Re: [PATCH 3/4] PF: Provide additional direct page notification

[Gleb Natapov]

On Wed, Jul 10, 2013 at 12:45:59PM +0200, Alexander Graf wrote:
> 
> On 10.07.2013, at 12:42, Gleb Natapov wrote:
> 
> > On Wed, Jul 10, 2013 at 12:39:01PM +0200, Alexander Graf wrote:
> >> 
> >> On 09.07.2013, at 18:01, Christian Borntraeger wrote:
> >> 
> >>> On 09/07/13 15:56, Dominik Dingel wrote:
> >>>> By setting a Kconfig option, the architecture can control when
> >>>> guest notifications will be presented by the apf backend.
> >>>> So there is the default batch mechanism, working as before, where the vcpu thread
> >>>> should pull in this information. On the other hand there is now the direct
> >>>> mechanism, this will directly push the information to the guest.
> >>>> 
> >>>> Still the vcpu thread should call check_completion to cleanup leftovers,
> >>>> that leaves most of the common code untouched.
> >>>> 
> >>>> Signed-off-by: Dominik Dingel <dingel@xxxxxxxxxxxxxxxxxx>
> >>> 
> >>> Acked-by: Christian Borntraeger <borntraeger@xxxxxxxxxx> 
> >>> for the "why". We want to use the existing architectured interface.
> >> 
> >> Shouldn't this be a runtime option?
> >> 
> > Why? What is the advantage of using sync delivery when HW can do it
> > async?
> 
> What's the advantage of having an option at all then? Who selects it?
> 
x86 is stupid and cannot deliver the even asynchronously. Platform that
can do it select the option.

--
			Gleb.
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