Re: [PATCH] x86: svm: make wbinvd faster

[Marcelo Tosatti]

On Tue, Mar 10, 2015 at 12:01:31PM +0100, Radim KrÄmÃÅ wrote:
> 2015-03-09 20:28-0300, Marcelo Tosatti:
> > On Fri, Feb 27, 2015 at 06:19:18PM -0600, Joel Schopp wrote:
> > > From: David Kaplan <David.Kaplan@xxxxxxx>
> > > No need to re-decode WBINVD since we know what it is from the intercept.
> > > 
> > > Signed-off-by: David Kaplan <David.Kaplan@xxxxxxx>
> > > [extracted from larger unlrelated patch, forward ported, tested]
> > > Signed-off-by: Joel Schopp <joel.schopp@xxxxxxx>
> > 
> > Can't you disable the intercept if need_emulate_wbinvd(vcpu) == false? 
> 
> I don't think we want to:  it should be faster to intercept and ignore
> than to invalidate all caches.  The exit doesn't affect other physical
> cores and costs just about 10(?) L3 cache misses.

Yes, right.

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