linux-kernel - Re: [Xen-devel] [PATCH v2] xen: Introduce 'xen_nopv' to disable PV extensions for HVM guests.

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Message-ID: <20140709135519.GB21837@laptop.dumpdata.com>
Date:	Wed, 9 Jul 2014 09:55:19 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	David Vrabel <david.vrabel@...rix.com>
Cc:	konrad@...nel.org, xen-devel@...ts.xenproject.org,
	boris.ostrovsky@...cle.com, linux-kernel@...r.kernel.org
Subject: Re: [Xen-devel] [PATCH v2] xen: Introduce 'xen_nopv' to disable PV
 extensions for HVM guests.

On Wed, Jul 09, 2014 at 01:10:03PM +0100, David Vrabel wrote:
> On 08/07/14 21:52, konrad@...nel.org wrote:
> > From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> > 
> > By default when CONFIG_XEN and CONFIG_XEN_PVHVM kernels are
> > run, they will enable the PV extensions (drivers, interrupts, timers,
> > etc) - which is perfect.
> 
> If it's "perfect" what's this option for? ;)

:-)
> 
> I think you mean to say "which is the best option for the majority of
> use cases".

Yes!
> 
> > However, in some cases (kexec not fully wokring, benchmarking)
> > we want to disable Xen PV extensions. As such introduce the
> > 'xen_nopv' parameter that will do it.
> 
> "working"
> 
> I'm unconvinced about the utility of this option.  The resulting kernel
> will go like molasses and I'm not sure what the use of being any to
> benchmark a configuration no one will use in practice.  But it's a small
> patch so
> 
> Reviewed-by: David Vrabel <david.vrabel@...rix.com>

Thank you.

> 
> David
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@...ts.xen.org
> http://lists.xen.org/xen-devel
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