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=-5.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 B9AFCC49EA7 for ; Thu, 24 Jun 2021 04:53:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A4A31613EC for ; Thu, 24 Jun 2021 04:53:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230239AbhFXEyz (ORCPT ); Thu, 24 Jun 2021 00:54:55 -0400 Received: from bilbo.ozlabs.org ([203.11.71.1]:58469 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229448AbhFXEyu (ORCPT ); Thu, 24 Jun 2021 00:54:50 -0400 Received: by ozlabs.org (Postfix, from userid 1007) id 4G9SRT58RKz9t0p; Thu, 24 Jun 2021 14:52:21 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1624510341; bh=Sm55XzzGfIQHnANDiUMDuvbZ7IYjUCtojFRRcEiqmdw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZuxeZjTQrfzT56BXV29tLxlyIOHOXy7GQrcr5dBHMdRwtRLepAJHBZ5QOStm+KtB9 y/cqy+JBpGt3PhpRnK8A4w9a+1QeLo6AY7yDNB6p+zQ7fzd3+URtYF1LoCqsBD7qyE RJM+qZc3B2GADxb/auGsSb1b+o/5v4GHaOrRSSXE= Date: Thu, 24 Jun 2021 14:37:31 +1000 From: David Gibson To: Jason Gunthorpe Cc: Alex Williamson , Joerg Roedel , "Tian, Kevin" , Jean-Philippe Brucker , Jason Wang , "parav@mellanox.com" , "Enrico Weigelt, metux IT consult" , Paolo Bonzini , Shenming Lu , Eric Auger , Jonathan Corbet , "Raj, Ashok" , "Liu, Yi L" , "Wu, Hao" , "Jiang, Dave" , Jacob Pan , Kirti Wankhede , Robin Murphy , "kvm@vger.kernel.org" , "iommu@lists.linux-foundation.org" , David Woodhouse , LKML , Lu Baolu Subject: Re: Plan for /dev/ioasid RFC v2 Message-ID: References: <20210609123919.GA1002214@nvidia.com> <20210609150009.GE1002214@nvidia.com> <20210609101532.452851eb.alex.williamson@redhat.com> <20210617230438.GZ1002214@nvidia.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="yoFsgJzPurSq8+17" Content-Disposition: inline In-Reply-To: <20210617230438.GZ1002214@nvidia.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org --yoFsgJzPurSq8+17 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 17, 2021 at 08:04:38PM -0300, Jason Gunthorpe wrote: > On Thu, Jun 17, 2021 at 03:02:33PM +1000, David Gibson wrote: >=20 > > In other words, do we really have use cases where we need to identify > > different devices IDs, even though we know they're not isolated. >=20 > I think when PASID is added in and all the complexity that brings, it > does become more important, yes. >=20 > At the minimum we should scope the complexity. >=20 > I'm not convinced it is so complicated, really it is just a single bit > of information toward userspace: 'all devices in this group must use > the same IOASID' Um.. no? You could have devA and devB sharing a RID, but then also sharing a group but not a RID with devC because of different isolation issues. So you now have (at least) two levels of group structure to expose somehow. >=20 > Something like qemu consumes this bit and creates the pci/pcie bridge > to model this to the guest and so on. >=20 > Something like dpdk just doesn't care (same as today). >=20 > Jason >=20 --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --yoFsgJzPurSq8+17 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEdfRlhq5hpmzETofcbDjKyiDZs5IFAmDUDAsACgkQbDjKyiDZ s5K4XA//Y4QIGGAGVVbJfKrlf5JkN2/2a7VHx4vaUfc4NR5mVhkNYwvGbSYutZQ7 AjjTm5pfpoAem4nB8Q6U3GfaFTsj2YUg6Vodt8xJhSilvNHENa04nCVQMhACfYUn SaQAMbx4gnuxaL02rl5NzWe5u5j1Vm1L485cfpMvdDae0Huq4qiMV4zCASCxGkO3 vIRkdPSdp8legFimjVdQJPLVnAIFG1nJk/9toYcNpXp0esbOxYMHszvcXkMM3F2l 1qyY4HbXOHBGQTvuAAAATYZve/p9YqYQ8ePzuYuLo8q4HAzL3V1uB9Dy9sGgXhFL g46MfO3FKjnjrMxpanmv6ztsnoY4WOxMJundhPQ1ANayPNAPVSn3KaCSzX7hcfQH xSOX8kjr5RDi1F3BYKPmOOGRK0dmGMRaWlCapWSLkobKzUUAaUT43jMa2843gP9O b9PSXzODLGUu3fIUITRoMLGI881jigBWg/gmtV1egbi0s/qngiheJFzP9mptbzfw eciggSqjH/4ZBuBpRhNDnICQNNF/39/r9qOeWeiBicfW+8HciMvcsjvcWVgOnAhl /nIFGSMu6uTSWnSP6WR4fYDy7WRlsQM+GUk58WekBW19yzvoaoubmBXRCHq5eHmF hKf3A9OxFZRJNs0G8wp6e6R3RSp67s+4+AUyEmEdzsJ6863Z9xw= =1/9P -----END PGP SIGNATURE----- --yoFsgJzPurSq8+17--