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, URIBL_BLOCKED,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 7F2ECC2D0A3 for ; Tue, 3 Nov 2020 13:19:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3414221534 for ; Tue, 3 Nov 2020 13:19:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729161AbgKCNTB (ORCPT ); Tue, 3 Nov 2020 08:19:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729172AbgKCNTB (ORCPT ); Tue, 3 Nov 2020 08:19:01 -0500 Received: from theia.8bytes.org (8bytes.org [IPv6:2a01:238:4383:600:38bc:a715:4b6d:a889]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5546C0613D1 for ; Tue, 3 Nov 2020 05:19:00 -0800 (PST) Received: by theia.8bytes.org (Postfix, from userid 1000) id B0BA03A5; Tue, 3 Nov 2020 14:18:57 +0100 (CET) Date: Tue, 3 Nov 2020 14:18:52 +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: <20201103131852.GE22888@8bytes.org> References: <20201103095208.GA22888@8bytes.org> <20201103125643.GN2620339@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201103125643.GN2620339@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 08:56:43AM -0400, Jason Gunthorpe wrote: > On Tue, Nov 03, 2020 at 10:52:09AM +0100, joro@8bytes.org wrote: > > So having said this, what is the benefit of exposing those SVA internals > > to user-space? > > Only the device use of the PASID is device specific, the actual PASID > and everything on the IOMMU side is generic. > > There is enough API there it doesn't make sense to duplicate it into > every single SVA driver. What generic things have to be done by the drivers besides allocating/deallocating PASIDs and binding an address space to it? Is there anything which isn't better handled in a kernel-internal library which drivers just use? Regards, Joerg