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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DF038C678D5 for ; Wed, 15 Feb 2023 21:02:26 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pSOuq-0007Rp-Kr; Wed, 15 Feb 2023 16:02:13 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pSOum-0007QX-9C for qemu-devel@nongnu.org; Wed, 15 Feb 2023 16:02:08 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pSOuj-0001Q7-Na for qemu-devel@nongnu.org; Wed, 15 Feb 2023 16:02:07 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1676494924; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TnJ3fSSd8S6K2YvOX3X1SKBTQibopmzhwZOmYFfZ8cA=; b=MJbCcuvqr8bulOGaA5yKlMjEh56h+oItvKbG5OkhRAI8/xp5CXesYCacx33oOBv7EDolk+ MsER3aNejvvVc2QlGRN0IWBtTxgERYoh0TGnCt4I5lwWBmMrzQ3rZypXpiceHuDO6Z7EYa mneNZt80vAQQ5uExSmrjo5OTfat/eRA= Received: from mail-io1-f72.google.com (mail-io1-f72.google.com [209.85.166.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-223-19KnK4yNPLeGZATZjmU9rQ-1; Wed, 15 Feb 2023 16:02:03 -0500 X-MC-Unique: 19KnK4yNPLeGZATZjmU9rQ-1 Received: by mail-io1-f72.google.com with SMTP id n3-20020a056602340300b0073e7646594aso6248058ioz.8 for ; Wed, 15 Feb 2023 13:02:03 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=TnJ3fSSd8S6K2YvOX3X1SKBTQibopmzhwZOmYFfZ8cA=; b=unPbLqctbnQxd/rnlc947nonOsa3TIJLoJ17Dvx+MhV8h9g34zuXFy/rIMUnUnr/v+ GSf+16A5jf/TjeXpstQ0RYYXmeVzhSu2iIZJKwHhERBoaTjn01SJsG5l+oOcZ10at9uk j7LVqhPNx8lMt1AtpEDeGBS88bCeeRbYdy6TV1daJ2hIUcAcWCESknzqIO2U65PI/SSB 8+/TxnaMEOGtjNL3xPrUOIClLkI9M6GJkc4kVp8PTJS2xKOXASFc93APFvzDIlUAU2oS q1+lKWWNjqy6NTvEh4+natwBjhxTL/bTlYSOw6/qrhlxwz8nXqPIjHZkDkW0HI8Zs8ho UslQ== X-Gm-Message-State: AO0yUKWtxoT+yeFCNJZ/mDw58bn48tdt1ZUCTmENUzbCNAPpj90E9YKU GaOIxHbmAoGghwm/t49QkUcypN1zv0Qvg5spKUpr/KYhARPhNjoe2+at1ox53uj1K5+aDoZdxFo 2D+s33elqLpKPq6k= X-Received: by 2002:a92:c548:0:b0:315:3b69:7f74 with SMTP id a8-20020a92c548000000b003153b697f74mr3414356ilj.23.1676494922586; Wed, 15 Feb 2023 13:02:02 -0800 (PST) X-Google-Smtp-Source: AK7set+INYBHMMMpFimck7EE0W8tYzBm5t55mb2QA3RUhrHVYQGTLV/JCdLFd+Dxt+Kyo+YEO7zSmg== X-Received: by 2002:a92:c548:0:b0:315:3b69:7f74 with SMTP id a8-20020a92c548000000b003153b697f74mr3414339ilj.23.1676494922287; Wed, 15 Feb 2023 13:02:02 -0800 (PST) Received: from redhat.com ([38.15.36.239]) by smtp.gmail.com with ESMTPSA id l25-20020a02cd99000000b003a9632cb099sm1618456jap.51.2023.02.15.13.02.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Feb 2023 13:02:01 -0800 (PST) Date: Wed, 15 Feb 2023 14:02:00 -0700 From: Alex Williamson To: Jason Gunthorpe Cc: Juan Quintela , Avihai Horon , qemu-devel@nongnu.org, "Dr. David Alan Gilbert" , "Michael S. Tsirkin" , Cornelia Huck , Paolo Bonzini , Vladimir Sementsov-Ogievskiy , =?UTF-8?B?Q8OpZHJpYw==?= Le Goater , Yishai Hadas , Maor Gottlieb , Kirti Wankhede , Tarun Gupta , Joao Martins Subject: Re: [PATCH v10 03/12] vfio/migration: Allow migration without VFIO IOMMU dirty tracking support Message-ID: <20230215140200.19b6e308.alex.williamson@redhat.com> In-Reply-To: References: <20230209192043.14885-1-avihaih@nvidia.com> <20230209192043.14885-4-avihaih@nvidia.com> <8735773xr7.fsf@secure.mitica> <2efede77-0b06-0efa-1ea2-86300307c86f@nvidia.com> <87sff6ztxq.fsf@secure.mitica> <20230215131435.3e14aa55.alex.williamson@redhat.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.35; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=alex.williamson@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, 15 Feb 2023 16:38:10 -0400 Jason Gunthorpe wrote: > On Wed, Feb 15, 2023 at 01:14:35PM -0700, Alex Williamson wrote: > > > We'll need to consider whether we want to keep "dumb" dirty tracking, > > or even any form of dirty tracking in the type1 uAPI, under an > > experimental opt-in. Thanks, > > I was expecting we'd delete the kernel code for type 1 dirty tracking > once the v2 parts are merged to qemu since we don't and won't have any > kernel implementation of it.. > > The big point of this to allow qmeu to continue on with a future > kernel that no longer reports it supports this. Right, in the part-1 series adding v2 support, we have no other dirty tracking, so it serves a purpose until we have device-level dirty tracking in the part-2 series. After that, we can certainly at least remove the type1 dirty tracking since there never were, and likely never will be, any in-kernel implementations. I could go either way if we want to keep the in-QEMU dirty-everything tracking around as an experimental option to aid migration driver development/debug (ie. maybe enabling it preempts device dirty tracking as a comparison for debug). Thanks, Alex