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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 20718C433DB for ; Fri, 15 Jan 2021 04:48:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D56E223107 for ; Fri, 15 Jan 2021 04:48:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730230AbhAOEs1 (ORCPT ); Thu, 14 Jan 2021 23:48:27 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:56183 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727903AbhAOEs0 (ORCPT ); Thu, 14 Jan 2021 23:48:26 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610686019; 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=5qlVp+V62hJFOmojeKBtO6bnSDZxjgJebYHvIlsbcQM=; b=B+w76z7Lex0cFEQnQSBvlE5nhM3X4NJTL6P5z1S9MHhVZs4pBJ6dAoGY0CD6+X8766LHNz ajJUoJk6hEALN/Me+X0sQ0h9kyX1sqFeOUCbV/EPN+ZEcHROClAMEyINgRZFBGXbe5IH9f S03kvOhYh3moKlUpOJiCSIXqFJ3ubm0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-438-WfDJ3MOTPVeX0K0c1Yjy4Q-1; Thu, 14 Jan 2021 23:46:55 -0500 X-MC-Unique: WfDJ3MOTPVeX0K0c1Yjy4Q-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A6E30802B45; Fri, 15 Jan 2021 04:46:51 +0000 (UTC) Received: from [10.72.13.19] (ovpn-13-19.pek2.redhat.com [10.72.13.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id A958771D52; Fri, 15 Jan 2021 04:46:29 +0000 (UTC) Subject: Re: [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU To: Lu Baolu , tglx@linutronix.de, ashok.raj@intel.com, kevin.tian@intel.com, dave.jiang@intel.com, megha.dey@intel.com, dwmw2@infradead.org Cc: alex.williamson@redhat.com, bhelgaas@google.com, dan.j.williams@intel.com, will@kernel.org, joro@8bytes.org, dmaengine@vger.kernel.org, eric.auger@redhat.com, jacob.jun.pan@intel.com, jgg@mellanox.com, kvm@vger.kernel.org, kwankhede@nvidia.com, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, iommu@lists.linux-foundation.org, maz@kernel.org, mona.hossain@intel.com, netanelg@mellanox.com, parav@mellanox.com, pbonzini@redhat.com, rafael@kernel.org, samuel.ortiz@intel.com, sanjay.k.kumar@intel.com, shahafs@mellanox.com, tony.luck@intel.com, vkoul@kernel.org, yan.y.zhao@linux.intel.com, yi.l.liu@intel.com, leon@kernel.org References: <20210114013003.297050-1-baolu.lu@linux.intel.com> <20210114013003.297050-2-baolu.lu@linux.intel.com> From: Jason Wang Message-ID: Date: Fri, 15 Jan 2021 12:46:28 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210114013003.297050-2-baolu.lu@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 2021/1/14 上午9:30, Lu Baolu wrote: > Some vendor IOMMU drivers are able to declare that it is running in a VM > context. This is very valuable for the features that only want to be > supported on bare metal. Add a capability bit so that it could be used. > > Signed-off-by: Lu Baolu > --- > drivers/iommu/intel/iommu.c | 20 ++++++++++++++++++++ > drivers/iommu/virtio-iommu.c | 9 +++++++++ > include/linux/iommu.h | 1 + > 3 files changed, 30 insertions(+) > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c > index cb205a04fe4c..8eb022d0e8aa 100644 > --- a/drivers/iommu/intel/iommu.c > +++ b/drivers/iommu/intel/iommu.c > @@ -5738,12 +5738,32 @@ static inline bool nested_mode_support(void) > return ret; > } > > +static inline bool caching_mode_enabled(void) > +{ > + struct dmar_drhd_unit *drhd; > + struct intel_iommu *iommu; > + bool ret = false; > + > + rcu_read_lock(); > + for_each_active_iommu(iommu, drhd) { > + if (cap_caching_mode(iommu->cap)) { > + ret = true; > + break; > + } > + } > + rcu_read_unlock(); > + > + return ret; > +} > + > static bool intel_iommu_capable(enum iommu_cap cap) > { > if (cap == IOMMU_CAP_CACHE_COHERENCY) > return domain_update_iommu_snooping(NULL) == 1; > if (cap == IOMMU_CAP_INTR_REMAP) > return irq_remapping_enabled == 1; > + if (cap == IOMMU_CAP_VIOMMU) > + return caching_mode_enabled(); This part I don't understand. Does it mean Intel IOMMU can't be used in VM without caching mode? Thanks > > return false; > } > diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c > index 2bfdd5734844..719793e103db 100644 > --- a/drivers/iommu/virtio-iommu.c > +++ b/drivers/iommu/virtio-iommu.c > @@ -931,7 +931,16 @@ static int viommu_of_xlate(struct device *dev, struct of_phandle_args *args) > return iommu_fwspec_add_ids(dev, args->args, 1); > } > > +static bool viommu_capable(enum iommu_cap cap) > +{ > + if (cap == IOMMU_CAP_VIOMMU) > + return true; > + > + return false; > +} > + > static struct iommu_ops viommu_ops = { > + .capable = viommu_capable, > .domain_alloc = viommu_domain_alloc, > .domain_free = viommu_domain_free, > .attach_dev = viommu_attach_dev, > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index b95a6f8db6ff..1d24be667a03 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -94,6 +94,7 @@ enum iommu_cap { > transactions */ > IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */ > IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */ > + IOMMU_CAP_VIOMMU, /* IOMMU can declar running in a VM */ > }; > > /*