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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A432C6FD1F for ; Thu, 9 Mar 2023 13:53:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231407AbjCINxL (ORCPT ); Thu, 9 Mar 2023 08:53:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231315AbjCINwn (ORCPT ); Thu, 9 Mar 2023 08:52:43 -0500 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10CD619109; Thu, 9 Mar 2023 05:52:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1678369940; x=1709905940; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=Ip+6Qn6pHtw8f5LnG0WQBpWF3slJzUO6nkNpuzd32f8=; b=mWih5aCxCmTumWemjlBVROPuPI/+Jgfg19d6G+fRvwpE6Sd6KtID5Blq O+WY+immxEh3jcQFklsFfM0/Cx14PPBa7Z+npqWYac0WqK+n5pqDbqJhW qvSiLNu527moe7Yo7KwR1FHDmBP24jyun3nYiS8hz/LWXOCY4wlvFAJr/ Opyhyr8l2v087hB+dxfb2WcOj7wCjKuzoInCyGlm5XHT8sX34Af6P3djw sfV7nfX97auXAt8esitAHKMOIZxgCF4pYHO2DPhUTyFNQRdfo3hE07o4i 2cd3+nV+nTMtNY5K6FW+WgBSGl5YG6WFv3JSzvMqEihKBlH4hKBW48JJQ A==; X-IronPort-AV: E=McAfee;i="6500,9779,10643"; a="338783674" X-IronPort-AV: E=Sophos;i="5.98,246,1673942400"; d="scan'208";a="338783674" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Mar 2023 05:50:26 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10643"; a="670731316" X-IronPort-AV: E=Sophos;i="5.98,246,1673942400"; d="scan'208";a="670731316" Received: from blu2-mobl.ccr.corp.intel.com (HELO [10.254.210.74]) ([10.254.210.74]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Mar 2023 05:50:20 -0800 Message-ID: <6c1b221e-df8d-4b82-10e5-aa3027819d45@linux.intel.com> Date: Thu, 9 Mar 2023 21:50:18 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Cc: baolu.lu@linux.intel.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.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 Subject: Re: [PATCH v2 3/4] iommufd: Add IOMMU_DEVICE_GET_HW_INFO Content-Language: en-US To: Yi Liu , joro@8bytes.org, alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com, robin.murphy@arm.com References: <20230309075358.571567-1-yi.l.liu@intel.com> <20230309075358.571567-4-yi.l.liu@intel.com> From: Baolu Lu In-Reply-To: <20230309075358.571567-4-yi.l.liu@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/3/9 15:53, Yi Liu wrote: > 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 needs to be compatiable 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_DEVICE_GET_HW_INFO to query the IOMMU hardware information > 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. > > Co-developed-by: Nicolin Chen > Signed-off-by: Nicolin Chen > Signed-off-by: Yi Liu > --- > drivers/iommu/iommufd/device.c | 74 +++++++++++++++++++++++++ > drivers/iommu/iommufd/iommufd_private.h | 1 + > drivers/iommu/iommufd/main.c | 3 + > include/uapi/linux/iommufd.h | 40 +++++++++++++ > 4 files changed, 118 insertions(+) > > diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c > index c10e02f6a0be..6948539488a5 100644 > --- a/drivers/iommu/iommufd/device.c > +++ b/drivers/iommu/iommufd/device.c > @@ -257,6 +257,80 @@ struct iommufd_ctx *iommufd_device_to_ictx(struct iommufd_device *idev) > } > EXPORT_SYMBOL_NS_GPL(iommufd_device_to_ictx, IOMMUFD); > > +static int iommufd_zero_fill_user(u64 ptr, int bytes) > +{ > + int index = 0; > + > + for (; index < bytes; index++) { > + if (put_user(0, (uint8_t __user *)(ptr + index))) > + return -EFAULT; > + } > + return 0; > +} > + > +int iommufd_device_get_hw_info(struct iommufd_ucmd *ucmd) > +{ > + struct iommu_hw_info *cmd = ucmd->cmd; > + struct iommufd_device *idev; > + const struct iommu_ops *ops; > + void *data; > + unsigned int length, data_len; > + int rc; Reverse christmas tree order for declarations. > + > + 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); > + > + ops = dev_iommu_ops(idev->dev); > + if (!ops || !ops->hw_info) { dev_iommu_ops() will never return a NULL. Need below check dev->iommu && dev->iommu->iommu_dev before dev_iommu_ops(). Perhaps something like below? if (!dev->iommu || !dev->iommu->iommu_dev) return -EINVAL; ops = dev_iommu_ops(idev->dev); if (!ops->hw_info) return -ENODEV; > + rc = -EOPNOTSUPP; > + goto out_put; > + } > + > + /* driver has hw_info callback should have a unique driver_type */ > + if (WARN_ON(ops->driver_type == IOMMU_HW_INFO_TYPE_DEFAULT)) { If so, perhaps IOMMU_HW_INFO_TYPE_INVALID is more readable? I'm not sure if a calltrace is really necessary here. If not, perhaps, if (ops->driver_type == IOMMU_HW_INFO_TYPE_DEFAULT) { pr_warn_ratelimited("iommu driver set an invalid type\n"); rc = -ENODEV; goto out_put; } > + rc = -EOPNOTSUPP; > + goto out_put; > + } > + > + data = ops->hw_info(idev->dev, &data_len); > + if (IS_ERR(data)) { > + rc = PTR_ERR(data); > + goto out_put; > + } > + > + length = min(cmd->data_len, data_len); > + if (copy_to_user(u64_to_user_ptr(cmd->data_ptr), data, length)) { > + rc = -EFAULT; > + goto out_free_data; > + } > + > + /* > + * 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(cmd->data_ptr + length, > + cmd->data_len - length); > + if (rc) > + goto out_free_data; > + } > + > + cmd->out_data_type = ops->driver_type; > + cmd->data_len = length; > + > + rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd)); > + > +out_free_data: > + kfree(data); > +out_put: > + iommufd_put_object(&idev->obj); > + return rc; > +} > + > static int iommufd_group_setup_msi(struct iommufd_group *igroup, > struct iommufd_hw_pagetable *hwpt) > { > diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h > index b18f843ad6a4..05b5ad66f716 100644 > --- a/drivers/iommu/iommufd/iommufd_private.h > +++ b/drivers/iommu/iommufd/iommufd_private.h > @@ -307,6 +307,7 @@ iommufd_get_device(struct iommufd_ucmd *ucmd, u32 id) > } > > void iommufd_device_destroy(struct iommufd_object *obj); > +int iommufd_device_get_hw_info(struct iommufd_ucmd *ucmd); > > struct iommufd_access { > struct iommufd_object obj; > diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c > index 694da191e4b1..f079c0bda46b 100644 > --- a/drivers/iommu/iommufd/main.c > +++ b/drivers/iommu/iommufd/main.c > @@ -262,6 +262,7 @@ static int iommufd_option(struct iommufd_ucmd *ucmd) > union ucmd_buffer { > struct iommu_destroy destroy; > struct iommu_hwpt_alloc hwpt; > + struct iommu_hw_info info; > struct iommu_ioas_alloc alloc; > struct iommu_ioas_allow_iovas allow_iovas; > struct iommu_ioas_copy ioas_copy; > @@ -295,6 +296,8 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = { > IOCTL_OP(IOMMU_DESTROY, iommufd_destroy, struct iommu_destroy, id), > IOCTL_OP(IOMMU_HWPT_ALLOC, iommufd_hwpt_alloc, struct iommu_hwpt_alloc, > __reserved), > + IOCTL_OP(IOMMU_DEVICE_GET_HW_INFO, iommufd_device_get_hw_info, > + struct iommu_hw_info, __reserved), > IOCTL_OP(IOMMU_IOAS_ALLOC, iommufd_ioas_alloc_ioctl, > struct iommu_ioas_alloc, out_ioas_id), > IOCTL_OP(IOMMU_IOAS_ALLOW_IOVAS, iommufd_ioas_allow_iovas, > diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h > index 955cbef640da..4ac525897b82 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_DEVICE_GET_HW_INFO, > }; > > /** > @@ -377,4 +378,43 @@ struct iommu_hwpt_alloc { > enum iommu_hw_info_type { > IOMMU_HW_INFO_TYPE_DEFAULT, > }; > + > +/** > + * struct iommu_hw_info - ioctl(IOMMU_DEVICE_GET_HW_INFO) > + * @size: sizeof(struct iommu_hw_info) > + * @flags: Must be 0 > + * @dev_id: The device being attached to the iommufd > + * @data_len: Input the length of the user buffer in bytes. Output the > + * length of data filled to the user buffer. > + * @data_ptr: Pointer to the type specific structure > + * @out_data_type: Output the iommu hardware info type, it is one of > + * enum iommu_hw_info_type. > + * @__reserved: Must be 0 > + * > + * Query the hardware iommu information for given device which has been > + * bound to iommufd. @data_len is the size of the buffer which captures > + * iommu type specific data and the data will be filled. Trailing bytes > + * are zeroed if the user buffer is larger than the data kernel has. > + * > + * The type specific data would be used to sync capability between the > + * vIOMMU and the hardware IOMMU. e.g. nested translation requires to > + * check the hardware IOMMU capability, since a stage-1 translation table > + * is owned by user but used by hardware IOMMU. > + * > + * 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. > + * > + * This is only available for the physical devices bound to iommufd as > + * only physical devices can have hardware IOMMU. > + */ > +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_DEVICE_GET_HW_INFO _IO(IOMMUFD_TYPE, IOMMUFD_CMD_DEVICE_GET_HW_INFO) > #endif Other look good to me. Best regards, baolu