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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 029ECC3276C for ; Fri, 3 Jan 2020 01:11:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CDD6C2085B for ; Fri, 3 Jan 2020 01:11:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726299AbgACBLE (ORCPT ); Thu, 2 Jan 2020 20:11:04 -0500 Received: from mga02.intel.com ([134.134.136.20]:59866 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725872AbgACBLD (ORCPT ); Thu, 2 Jan 2020 20:11:03 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Jan 2020 17:11:02 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,388,1571727600"; d="scan'208";a="221511337" Received: from joy-optiplex-7040.sh.intel.com ([10.239.13.9]) by orsmga006.jf.intel.com with ESMTP; 02 Jan 2020 17:11:01 -0800 From: Yan Zhao To: alex.williamson@redhat.com Cc: zhenyuw@linux.intel.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, intel-gvt@eclists.intel.com, pbonzini@redhat.com, kevin.tian@intel.com, Yan Zhao Subject: [PATCH 1/2] vfio: introduce vfio_iova_rw to read/write a range of IOVAs Date: Thu, 2 Jan 2020 20:02:17 -0500 Message-Id: <20200103010217.4201-1-yan.y.zhao@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200103010055.4140-1-yan.y.zhao@intel.com> References: <20200103010055.4140-1-yan.y.zhao@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org vfio_iova_rw will read/write a range of userspace memory (starting form device iova to iova + len -1) into a kenrel buffer without pinning the userspace memory. TODO: vfio needs to mark the iova dirty if vfio_iova_rw(write) is called. Cc: Kevin Tian Signed-off-by: Yan Zhao --- drivers/vfio/vfio.c | 45 ++++++++++++++++++ drivers/vfio/vfio_iommu_type1.c | 81 +++++++++++++++++++++++++++++++++ include/linux/vfio.h | 5 ++ 3 files changed, 131 insertions(+) diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index c8482624ca34..36e91e647ed5 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -1961,6 +1961,51 @@ int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn, int npage) } EXPORT_SYMBOL(vfio_unpin_pages); +/* + * Read/Write a range of userspace IOVAs for a device into/from a kernel + * buffer without pinning the userspace memory + * @dev [in] : device + * @iova [in] : base IOVA of a userspace buffer + * @data [in] : pointer to kernel buffer + * @len [in] : kernel buffer length + * @write : indicate read or write + * Return error on failure or 0 on success. + */ +int vfio_iova_rw(struct device *dev, unsigned long iova, void *data, + unsigned long len, bool write) +{ + struct vfio_container *container; + struct vfio_group *group; + struct vfio_iommu_driver *driver; + int ret = 0; + + if (!dev || !data || len <= 0) + return -EINVAL; + + group = vfio_group_get_from_dev(dev); + if (!group) + return -ENODEV; + + ret = vfio_group_add_container_user(group); + if (ret) + goto out; + + container = group->container; + driver = container->iommu_driver; + + if (likely(driver && driver->ops->iova_rw)) + ret = driver->ops->iova_rw(container->iommu_data, + iova, data, len, write); + else + ret = -ENOTTY; + + vfio_group_try_dissolve_container(group); +out: + vfio_group_put(group); + return ret; +} +EXPORT_SYMBOL(vfio_iova_rw); + static int vfio_register_iommu_notifier(struct vfio_group *group, unsigned long *events, struct notifier_block *nb) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 2ada8e6cdb88..aee191077235 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -2326,6 +2327,85 @@ static int vfio_iommu_type1_unregister_notifier(void *iommu_data, return blocking_notifier_chain_unregister(&iommu->notifier, nb); } +static int next_segment(unsigned long len, int offset) +{ + if (len > PAGE_SIZE - offset) + return PAGE_SIZE - offset; + else + return len; +} + +static int vfio_iommu_type1_rw_iova_seg(struct vfio_iommu *iommu, + unsigned long iova, void *data, + unsigned long seg_len, + unsigned long offset, + bool write) +{ + struct mm_struct *mm; + unsigned long vaddr; + struct vfio_dma *dma; + bool kthread = current->mm == NULL; + int ret = 0; + + dma = vfio_find_dma(iommu, iova, PAGE_SIZE); + if (!dma) + return -EINVAL; + + mm = get_task_mm(dma->task); + + if (!mm) + return -ENODEV; + + if (kthread) + use_mm(mm); + else if (current->mm != mm) { + ret = -EINVAL; + goto out; + } + + vaddr = dma->vaddr + iova - dma->iova + offset; + + ret = write ? __copy_to_user((void __user *)vaddr, + data, seg_len) : + __copy_from_user(data, (void __user *)vaddr, + seg_len); + if (ret) + ret = -EFAULT; + + if (kthread) + unuse_mm(mm); +out: + mmput(mm); + return ret; +} + +static int vfio_iommu_type1_iova_rw(void *iommu_data, unsigned long iova, + void *data, unsigned long len, bool write) +{ + struct vfio_iommu *iommu = iommu_data; + int offset = iova & ~PAGE_MASK; + int seg_len; + int ret = 0; + + iova = iova & PAGE_MASK; + + mutex_lock(&iommu->lock); + while ((seg_len = next_segment(len, offset)) > 0) { + ret = vfio_iommu_type1_rw_iova_seg(iommu, iova, data, + seg_len, offset, write); + if (ret) + break; + + offset = 0; + len -= seg_len; + data += seg_len; + iova += PAGE_SIZE; + } + + mutex_unlock(&iommu->lock); + return ret; +} + static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = { .name = "vfio-iommu-type1", .owner = THIS_MODULE, @@ -2338,6 +2418,7 @@ static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = { .unpin_pages = vfio_iommu_type1_unpin_pages, .register_notifier = vfio_iommu_type1_register_notifier, .unregister_notifier = vfio_iommu_type1_unregister_notifier, + .iova_rw = vfio_iommu_type1_iova_rw, }; static int __init vfio_iommu_type1_init(void) diff --git a/include/linux/vfio.h b/include/linux/vfio.h index e42a711a2800..7bf18a31bbcf 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -82,6 +82,8 @@ struct vfio_iommu_driver_ops { struct notifier_block *nb); int (*unregister_notifier)(void *iommu_data, struct notifier_block *nb); + int (*iova_rw)(void *iommu_data, unsigned long iova, + void *data, unsigned long len, bool write); }; extern int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops); @@ -107,6 +109,9 @@ extern int vfio_pin_pages(struct device *dev, unsigned long *user_pfn, extern int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn, int npage); +extern int vfio_iova_rw(struct device *dev, unsigned long iova, void *data, + unsigned long len, bool write); + /* each type has independent events */ enum vfio_notify_type { VFIO_IOMMU_NOTIFY = 0, -- 2.17.1