From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: Is: axe read_tscp pvops call. Was: Re: [RFC] ACPI S3 and Xen (suprisingly small\!). Date: Wed, 17 Oct 2012 12:54:52 -0400 Message-ID: <20121017165452.GA22740@phenom.dumpdata.com> References: <1350481786-4969-1-git-send-email-konrad.wilk@oracle.com> <507ED6C0.4020503@zytor.com> <20121017161036.GA10691@phenom.dumpdata.com> <507EE1C3.7070300@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <507EE1C3.7070300@zytor.com> Sender: linux-kernel-owner@vger.kernel.org To: "H. Peter Anvin" Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, lenb@kernel.org, linux-acpi@vger.kernel.org, x86@kernel.org List-Id: xen-devel@lists.xenproject.org On Wed, Oct 17, 2012 at 09:50:11AM -0700, H. Peter Anvin wrote: > On 10/17/2012 09:10 AM, Konrad Rzeszutek Wilk wrote: > >On Wed, Oct 17, 2012 at 09:03:12AM -0700, H. Peter Anvin wrote: > >>On 10/17/2012 06:49 AM, Konrad Rzeszutek Wilk wrote: > >>> > >>>Note: These are the other patches that went in 3.7-rc1: > >>>xen/bootup: allow {read|write}_cr8 pvops call [https://lkml.org/lkml/2012/10/10/339] > >>>xen/bootup: allow read_tscp call for Xen PV guests. [https://lkml.org/lkml/2012/10/10/340] > >>> > >> > >>So WTF do we have a read_tscp PV call? Again, if there isn't a user > >>we should just axe it... > > > >Let me spin off a patch to see if that can be done. > > > > Could you do an audit for other pvops calls that have no users? If > the *only* user is lguest, we should talk about it, too... I can do that - but I don't want to be hasty here. There is a bit of danger here - for example the read_pmc (or read_tsc) is not in use right now. But it might be when one starts looking at making perf be able to analyze the hypervisor (hand-waving the implementation details). So while removing read_pmc now sounds good, it might be needed in the future. Or maybe not :-) Let me do a candidate list and get some conversation going.