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 57AA5C0015E for ; Fri, 4 Aug 2023 01:59:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231797AbjHDB7Y (ORCPT ); Thu, 3 Aug 2023 21:59:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229560AbjHDB7Y (ORCPT ); Thu, 3 Aug 2023 21:59:24 -0400 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6B0834486; Thu, 3 Aug 2023 18:59:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1691114362; x=1722650362; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=qPJ6wVTEhN0Xm5LsPItjDidUz03aXajdt1tgXSztyNE=; b=Urw/NBYIZsRUPwPPGIoRxnyqCx1roihO8l5FVm+QPa2XB9NDj1X4SFhQ ooFj/tmZY9+pcHkKghV8VE84O9a5p3gGp7Ly7cv/1oq9Y1vafmbNOr+oZ KeMb1Lus43koE0qnpLxAFgn8yiNSjdxC7He6By9uij8k79pvKQsjg5pA8 RCYlaKl65hEIZXIjcYW3K6njWslWgKZPL1mNlAfeNnhzfTrqPOYF7mScA T3O1V9S+zL/PoQxcerPl0j12cibFvkRW/IYeLqHprFplw/SbeuUVb1rdK 0ODpp2pUnFSLSVLg3oCkYiDJjEqx0rnNIOIw0BrWg9A/fCpgPv1d5AK15 A==; X-IronPort-AV: E=McAfee;i="6600,9927,10791"; a="349633842" X-IronPort-AV: E=Sophos;i="6.01,253,1684825200"; d="scan'208";a="349633842" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Aug 2023 18:59:21 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10791"; a="723455022" X-IronPort-AV: E=Sophos;i="6.01,253,1684825200"; d="scan'208";a="723455022" Received: from blu2-mobl.ccr.corp.intel.com (HELO [10.254.210.88]) ([10.254.210.88]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Aug 2023 18:59:14 -0700 Message-ID: <51418f60-db2f-8ee3-ed9c-1a97d89774cf@linux.intel.com> Date: Fri, 4 Aug 2023 09:59:11 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 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, zhenzhong.duan@intel.com Subject: Re: [PATCH v5 3/4] iommufd: Add IOMMU_GET_HW_INFO To: Yi Liu , joro@8bytes.org, alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com, robin.murphy@arm.com References: <20230803143144.200945-1-yi.l.liu@intel.com> <20230803143144.200945-4-yi.l.liu@intel.com> Content-Language: en-US From: Baolu Lu In-Reply-To: <20230803143144.200945-4-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-kselftest@vger.kernel.org On 2023/8/3 22:31, 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 need to be compatiable with the underlying IOMMU hardware. Hence, compatible > 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. > > Co-developed-by: Nicolin Chen > Signed-off-by: Nicolin Chen > Signed-off-by: Yi Liu > --- > drivers/iommu/iommufd/main.c | 79 ++++++++++++++++++++++++++++++++++++ > include/uapi/linux/iommufd.h | 36 ++++++++++++++++ > 2 files changed, 115 insertions(+) > > diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c > index 94c498b8fdf6..a0302bcaa97c 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 +178,81 @@ 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_get_hw_info(struct iommufd_ucmd *ucmd) > +{ > + u32 hw_info_type = IOMMU_HW_INFO_TYPE_NONE; > + struct iommu_hw_info *cmd = ucmd->cmd; > + unsigned int length = 0, data_len; > + struct iommufd_device *idev; > + const struct iommu_ops *ops; > + void __user *user_ptr; > + void *data = NULL; > + 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); > + > + ops = dev_iommu_ops(idev->dev); > + if (!ops->hw_info) > + goto done; > + > + data = ops->hw_info(idev->dev, &data_len, &hw_info_type); > + if (IS_ERR(data)) { > + rc = PTR_ERR(data); > + goto out_err; Can kfree() handle a ERR_PTR input? I am afraid not, /** * kfree - free previously allocated memory * @object: pointer returned by kmalloc() or kmem_cache_alloc() * * If @object is NULL, no operation is performed. */ void kfree(const void *object) { struct folio *folio; struct slab *slab; struct kmem_cache *s; trace_kfree(_RET_IP_, object); if (unlikely(ZERO_OR_NULL_PTR(object))) return; So, perhaps we should add data = NULL; before goto out_err; ? > + } > + > + /* driver has hw_info callback should have a unique hw_info_type */ > + if (WARN_ON_ONCE(hw_info_type == IOMMU_HW_INFO_TYPE_NONE)) { > + rc = -ENODEV; > + goto out_err; > + } > + > + length = min(cmd->data_len, data_len); > + if (copy_to_user(user_ptr, data, length)) { > + rc = -EFAULT; > + goto out_err; > + } > + > +done: > + /* > + * 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 out_err; > + } > + > + cmd->data_len = length; > + cmd->out_data_type = hw_info_type; > + rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd)); > + > +out_err: > + kfree(data); > + iommufd_put_object(&idev->obj); > + return rc; > +} > + Others look good to me, feel free to add: Reviewed-by: Lu Baolu after above are addressed. Best regards, baolu