From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCH v2 1/2] x86/VPMU: return correct fixed PMC count Date: Wed, 25 Nov 2015 14:32:40 -0500 Message-ID: <56560CD8.1000807@oracle.com> References: <1448409192-4914-1-git-send-email-bgregg@netflix.com> <1448409192-4914-2-git-send-email-bgregg@netflix.com> <565593A602000078000B8DF3@prv-mh.provo.novell.com> <5655C509.1040205@oracle.com> <5655E27802000078000B9139@prv-mh.provo.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5655E27802000078000B9139@prv-mh.provo.novell.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: Jan Beulich Cc: Brendan Gregg , dietmar.hahn@ts.fujitsu.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 11/25/2015 10:31 AM, Jan Beulich wrote: >> However, I just noticed that various control and status registers are >> not available for v1. I wonder whether we should even support version 1 >> since we'd need to add whole lot of 'if (supported)' throughout the code >> plus there are some assumptions about existence of IA32_PERF_GLOBAL_CTRL >> so we'll need to add additional logic to handle that too. And it's not >> clear to me if it's all worth it. > Indeed, let's not support v1 then for now and leave the exercise > to add all the if()s to whoever cares for such support. And, in fact, I think we should drop model check in core2_vpmu_init() and only test for PMU version. Especially in light of XSA-163. We could limit support to versions 2 and 3 only if we want to be on the safe side. If people agree I'll send a patch (on Monday). -boris