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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 37CC4C433E1 for ; Mon, 6 Jul 2020 10:37:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 093BE20772 for ; Mon, 6 Jul 2020 10:37:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="V4iYw2i4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728943AbgGFKhc (ORCPT ); Mon, 6 Jul 2020 06:37:32 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:27023 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728422AbgGFKhb (ORCPT ); Mon, 6 Jul 2020 06:37:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594031849; 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=A2TH0l40UUZw3trZBCC+/hrIk4R1Tqn0kicJMiXyx/I=; b=V4iYw2i4v6UpnNcv05AGXiEapWXtOUnqKxFIwqOw2ZJ/Z9PC8xAGeXP5Fqs2mBGtJBXeQo ovwmD44CyPgoEHvf2N0FI8LS0sfrJXI7TyAQ6VKD2HuJC2edn7jAI+tS5+cu8AGsWwwaF8 HXIVLiQlaPvd9/5FJ/VF6/DGCDzpC+I= 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-79-n2jXDVxFO3Od9r5VdJEaVQ-1; Mon, 06 Jul 2020 06:37:25 -0400 X-MC-Unique: n2jXDVxFO3Od9r5VdJEaVQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1BA66EC1A0; Mon, 6 Jul 2020 10:37:23 +0000 (UTC) Received: from [10.36.113.241] (ovpn-113-241.ams2.redhat.com [10.36.113.241]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D380D10013C2; Mon, 6 Jul 2020 10:37:13 +0000 (UTC) Subject: Re: [PATCH v4 04/15] vfio/type1: Report iommu nesting info to userspace To: Liu Yi L , alex.williamson@redhat.com, baolu.lu@linux.intel.com, joro@8bytes.org Cc: kevin.tian@intel.com, jacob.jun.pan@linux.intel.com, ashok.raj@intel.com, jun.j.tian@intel.com, yi.y.sun@intel.com, jean-philippe@linaro.org, peterx@redhat.com, hao.wu@intel.com, stefanha@gmail.com, iommu@lists.linux-foundation.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org References: <1593861989-35920-1-git-send-email-yi.l.liu@intel.com> <1593861989-35920-5-git-send-email-yi.l.liu@intel.com> From: Auger Eric Message-ID: Date: Mon, 6 Jul 2020 12:37:12 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <1593861989-35920-5-git-send-email-yi.l.liu@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Yi, On 7/4/20 1:26 PM, Liu Yi L wrote: > This patch exports iommu nesting capability info to user space through > VFIO. User space is expected to check this info for supported uAPIs (e.g. > PASID alloc/free, bind page table, and cache invalidation) and the vendor > specific format information for first level/stage page table that will be > bound to. > > The nesting info is available only after the nesting iommu type is set > for a container. Current implementation imposes one limitation - one > nesting container should include at most one group. The philosophy of > vfio container is having all groups/devices within the container share > the same IOMMU context. When vSVA is enabled, one IOMMU context could > include one 2nd-level address space and multiple 1st-level address spaces. > While the 2nd-leve address space is reasonably sharable by multiple groups level > , blindly sharing 1st-level address spaces across all groups within the > container might instead break the guest expectation. In the future sub/ > super container concept might be introduced to allow partial address space > sharing within an IOMMU context. But for now let's go with this restriction > by requiring singleton container for using nesting iommu features. Below > link has the related discussion about this decision. > > https://lkml.org/lkml/2020/5/15/1028 > > Cc: Kevin Tian > CC: Jacob Pan > Cc: Alex Williamson > Cc: Eric Auger > Cc: Jean-Philippe Brucker > Cc: Joerg Roedel > Cc: Lu Baolu > Signed-off-by: Liu Yi L > --- > v3 -> v4: > *) address comments against v3. > > v1 -> v2: > *) added in v2 > --- > > drivers/vfio/vfio_iommu_type1.c | 105 +++++++++++++++++++++++++++++++++++----- > include/uapi/linux/vfio.h | 16 ++++++ > 2 files changed, 109 insertions(+), 12 deletions(-) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index 7accb59..80623b8 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -62,18 +62,20 @@ MODULE_PARM_DESC(dma_entry_limit, > "Maximum number of user DMA mappings per container (65535)."); > > struct vfio_iommu { > - struct list_head domain_list; > - struct list_head iova_list; > - struct vfio_domain *external_domain; /* domain for external user */ > - struct mutex lock; > - struct rb_root dma_list; > - struct blocking_notifier_head notifier; > - unsigned int dma_avail; > - uint64_t pgsize_bitmap; > - bool v2; > - bool nesting; > - bool dirty_page_tracking; > - bool pinned_page_dirty_scope; > + struct list_head domain_list; > + struct list_head iova_list; > + struct vfio_domain *external_domain; /* domain for > + external user */ nit: put the comment before the field? > + struct mutex lock; > + struct rb_root dma_list; > + struct blocking_notifier_head notifier; > + unsigned int dma_avail; > + uint64_t pgsize_bitmap; > + bool v2; > + bool nesting; > + bool dirty_page_tracking; > + bool pinned_page_dirty_scope; > + struct iommu_nesting_info *nesting_info; > }; > > struct vfio_domain { > @@ -130,6 +132,9 @@ struct vfio_regions { > #define IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) \ > (!list_empty(&iommu->domain_list)) > > +#define IS_DOMAIN_IN_CONTAINER(iommu) ((iommu->external_domain) || \ > + (!list_empty(&iommu->domain_list))) rename into something like CONTAINER_HAS_DOMAIN()? > + > #define DIRTY_BITMAP_BYTES(n) (ALIGN(n, BITS_PER_TYPE(u64)) / BITS_PER_BYTE) > > /* > @@ -1929,6 +1934,13 @@ static void vfio_iommu_iova_insert_copy(struct vfio_iommu *iommu, > > list_splice_tail(iova_copy, iova); > } > + > +static void vfio_iommu_release_nesting_info(struct vfio_iommu *iommu) > +{ > + kfree(iommu->nesting_info); > + iommu->nesting_info = NULL; > +} > + > static int vfio_iommu_type1_attach_group(void *iommu_data, > struct iommu_group *iommu_group) > { > @@ -1959,6 +1971,12 @@ static int vfio_iommu_type1_attach_group(void *iommu_data, > } > } > > + /* Nesting type container can include only one group */ > + if (iommu->nesting && IS_DOMAIN_IN_CONTAINER(iommu)) { > + mutex_unlock(&iommu->lock); > + return -EINVAL; > + } > + > group = kzalloc(sizeof(*group), GFP_KERNEL); > domain = kzalloc(sizeof(*domain), GFP_KERNEL); > if (!group || !domain) { > @@ -2029,6 +2047,36 @@ static int vfio_iommu_type1_attach_group(void *iommu_data, > if (ret) > goto out_domain; > > + /* Nesting cap info is available only after attaching */ > + if (iommu->nesting) { > + struct iommu_nesting_info tmp; > + struct iommu_nesting_info *info; > + > + /* First get the size of vendor specific nesting info */ > + ret = iommu_domain_get_attr(domain->domain, > + DOMAIN_ATTR_NESTING, > + &tmp); > + if (ret) > + goto out_detach; > + > + info = kzalloc(tmp.size, GFP_KERNEL); nit: you may directly use iommu->nesting_info > + if (!info) { > + ret = -ENOMEM; > + goto out_detach; > + } > + > + /* Now get the nesting info */ > + info->size = tmp.size; > + ret = iommu_domain_get_attr(domain->domain, > + DOMAIN_ATTR_NESTING, > + info); > + if (ret) { > + kfree(info); ... and set it back to NULL here if it fails > + goto out_detach; > + } > + iommu->nesting_info = info; > + } > + > /* Get aperture info */ > iommu_domain_get_attr(domain->domain, DOMAIN_ATTR_GEOMETRY, &geo); > > @@ -2138,6 +2186,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data, > return 0; > > out_detach: > + vfio_iommu_release_nesting_info(iommu); > vfio_iommu_detach_group(domain, group); > out_domain: > iommu_domain_free(domain->domain); > @@ -2338,6 +2387,8 @@ static void vfio_iommu_type1_detach_group(void *iommu_data, > vfio_iommu_unmap_unpin_all(iommu); > else > vfio_iommu_unmap_unpin_reaccount(iommu); > + > + vfio_iommu_release_nesting_info(iommu); > } > iommu_domain_free(domain->domain); > list_del(&domain->next); > @@ -2546,6 +2597,30 @@ static int vfio_iommu_migration_build_caps(struct vfio_iommu *iommu, > return vfio_info_add_capability(caps, &cap_mig.header, sizeof(cap_mig)); > } > > +static int vfio_iommu_info_add_nesting_cap(struct vfio_iommu *iommu, > + struct vfio_info_cap *caps) > +{ > + struct vfio_info_cap_header *header; > + struct vfio_iommu_type1_info_cap_nesting *nesting_cap; > + size_t size; > + > + size = sizeof(*nesting_cap) + iommu->nesting_info->size; > + > + header = vfio_info_cap_add(caps, size, > + VFIO_IOMMU_TYPE1_INFO_CAP_NESTING, 1); > + if (IS_ERR(header)) > + return PTR_ERR(header); > + > + nesting_cap = container_of(header, > + struct vfio_iommu_type1_info_cap_nesting, > + header); > + > + memcpy(&nesting_cap->info, iommu->nesting_info, > + iommu->nesting_info->size); > + > + return 0; > +} > + > static int vfio_iommu_type1_get_info(struct vfio_iommu *iommu, > unsigned long arg) > { > @@ -2586,6 +2661,12 @@ static int vfio_iommu_type1_get_info(struct vfio_iommu *iommu, > if (ret) > return ret; > > + if (iommu->nesting_info) { > + ret = vfio_iommu_info_add_nesting_cap(iommu, &caps); > + if (ret) > + return ret; > + } > + > if (caps.size) { > info.flags |= VFIO_IOMMU_INFO_CAPS; > > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > index 9204705..3e3de9c 100644 > --- a/include/uapi/linux/vfio.h > +++ b/include/uapi/linux/vfio.h > @@ -1039,6 +1039,22 @@ struct vfio_iommu_type1_info_cap_migration { > __u64 max_dirty_bitmap_size; /* in bytes */ > }; > > +#define VFIO_IOMMU_TYPE1_INFO_CAP_NESTING 3 You may improve the documentation by taking examples from the above caps. > + > +/* > + * Reporting nesting info to user space. > + * > + * @info: the nesting info provided by IOMMU driver. Today > + * it is expected to be a struct iommu_nesting_info > + * data. Is it expected to change? > + */ > +struct vfio_iommu_type1_info_cap_nesting { > + struct vfio_info_cap_header header; > + __u32 flags; You may document flags. > + __u32 padding; > + __u8 info[]; > +}; > + > #define VFIO_IOMMU_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12) > > /** > Thanks Eric