From patchwork Mon Mar 27 09:40:44 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Liu X-Patchwork-Id: 13188944 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 20365C7619A for ; Mon, 27 Mar 2023 09:41:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233103AbjC0Jlg (ORCPT ); Mon, 27 Mar 2023 05:41:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34612 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232910AbjC0JlN (ORCPT ); Mon, 27 Mar 2023 05:41:13 -0400 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4688D4EE4; Mon, 27 Mar 2023 02:41:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1679910069; x=1711446069; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Y/RFhwQ5W6F9CvyAdkMONK+H5oqSicTbyLKo0teaNp4=; b=HXDHFR3ESqAoBdU2A3IMkjrcp7F4KK07XOwuUqmcOY/Byg6raWEWVtOT IKP/SwBpTUVeS76mm6y6RZcZZj0s06l9sfxAwCoOA0NRqPEN0DJgagg4L cHsB5vTchgUWA7X/VxO9pU2qYvmekd8USFAV7ic9Dh7po4HDRPiA0lB/i H55rhXEQWEEIdRiMiqcoXpHS7alYbJQ3bQ8B0E5XOmLixTSI+Eh5aBhpD ZZlo2hiZZxvwZsqSExQ/j4tlXfN58BY/Y+xF7z3O3ZRRkV2nWPx58c+Rw K9Vx7aawUZaXhb8w+gWnTx06BiR5AaBNka97ZxIVRNcI6DKobOXHT1k1I w==; X-IronPort-AV: E=McAfee;i="6600,9927,10661"; a="426485466" X-IronPort-AV: E=Sophos;i="5.98,294,1673942400"; d="scan'208";a="426485466" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Mar 2023 02:41:07 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10661"; a="660775856" X-IronPort-AV: E=Sophos;i="5.98,294,1673942400"; d="scan'208";a="660775856" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by orsmga006.jf.intel.com with ESMTP; 27 Mar 2023 02:41:07 -0700 From: Yi Liu To: alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com Cc: joro@8bytes.org, robin.murphy@arm.com, cohuck@redhat.com, eric.auger@redhat.com, nicolinc@nvidia.com, kvm@vger.kernel.org, mjrosato@linux.ibm.com, chao.p.peng@linux.intel.com, yi.l.liu@intel.com, yi.y.sun@linux.intel.com, peterx@redhat.com, jasowang@redhat.com, shameerali.kolothum.thodi@huawei.com, lulu@redhat.com, suravee.suthikulpanit@amd.com, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-s390@vger.kernel.org, xudong.hao@intel.com, yan.y.zhao@intel.com, terrence.xu@intel.com, yanting.jiang@intel.com Subject: [PATCH v8 21/24] vfio: Add VFIO_DEVICE_BIND_IOMMUFD Date: Mon, 27 Mar 2023 02:40:44 -0700 Message-Id: <20230327094047.47215-22-yi.l.liu@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230327094047.47215-1-yi.l.liu@intel.com> References: <20230327094047.47215-1-yi.l.liu@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org This adds ioctl for userspace to bind device cdev fd to iommufd. VFIO_DEVICE_BIND_IOMMUFD: bind device to an iommufd, hence gain DMA control provided by the iommufd. open_device op is called after bind_iommufd op. VFIO no iommu mode is indicated by passing a negative iommufd value. Reviewed-by: Kevin Tian Tested-by: Terrence Xu Signed-off-by: Yi Liu --- drivers/vfio/device_cdev.c | 153 +++++++++++++++++++++++++++++++++++++ drivers/vfio/vfio.h | 13 ++++ drivers/vfio/vfio_main.c | 5 ++ include/uapi/linux/vfio.h | 37 +++++++++ 4 files changed, 208 insertions(+) diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c index 1c640016a824..2b563bac50b9 100644 --- a/drivers/vfio/device_cdev.c +++ b/drivers/vfio/device_cdev.c @@ -3,6 +3,7 @@ * Copyright (c) 2023 Intel Corporation. */ #include +#include #include "vfio.h" @@ -44,6 +45,158 @@ int vfio_device_fops_cdev_open(struct inode *inode, struct file *filep) return ret; } +static void vfio_device_get_kvm_safe(struct vfio_device_file *df) +{ + spin_lock(&df->kvm_ref_lock); + if (df->kvm) + _vfio_device_get_kvm_safe(df->device, df->kvm); + spin_unlock(&df->kvm_ref_lock); +} + +void vfio_device_cdev_close(struct vfio_device_file *df) +{ + struct vfio_device *device = df->device; + + /* + * As df->access_granted writer is under dev_set->lock as well, + * so this read no need to use smp_load_acquire() to pair with + * smp_store_release() in the caller of vfio_device_open(). + */ + if (!df->access_granted) + return; + + mutex_lock(&device->dev_set->lock); + vfio_device_close(df); + vfio_device_put_kvm(device); + if (df->iommufd) + iommufd_ctx_put(df->iommufd); + mutex_unlock(&device->dev_set->lock); + vfio_device_unblock_group(device); +} + +static int vfio_device_cdev_enable_noiommu(struct vfio_device *device) +{ + if (!capable(CAP_SYS_RAWIO)) + return -EPERM; + + if (!device->noiommu) + return -EINVAL; + + return 0; +} + +static struct iommufd_ctx *vfio_get_iommufd_from_fd(int fd) +{ + struct fd f; + struct iommufd_ctx *iommufd; + + f = fdget(fd); + if (!f.file) + return ERR_PTR(-EBADF); + + iommufd = iommufd_ctx_from_file(f.file); + + fdput(f); + return iommufd; +} + +long vfio_device_ioctl_bind_iommufd(struct vfio_device_file *df, + struct vfio_device_bind_iommufd __user *arg) +{ + struct vfio_device *device = df->device; + struct vfio_device_bind_iommufd bind; + struct iommufd_ctx *iommufd = NULL; + unsigned long minsz; + int ret; + + static_assert(__same_type(arg->out_devid, bind.out_devid)); + + minsz = offsetofend(struct vfio_device_bind_iommufd, out_devid); + + if (copy_from_user(&bind, arg, minsz)) + return -EFAULT; + + if (bind.argsz < minsz || bind.flags) + return -EINVAL; + + if (!device->ops->bind_iommufd) + return -ENODEV; + + /* BIND_IOMMUFD only allowed for cdev fds */ + if (df->group) + return -EINVAL; + + ret = vfio_device_block_group(device); + if (ret) + return ret; + + mutex_lock(&device->dev_set->lock); + /* one device cannot be bound twice */ + if (df->access_granted) { + ret = -EINVAL; + goto out_unlock; + } + + /* iommufd < 0 means noiommu mode */ + if (bind.iommufd < 0) { + ret = vfio_device_cdev_enable_noiommu(device); + if (ret) + goto out_unlock; + } else { + iommufd = vfio_get_iommufd_from_fd(bind.iommufd); + if (IS_ERR(iommufd)) { + ret = PTR_ERR(iommufd); + goto out_unlock; + } + } + + /* + * Before the device open, get the KVM pointer currently + * associated with the device file (if there is) and obtain + * a reference. This reference is held until device closed. + * Save the pointer in the device for use by drivers. + */ + vfio_device_get_kvm_safe(df); + + df->iommufd = iommufd; + ret = vfio_device_open(df); + if (ret) + goto out_put_kvm; + + if (df->iommufd) + bind.out_devid = df->devid; + + ret = copy_to_user(&arg->out_devid, &bind.out_devid, + sizeof(bind.out_devid)) ? -EFAULT : 0; + if (ret) + goto out_close_device; + + if (bind.iommufd < 0) + dev_warn(device->dev, "device is bound to vfio-noiommu by user " + "(%s:%d)\n", current->comm, task_pid_nr(current)); + + /* + * Paired with smp_load_acquire() in vfio_device_fops::ioctl/ + * read/write/mmap + */ + smp_store_release(&df->access_granted, true); + mutex_unlock(&device->dev_set->lock); + + return 0; + +out_close_device: + vfio_device_close(df); +out_put_kvm: + df->iommufd = NULL; + vfio_device_put_kvm(device); + if (iommufd) + iommufd_ctx_put(iommufd); +out_unlock: + mutex_unlock(&device->dev_set->lock); + vfio_device_unblock_group(device); + return ret; +} + static char *vfio_device_devnode(const struct device *dev, umode_t *mode) { return kasprintf(GFP_KERNEL, "vfio/devices/%s", dev_name(dev)); diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h index 3a8fd0e32f59..ace3d52b0928 100644 --- a/drivers/vfio/vfio.h +++ b/drivers/vfio/vfio.h @@ -281,6 +281,9 @@ static inline void vfio_device_del(struct vfio_device *device) void vfio_init_device_cdev(struct vfio_device *device); int vfio_device_fops_cdev_open(struct inode *inode, struct file *filep); +void vfio_device_cdev_close(struct vfio_device_file *df); +long vfio_device_ioctl_bind_iommufd(struct vfio_device_file *df, + struct vfio_device_bind_iommufd __user *arg); int vfio_cdev_init(struct class *device_class); void vfio_cdev_cleanup(void); #else @@ -304,6 +307,16 @@ static inline int vfio_device_fops_cdev_open(struct inode *inode, return 0; } +static inline void vfio_device_cdev_close(struct vfio_device_file *df) +{ +} + +static inline long vfio_device_ioctl_bind_iommufd(struct vfio_device_file *df, + struct vfio_device_bind_iommufd __user *arg) +{ + return -EOPNOTSUPP; +} + static inline int vfio_cdev_init(struct class *device_class) { return 0; diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index 58fc3bb768f2..375086c8803f 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -559,6 +559,8 @@ static int vfio_device_fops_release(struct inode *inode, struct file *filep) if (df->group) vfio_device_group_close(df); + else + vfio_device_cdev_close(df); vfio_device_put_registration(device); @@ -1132,6 +1134,9 @@ static long vfio_device_fops_unl_ioctl(struct file *filep, struct vfio_device *device = df->device; int ret; + if (cmd == VFIO_DEVICE_BIND_IOMMUFD) + return vfio_device_ioctl_bind_iommufd(df, (void __user *)arg); + /* Paired with smp_store_release() following vfio_device_open() */ if (!smp_load_acquire(&df->access_granted)) return -EINVAL; diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 61b801dfd40b..62b2f2497525 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -194,6 +194,43 @@ struct vfio_group_status { /* --------------- IOCTLs for DEVICE file descriptors --------------- */ +/* + * VFIO_DEVICE_BIND_IOMMUFD - _IOR(VFIO_TYPE, VFIO_BASE + 19, + * struct vfio_device_bind_iommufd) + * + * Bind a vfio_device to the specified iommufd. + * + * The user should provide a device cookie when calling this ioctl. The + * cookie is carried only in event e.g. I/O fault reported to userspace + * via iommufd. The user should use devid returned by this ioctl to mark + * the target device in other ioctls (e.g. iommu hardware infomration query + * via iommufd, and etc.). + * + * User is not allowed to access the device before the binding operation + * is completed. + * + * Unbind is automatically conducted when device fd is closed. + * + * @argsz: user filled size of this data. + * @flags: reserved for future extension. + * @dev_cookie: a per device cookie provided by userspace. + * @iommufd: iommufd to bind. a negative value means noiommu. + * @out_devid: the device id generated by this bind. This field is valid + * as long as the input @iommufd is valid. Otherwise, it is + * meaningless. + * + * Return: 0 on success, -errno on failure. + */ +struct vfio_device_bind_iommufd { + __u32 argsz; + __u32 flags; + __aligned_u64 dev_cookie; + __s32 iommufd; + __u32 out_devid; +}; + +#define VFIO_DEVICE_BIND_IOMMUFD _IO(VFIO_TYPE, VFIO_BASE + 19) + /** * VFIO_DEVICE_GET_INFO - _IOR(VFIO_TYPE, VFIO_BASE + 7, * struct vfio_device_info)