From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH for-4.6] p2m/ept: Set the A bit only if PML is enabled Date: Wed, 23 Sep 2015 11:28:33 -0400 Message-ID: <20150923152832.GA3441@konrad-lan.dumpdata.com> References: <1442393271-12388-1-git-send-email-ross.lagerwall@citrix.com> <20150923151846.GA9208@zion.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20150923151846.GA9208@zion.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Wei Liu Cc: Jun Nakajima , Kevin Tian , Keir Fraser , Eddie Dong , George Dunlap , Andrew Cooper , tim@xen.org, xen-devel@lists.xen.org, Kai Huang , Ross Lagerwall , Jan Beulich List-Id: xen-devel@lists.xenproject.org On Wed, Sep 23, 2015 at 04:18:46PM +0100, Wei Liu wrote: > With the discussion still not finalised I'm a bit worried that this > issue will block the release. > > I think we have a few options here. I will list them in order of my > preference. Please correct me if I'm talking non-sense, and feel free to > add more options if I miss anything. > > 1. Disable PML on broken chips, gate access to A bit (or AD) with PML. > > In the sub-thread I had with Ross, the proposed patch already does that. > There is no need to "disable PML in broken chips" because that feature > is not supported by broken chips in the first place. > > The downside is that the overhead of gating with `if' statement which > makes things a tad slower for everyone. But that's not really reason to > reject this patch because any gating method would involve similar > overhead. One could use alternative assembler for this.