From patchwork Tue Aug 8 15:35:09 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Liu X-Patchwork-Id: 13346454 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 DB207C001B0 for ; Tue, 8 Aug 2023 17:04:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232571AbjHHRET (ORCPT ); Tue, 8 Aug 2023 13:04:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51242 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232608AbjHHRDi (ORCPT ); Tue, 8 Aug 2023 13:03:38 -0400 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 40E5119BCB; Tue, 8 Aug 2023 09:01:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1691510498; x=1723046498; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=GyCmoX+U+5WHaDilGZwEdrDS06FXJn+Wlm/dN8j6Mtg=; b=PtyCVupv4Ye6tE9iNaZsqJCMtK0So2DcEXrhNRgheGb3kcHqr7VflCmb yCD4Zzk0XwuhKuttVHAKB0Zr+evAHPc1d+DKw3BM63lZWLwozuY1KQhHF WA1aVprwx7ll5C5lfRd+IL6J0J8WPQO6OMWu+u/p24GktdaZmqfbHH1+F A2nBATXSQkUp4heXJ7rRyG4hdzfr/XYQ7q1+p9Hu6AH4g5QZz1YtViYP7 ZPFBPw+FLckwEKxEnwRXvFKsocG6J9OZFqKK6K9h+n7JSUYxfzzs+SzhQ VBlyJYUPHYX95SODlMk1WBJTybECM+u4DQxRBEhWzGC1Vhp0tZRuAFJfq A==; X-IronPort-AV: E=McAfee;i="6600,9927,10795"; a="350449312" X-IronPort-AV: E=Sophos;i="6.01,156,1684825200"; d="scan'208";a="350449312" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Aug 2023 08:35:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10795"; a="855126978" X-IronPort-AV: E=Sophos;i="6.01,156,1684825200"; d="scan'208";a="855126978" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by orsmga004.jf.intel.com with ESMTP; 08 Aug 2023 08:35:13 -0700 From: Yi Liu To: joro@8bytes.org, alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com, robin.murphy@arm.com, baolu.lu@linux.intel.com Cc: 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, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, zhenzhong.duan@intel.com Subject: [PATCH v6 3/4] iommufd: Add IOMMU_GET_HW_INFO Date: Tue, 8 Aug 2023 08:35:09 -0700 Message-Id: <20230808153510.4170-4-yi.l.liu@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230808153510.4170-1-yi.l.liu@intel.com> References: <20230808153510.4170-1-yi.l.liu@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Under nested IOMMU translation, userspace owns the stage-1 translation table (e.g. the stage-1 page table of Intel VT-d or the context table of ARM SMMUv3, and etc.). Stage-1 translation tables are vendor specific, and need to be compatible with the underlying IOMMU hardware. Hence, userspace should know the IOMMU hardware capability before creating and configuring the stage-1 translation table to kernel. This adds IOMMU_GET_HW_INFO ioctl to query the IOMMU hardware information (a.k.a capability) for a given device. The returned data is vendor specific, userspace needs to decode it with the structure mapped by the @out_data_type field. As only physical devices have IOMMU hardware, so this will return error if the given device is not a physical device. Reviewed-by: Lu Baolu Co-developed-by: Nicolin Chen Signed-off-by: Nicolin Chen Signed-off-by: Yi Liu --- drivers/iommu/iommufd/main.c | 97 ++++++++++++++++++++++++++++++++++++ include/uapi/linux/iommufd.h | 36 +++++++++++++ 2 files changed, 133 insertions(+) diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c index 94c498b8fdf6..54e61fbf56f8 100644 --- a/drivers/iommu/iommufd/main.c +++ b/drivers/iommu/iommufd/main.c @@ -17,6 +17,7 @@ #include #include #include +#include "../iommu-priv.h" #include "io_pagetable.h" #include "iommufd_private.h" @@ -177,6 +178,99 @@ static int iommufd_destroy(struct iommufd_ucmd *ucmd) return 0; } +static int iommufd_zero_fill_user(void __user *ptr, size_t bytes) +{ + int index = 0; + + for (; index < bytes; index++) { + if (put_user(0, (uint8_t __user *)(ptr + index))) + return -EFAULT; + } + return 0; +} + +static int iommufd_fill_hw_info(struct device *dev, void __user *user_ptr, + unsigned int *length, u32 *type) +{ + const struct iommu_ops *ops; + unsigned int data_len; + void *data; + int rc = 0; + + ops = dev_iommu_ops(dev); + if (!ops->hw_info) { + *length = 0; + *type = IOMMU_HW_INFO_TYPE_NONE; + return 0; + } + + data = ops->hw_info(dev, &data_len, type); + if (IS_ERR(data)) + return PTR_ERR(data); + + /* + * drivers that have hw_info callback should have a unique + * iommu_hw_info_type. + */ + if (WARN_ON_ONCE(*type == IOMMU_HW_INFO_TYPE_NONE)) { + rc = -ENODEV; + goto err_free; + } + + *length = min(*length, data_len); + if (copy_to_user(user_ptr, data, *length)) { + rc = -EFAULT; + goto err_free; + } + +err_free: + kfree(data); + return rc; +} + +static int iommufd_get_hw_info(struct iommufd_ucmd *ucmd) +{ + struct iommu_hw_info *cmd = ucmd->cmd; + unsigned int length = cmd->data_len; + struct iommufd_device *idev; + void __user *user_ptr; + u32 hw_info_type; + int rc = 0; + + if (cmd->flags || cmd->__reserved || !cmd->data_len) + return -EOPNOTSUPP; + + idev = iommufd_get_device(ucmd, cmd->dev_id); + if (IS_ERR(idev)) + return PTR_ERR(idev); + + user_ptr = u64_to_user_ptr(cmd->data_ptr); + + rc = iommufd_fill_hw_info(idev->dev, user_ptr, + &length, &hw_info_type); + if (rc) + goto err_put; + + /* + * Zero the trailing bytes if the user buffer is bigger than the + * data size kernel actually has. + */ + if (length < cmd->data_len) { + rc = iommufd_zero_fill_user(user_ptr + length, + cmd->data_len - length); + if (rc) + goto err_put; + } + + cmd->data_len = length; + cmd->out_data_type = hw_info_type; + rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd)); + +err_put: + iommufd_put_object(&idev->obj); + return rc; +} + static int iommufd_fops_open(struct inode *inode, struct file *filp) { struct iommufd_ctx *ictx; @@ -265,6 +359,7 @@ static int iommufd_option(struct iommufd_ucmd *ucmd) union ucmd_buffer { struct iommu_destroy destroy; + struct iommu_hw_info info; struct iommu_hwpt_alloc hwpt; struct iommu_ioas_alloc alloc; struct iommu_ioas_allow_iovas allow_iovas; @@ -297,6 +392,8 @@ struct iommufd_ioctl_op { } static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = { IOCTL_OP(IOMMU_DESTROY, iommufd_destroy, struct iommu_destroy, id), + IOCTL_OP(IOMMU_GET_HW_INFO, iommufd_get_hw_info, struct iommu_hw_info, + __reserved), IOCTL_OP(IOMMU_HWPT_ALLOC, iommufd_hwpt_alloc, struct iommu_hwpt_alloc, __reserved), IOCTL_OP(IOMMU_IOAS_ALLOC, iommufd_ioas_alloc_ioctl, diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h index ac11ace21edb..4a00f8fb2d54 100644 --- a/include/uapi/linux/iommufd.h +++ b/include/uapi/linux/iommufd.h @@ -46,6 +46,7 @@ enum { IOMMUFD_CMD_OPTION, IOMMUFD_CMD_VFIO_IOAS, IOMMUFD_CMD_HWPT_ALLOC, + IOMMUFD_CMD_GET_HW_INFO, }; /** @@ -379,4 +380,39 @@ struct iommu_hwpt_alloc { enum iommu_hw_info_type { IOMMU_HW_INFO_TYPE_NONE, }; + +/** + * struct iommu_hw_info - ioctl(IOMMU_GET_HW_INFO) + * @size: sizeof(struct iommu_hw_info) + * @flags: Must be 0 + * @dev_id: The device bound to the iommufd + * @data_len: Input the length of the user buffer in bytes. Output the length + * of data filled in the user buffer. + * @data_ptr: Pointer to the user buffer + * @out_data_type: Output the iommu hardware info type as defined in the enum + * iommu_hw_info_type. + * @__reserved: Must be 0 + * + * Query the hardware information from an iommu behind a given device that has + * been bound to iommufd. @data_len is the size of the buffer, which captures an + * iommu type specific input data and a filled output data. Trailing bytes will + * be zeroed if the user buffer is larger than the data kernel has. + * + * The type specific data would be used to sync capabilities between the virtual + * IOMMU and the hardware IOMMU, e.g. a nested translation setup needs to check + * the hardware information, so the guest stage-1 page table will be compatible. + * + * The @out_data_type will be filled if the ioctl succeeds. It would be used to + * decode the data filled in the buffer pointed by @data_ptr. + */ +struct iommu_hw_info { + __u32 size; + __u32 flags; + __u32 dev_id; + __u32 data_len; + __aligned_u64 data_ptr; + __u32 out_data_type; + __u32 __reserved; +}; +#define IOMMU_GET_HW_INFO _IO(IOMMUFD_TYPE, IOMMUFD_CMD_GET_HW_INFO) #endif