From patchwork Thu Aug 5 17:07:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 12421687 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=-16.4 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,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 0B904C432BE for ; Thu, 5 Aug 2021 17:07:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD5556113B for ; Thu, 5 Aug 2021 17:07:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237105AbhHERHh (ORCPT ); Thu, 5 Aug 2021 13:07:37 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:30438 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236937AbhHERHf (ORCPT ); Thu, 5 Aug 2021 13:07:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628183239; 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=flm8HIEA9Hn4PQkZkDKodDdN26bAb3fK34DI1Ef+s1Y=; b=JxGySDyXy7NRqauDdkvZdtyq/Nnba1G61d3b5DJ3brrlrgSSMCJttYywAyOpASUtWIH2W4 oUxqIVFyU9l/+t6ZVO1mT3xIo7DsgRp/V+MjbAFjSH/ZxCkHR+3oqnjsofBUUaKrGfPJn8 1QhP2kBZA831z8bFTi1m2pOmlm9NK5I= 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-218-QtE1bS47OD62_5TOMO9ZJQ-1; Thu, 05 Aug 2021 13:07:18 -0400 X-MC-Unique: QtE1bS47OD62_5TOMO9ZJQ-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 2C9B3190A7A0; Thu, 5 Aug 2021 17:07:17 +0000 (UTC) Received: from [172.30.41.16] (ovpn-113-77.phx2.redhat.com [10.3.113.77]) by smtp.corp.redhat.com (Postfix) with ESMTP id A7DD71000186; Thu, 5 Aug 2021 17:07:09 +0000 (UTC) Subject: [PATCH 1/7] vfio: Create vfio_fs_type with inode per device From: Alex Williamson To: alex.williamson@redhat.com Cc: Jason Gunthorpe , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, jgg@nvidia.com, peterx@redhat.com Date: Thu, 05 Aug 2021 11:07:09 -0600 Message-ID: <162818322947.1511194.6035266132085405252.stgit@omen> In-Reply-To: <162818167535.1511194.6614962507750594786.stgit@omen> References: <162818167535.1511194.6614962507750594786.stgit@omen> User-Agent: StGit/1.0-8-g6af9-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org By linking all the device fds we provide to userspace to an address space through a new pseudo fs, we can use tools like unmap_mapping_range() to zap all vmas associated with a device. Suggested-by: Jason Gunthorpe Signed-off-by: Alex Williamson --- drivers/vfio/vfio.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/vfio.h | 1 + 2 files changed, 58 insertions(+) diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 02cc51ce6891..b88de89bda31 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -21,8 +21,10 @@ #include #include #include +#include #include #include +#include #include #include #include @@ -37,6 +39,14 @@ #define DRIVER_AUTHOR "Alex Williamson " #define DRIVER_DESC "VFIO - User Level meta-driver" +/* + * Not exposed via UAPI + * + * XXX Adopt the following when available: + * https://lore.kernel.org/lkml/20210309155348.974875-1-hch@lst.de/ + */ +#define VFIO_MAGIC 0x5646494f /* "VFIO" */ + static struct vfio { struct class *class; struct list_head iommu_drivers_list; @@ -46,6 +56,8 @@ static struct vfio { struct mutex group_lock; struct cdev group_cdev; dev_t group_devt; + struct vfsmount *vfio_fs_mnt; + int vfio_fs_cnt; } vfio; struct vfio_iommu_driver { @@ -519,6 +531,35 @@ static struct vfio_group *vfio_group_get_from_dev(struct device *dev) return group; } +static int vfio_fs_init_fs_context(struct fs_context *fc) +{ + return init_pseudo(fc, VFIO_MAGIC) ? 0 : -ENOMEM; +} + +static struct file_system_type vfio_fs_type = { + .name = "vfio", + .owner = THIS_MODULE, + .init_fs_context = vfio_fs_init_fs_context, + .kill_sb = kill_anon_super, +}; + +static struct inode *vfio_fs_inode_new(void) +{ + struct inode *inode; + int ret; + + ret = simple_pin_fs(&vfio_fs_type, + &vfio.vfio_fs_mnt, &vfio.vfio_fs_cnt); + if (ret) + return ERR_PTR(ret); + + inode = alloc_anon_inode(vfio.vfio_fs_mnt->mnt_sb); + if (IS_ERR(inode)) + simple_release_fs(&vfio.vfio_fs_mnt, &vfio.vfio_fs_cnt); + + return inode; +} + /** * Device objects - create, release, get, put, search */ @@ -783,6 +824,12 @@ int vfio_register_group_dev(struct vfio_device *device) return -EBUSY; } + device->inode = vfio_fs_inode_new(); + if (IS_ERR(device->inode)) { + vfio_group_put(group); + return PTR_ERR(device->inode); + } + /* Our reference on group is moved to the device */ device->group = group; @@ -907,6 +954,9 @@ void vfio_unregister_group_dev(struct vfio_device *device) group->dev_counter--; mutex_unlock(&group->device_lock); + iput(device->inode); + simple_release_fs(&vfio.vfio_fs_mnt, &vfio.vfio_fs_cnt); + /* * In order to support multiple devices per group, devices can be * plucked from the group while other devices in the group are still @@ -1411,6 +1461,13 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) */ filep->f_mode |= (FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); + /* + * Use the pseudo fs inode on the device to link all mmaps + * to the same address space, allowing us to unmap all vmas + * associated to this device using unmap_mapping_range(). + */ + filep->f_mapping = device->inode->i_mapping; + atomic_inc(&group->container_users); fd_install(ret, filep); diff --git a/include/linux/vfio.h b/include/linux/vfio.h index a2c5b30e1763..90bcc2e9c8eb 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -24,6 +24,7 @@ struct vfio_device { refcount_t refcount; struct completion comp; struct list_head group_next; + struct inode *inode; }; /**