From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 901B9C2BA16 for ; Wed, 8 Apr 2020 04:00:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6908020730 for ; Wed, 8 Apr 2020 04:00:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726492AbgDHEAW (ORCPT ); Wed, 8 Apr 2020 00:00:22 -0400 Received: from mga04.intel.com ([192.55.52.120]:12733 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725440AbgDHEAW (ORCPT ); Wed, 8 Apr 2020 00:00:22 -0400 IronPort-SDR: fcZA7fQERZUq2zf7yil4HR7pd4u9R4djaZni0CONZOlTJEIcLBamnKRzIKYp4up3gLulLaLQxs Hwx/mH9fvn8Q== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Apr 2020 21:00:21 -0700 IronPort-SDR: f9f374JUMkKx4uPk6CViWMoJ7usS0ImJsEAoos95KEZ8procvMO83u9Ez6k6bMdPzvgEpKaLQq uU7jtP826KNw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,357,1580803200"; d="scan'208";a="269639700" Received: from otc-nc-03.jf.intel.com (HELO otc-nc-03) ([10.54.39.25]) by orsmga002.jf.intel.com with ESMTP; 07 Apr 2020 21:00:21 -0700 Date: Tue, 7 Apr 2020 21:00:21 -0700 From: "Raj, Ashok" To: Alex Williamson Cc: "Tian, Kevin" , "Liu, Yi L" , "eric.auger@redhat.com" , "jacob.jun.pan@linux.intel.com" , "joro@8bytes.org" , "Tian, Jun J" , "Sun, Yi Y" , "jean-philippe@linaro.org" , "peterx@redhat.com" , "iommu@lists.linux-foundation.org" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Wu, Hao" , Bjorn Helgaas , Ashok Raj Subject: Re: [PATCH v1 2/2] vfio/pci: Emulate PASID/PRI capability for VFs Message-ID: <20200408040021.GS67127@otc-nc-03> References: <1584880394-11184-1-git-send-email-yi.l.liu@intel.com> <1584880394-11184-3-git-send-email-yi.l.liu@intel.com> <20200402165954.48d941ee@w520.home> <20200403112545.6c115ba3@w520.home> <20200407095801.648b1371@w520.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200407095801.648b1371@w520.home> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Alex + Bjorn FWIW I can't understand why PCI SIG went different ways with ATS, where its enumerated on PF and VF. But for PASID and PRI its only in PF. I'm checking with our internal SIG reps to followup on that. On Tue, Apr 07, 2020 at 09:58:01AM -0600, Alex Williamson wrote: > > Is there vendor guarantee that hidden registers will locate at the > > same offset between PF and VF config space? > > I'm not sure if the spec really precludes hidden registers, but the > fact that these registers are explicitly outside of the capability > chain implies they're only intended for device specific use, so I'd say > there are no guarantees about anything related to these registers. As you had suggested in the other thread, we could consider using the same offset as in PF, but even that's a better guess still not reliable. The other option is to maybe extend driver ops in the PF to expose where the offsets should be. Sort of adding the quirk in the implementation. I'm not sure how prevalent are PASID and PRI in VF devices. If SIG is resisting making VF's first class citizen, we might ask them to add some verbiage to suggest leave the same offsets as PF open to help emulation software. > > FWIW, vfio started out being more strict about restricting config space > access to defined capabilities, until... > > commit a7d1ea1c11b33bda2691f3294b4d735ed635535a > Author: Alex Williamson > Date: Mon Apr 1 09:04:12 2013 -0600 > Cheers, Ashok