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=-5.2 required=3.0 tests=BAYES_00, 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 7C41EC388F9 for ; Tue, 3 Nov 2020 14:05:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 35C6422243 for ; Tue, 3 Nov 2020 14:05:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729493AbgKCOFC (ORCPT ); Tue, 3 Nov 2020 09:05:02 -0500 Received: from 8bytes.org ([81.169.241.247]:39188 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729361AbgKCODU (ORCPT ); Tue, 3 Nov 2020 09:03:20 -0500 X-Greylist: delayed 2662 seconds by postgrey-1.27 at vger.kernel.org; Tue, 03 Nov 2020 09:03:20 EST Received: by theia.8bytes.org (Postfix, from userid 1000) id A00FD433; Tue, 3 Nov 2020 15:03:19 +0100 (CET) Date: Tue, 3 Nov 2020 15:03:18 +0100 From: "joro@8bytes.org" To: Jason Gunthorpe Cc: "Tian, Kevin" , Jason Wang , "Liu, Yi L" , "alex.williamson@redhat.com" , "eric.auger@redhat.com" , "baolu.lu@linux.intel.com" , "jacob.jun.pan@linux.intel.com" , "Raj, Ashok" , "Tian, Jun J" , "Sun, Yi Y" , "jean-philippe@linaro.org" , "peterx@redhat.com" , "Wu, Hao" , "stefanha@gmail.com" , "iommu@lists.linux-foundation.org" , "kvm@vger.kernel.org" , "Michael S. Tsirkin" Subject: Re: (proposal) RE: [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs Message-ID: <20201103140318.GL22888@8bytes.org> References: <20201103095208.GA22888@8bytes.org> <20201103125643.GN2620339@nvidia.com> <20201103131852.GE22888@8bytes.org> <20201103132335.GO2620339@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201103132335.GO2620339@nvidia.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Nov 03, 2020 at 09:23:35AM -0400, Jason Gunthorpe wrote: > Userspace needs fine grained control over the composition of the page > table behind the PASID, 1:1 with the mm_struct is only one use case. VFIO already offers an interface for that. It shouldn't be too complicated to expand that for PASID-bound page-tables. > Userspace needs to be able to handle IOMMU faults, apparently Could be implemented by a fault-fd handed out by VFIO. > The Intel guys had a bunch of other stuff too, looking through the new > API they are proposing for vfio gives some flavour what they think is > needed.. I really don't think that user-space should have to deal with details like PASIDs or other IOMMU internals, unless absolutly necessary. This is an OS we work on, and the idea behind an OS is to abstract the hardware away. Regards, Joerg