CPUID |
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On Thu, Nov 29, 2012 at 1:24 PM, H. Peter Anvin <hpa@linux.intel.com> wrote: > > Thinking about it some more, there is another reason to not do this, > which is that we don't want this particular CPUID to be paravirtualized; > we're after the synchronizing side effect, not the CPUID return value > itself. > > So let's leave it as a primitive; it gets too confusing otherwise.
Hmm. The virtualization issue brings up another point: do we *really* want to use cpuid for serialization at all?
Exactly because under _real_ virtualization (as opposed to para-virt), it can cause unnecessary exits in a virtualized environment, no?
So I'm wondering if there is any better synchronizing instruction..
I guess sync_core() isn't used *that* much, so maybe we don't care, but I thought I'd ask...
Linus
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