From patchwork Tue Jan 23 18:15:54 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Auger X-Patchwork-Id: 13527949 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 0764FC47DDB for ; Tue, 23 Jan 2024 18:19:18 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rSLLj-00078c-2p; Tue, 23 Jan 2024 13:18:15 -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 1rSLLa-0006y3-Dt for qemu-devel@nongnu.org; Tue, 23 Jan 2024 13:18:06 -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 1rSLLX-00063I-GZ for qemu-devel@nongnu.org; Tue, 23 Jan 2024 13:18:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1706033882; 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=nUqVILcn7AB2FN5KpSvA8iJREURVQcQkUzfoeXjf0Bo=; b=iRVu2eF7qRFwsuVOLwIr1MWqshZa4C3GO4xlbiZP/2JwyqR8Mcg9xQV8cOkVZuxB/ZydnO 3xmNOUuDPI23hldHXYxemvy6u5HRC+sEgtYHXqWQJfn3/5pS36+2bZZ5jSmVtQp4KxuTgi 0XY7uMwBh0HYymPtIn7wqyaQOmUu+OQ= 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-428-cpCXdbAaNZulB51rsLWajA-1; Tue, 23 Jan 2024 13:17:59 -0500 X-MC-Unique: cpCXdbAaNZulB51rsLWajA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (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 AB95E85A589; Tue, 23 Jan 2024 18:17:58 +0000 (UTC) Received: from laptop.redhat.com (unknown [10.39.192.75]) by smtp.corp.redhat.com (Postfix) with ESMTP id 369EA2166B32; Tue, 23 Jan 2024 18:17:56 +0000 (UTC) From: Eric Auger To: eric.auger.pro@gmail.com, eric.auger@redhat.com, qemu-devel@nongnu.org, qemu-arm@nongnu.org, jean-philippe@linaro.org, alex.williamson@redhat.com, peter.maydell@linaro.org, zhenzhong.duan@intel.com, peterx@redhat.com, yanghliu@redhat.com Cc: mst@redhat.com, clg@redhat.com, jasowang@redhat.com Subject: [PATCH 0/3] VIRTIO-IOMMU: Introduce an aw-bits option Date: Tue, 23 Jan 2024 19:15:54 +0100 Message-ID: <20240123181753.413961-1-eric.auger@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.6 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: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.327, 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_H3=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=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 In [1] and [2] we attempted to fix a case where a VFIO-PCI device protected with a virtio-iommu is assigned to an x86 guest. On x86 the physical IOMMU may have an address width (gaw) of 39 or 48 bits whereas the virtio-iommu exposes a 64b input address space by default. Hence the guest may try to use the full 64b space and DMA MAP failures may be encountered. To work around this issue we endeavoured to pass usable host IOVA regions (excluding the out of range space) from VFIO to the virtio-iommu device so that the virtio-iommu driver can query those latter during the probe request and let the guest iommu kernel subsystem carve them out. However if there are several devices in the same iommu group, only the reserved regions of the first one are taken into account by the iommu subsystem of the guest. This generally works on baremetal because devices are not going to expose different reserved regions. However in our case, this may prevent from taking into account the host iommu geometry. So the simplest solution to this problem looks to introduce an input address width option, aw-bits, which matches what is done on the intel-iommu. By default, from now on it is set to 39 bits with pc_q35 and 64b with arm virt. This replaces the previous default value of 64b. So we need to introduce a compat for pc_q35 machines older than 9.0 to behave similarly. Outstanding series [2] remains useful to let resv regions beeing communicated on time before the probe request. [1] [PATCH v4 00/12] VIRTIO-IOMMU/VFIO: Don't assume 64b IOVA space https://lore.kernel.org/all/20231019134651.842175-1-eric.auger@redhat.com/ - This is merged - [2] [RFC 0/7] VIRTIO-IOMMU/VFIO: Fix host iommu geometry handling for hotplugged devices https://lore.kernel.org/all/20240117080414.316890-1-eric.auger@redhat.com/ - This is pending for review on the ML - This series can be found at: https://github.com/eauger/qemu/tree/virtio-iommu-aw-bits-v1 Applied on top of [3] [PATCH v2] virtio-iommu: Use qemu_real_host_page_mask as default page_size_mask https://lore.kernel.org/all/20240117132039.332273-1-eric.auger@redhat.com/ Eric Auger (3): virtio-iommu: Add an option to define the input range width virtio-iommu: Trace domain range limits as unsigned int hw/pc: Set the default virtio-iommu aw-bits to 39 on pc_q35_9.0 onwards include/hw/virtio/virtio-iommu.h | 1 + hw/arm/virt.c | 6 ++++++ hw/i386/pc.c | 10 +++++++++- hw/virtio/virtio-iommu.c | 4 +++- hw/virtio/trace-events | 2 +- 5 files changed, 20 insertions(+), 3 deletions(-)