From patchwork Fri Feb 23 07:27:22 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Auger X-Patchwork-Id: 13568593 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 D9829C5478C for ; Fri, 23 Feb 2024 07:46:16 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rdQFN-0001J5-Dt; Fri, 23 Feb 2024 02:45:29 -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 1rdQFC-00018K-Jr for qemu-devel@nongnu.org; Fri, 23 Feb 2024 02:45:18 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rdQF7-0004ww-Gj for qemu-devel@nongnu.org; Fri, 23 Feb 2024 02:45:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1708674311; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=zRYLunAOikJyU8BvGCpMGX9MHgMaFjOhFKeLKz55XSg=; b=YKKuU6vIXjBf4sJSSN5JRpFwEG9e85ticTYJB9tpDY1Tvz5eRtxdO6fC8ozVT9ELpUnf7J od/lgLXcHiEPJV5x+NynBKcxB574qljlGNVFM5bHLN8hhcnWvPH4bHKoqk+5SxMySe0aKC t3oUM1vj68z8KSmHn9GtPSfLi9iat68= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-98-58KWq9DUMbCbCQ2mxOQJrQ-1; Fri, 23 Feb 2024 02:45:05 -0500 X-MC-Unique: 58KWq9DUMbCbCQ2mxOQJrQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D67DA83B825; Fri, 23 Feb 2024 07:45:04 +0000 (UTC) Received: from laptop.redhat.com (unknown [10.39.195.78]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7A84D40D1B67; Fri, 23 Feb 2024 07:45:01 +0000 (UTC) From: Eric Auger To: eric.auger.pro@gmail.com, eric.auger@redhat.com, qemu-devel@nongnu.org, qemu-arm@nongnu.org, mst@redhat.com, jean-philippe@linaro.org, peter.maydell@linaro.org, clg@redhat.com, yanghliu@redhat.com Cc: alex.williamson@redhat.com, zhenzhong.duan@intel.com, jasowang@redhat.com, pbonzini@redhat.com, berrange@redhat.com Subject: [PATCH v4 0/3] VIRTIO-IOMMU: Set default granule to host page size Date: Fri, 23 Feb 2024 08:27:22 +0100 Message-ID: <20240223074459.63422-1-eric.auger@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 Received-SPF: pass client-ip=170.10.133.124; envelope-from=eric.auger@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=-0.002, 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable 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 We used to set the default granule to 4KB but with VFIO assignment it makes more sense to use the actual host page size. Indeed when hotplugging a VFIO device protected by a virtio-iommu on a 64kB/64kB host/guest config, we currently get a qemu crash: "vfio: DMA mapping failed, unable to continue" This is due to the hot-attached VFIO device calling memory_region_iommu_set_page_size_mask() with 64kB granule whereas the virtio-iommu granule was already frozen to 4KB on machine init done. Introduce a new granule property and set this latter to "host" and introduce a new compat. Note that the new default will prevent 4kB guest on 64kB host because the granule will be set to 64kB which would be larger than the guest page size. In that situation, the virtio-iommu driver fails on viommu_domain_finalise() with "granule 0x10000 larger than system page size 0x1000". In that case 4K granule should be used. To summarize, before the series, the support matrix (credit to Jean-Philippe Brucker) was: Host | Guest | virtio-net | IGB passthrough 4k | 4k | Y | Y 64k | 64k | Y | N 64k | 4k | Y | N 4k | 64k | Y | Y After the series: Host | Guest | virtio-net | IGB passthrough 4k | 4k | Y | Y 64k | 64k | Y | Y 64k | 4k | 4K | N 4k | 64k | Y | Y The current limitation of global granule in the virtio-iommu should be removed and turned into per domain granule. But until we get this upgraded, this new default is probably better because I don't think anyone is currently interested in running a 4KB page size guest with virtio-iommu on a 64KB host. However supporting 64kB guest on 64kB host with virtio-iommu and VFIO looks a more important feature. This series can be found at: https://github.com/eauger/qemu/tree/granule-v2 Applied on top of [PATCH v5 0/4] VIRTIO-IOMMU: Introduce an aw-bits option https://lore.kernel.org/all/20240215084315.863897-1-eric.auger@redhat.com/ History: v3 -> v4: - Add 8K granule (Richard) v2 -> v3 - introduce a dedicated granule option to handle the compat Eric Auger (3): qdev: Add a granule_mode property virtio-iommu: Add a granule property virtio-iommu: Change the default granule to the host page size include/hw/qdev-properties-system.h | 3 +++ include/hw/virtio/virtio-iommu.h | 12 +++++++++ hw/core/machine.c | 1 + hw/core/qdev-properties-system.c | 15 ++++++++++++ hw/virtio/virtio-iommu.c | 38 ++++++++++++++++++++++++++--- qemu-options.hx | 3 +++ 6 files changed, 69 insertions(+), 3 deletions(-)