From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1CA85818 for ; Fri, 12 May 2023 05:39:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1683869948; x=1715405948; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=zC92a2N0m2Rf8NugNXwOSZnbIW4HBYFpSQTmsIkInWs=; b=fJdXAgEwuGpNpy1+scSIqGAcurWGYCDhCkIN7n0tITlDikiPqMFpzthP 76K3Y8qIGC3FevnFRiRxTejvtRcwEs5xM0Pi/bSdnYfh6ffU+vtbZxdA6 X19GMkgqBFmk9OeTNA8GnRqOOnXP19ODA8pcGUIJhVbraGJql28eH1+8v hFtzNM7Zhr1Ussk9T2HoAEj9C4coTpTO0koxx9Z+5GzF5kVEGZb9AKig2 eywp4nicoAYLrETODDlTjy3yAuVTKJkj+M+bfflUnJLGmlHXct0U8gs96 2+O956Qer6H5VFMIDTVgX13cfHaYp9GxhsnU+m3F30ltfnyqXScbc0tbr A==; X-IronPort-AV: E=McAfee;i="6600,9927,10707"; a="350734482" X-IronPort-AV: E=Sophos;i="5.99,269,1677571200"; d="scan'208";a="350734482" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 May 2023 22:39:07 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10707"; a="732893212" X-IronPort-AV: E=Sophos;i="5.99,269,1677571200"; d="scan'208";a="732893212" Received: from allen-box.sh.intel.com (HELO [10.239.159.127]) ([10.239.159.127]) by orsmga001.jf.intel.com with ESMTP; 11 May 2023 22:39:01 -0700 Message-ID: <6ab2d63e-4dcc-6562-9698-d23300c7d1ae@linux.intel.com> Date: Fri, 12 May 2023 13:38:31 +0800 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 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 v3 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: <20230511143024.19542-1-yi.l.liu@intel.com> <20230511143024.19542-4-yi.l.liu@intel.com> From: Baolu Lu In-Reply-To: <20230511143024.19542-4-yi.l.liu@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 5/11/23 10:30 PM, 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 | 72 +++++++++++++++++++++++++ > drivers/iommu/iommufd/iommufd_private.h | 1 + > drivers/iommu/iommufd/main.c | 3 ++ > include/uapi/linux/iommufd.h | 37 +++++++++++++ > 4 files changed, 113 insertions(+) > > diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c > index 051bd8e99858..bc99d092de8f 100644 > --- a/drivers/iommu/iommufd/device.c > +++ b/drivers/iommu/iommufd/device.c > @@ -263,6 +263,78 @@ u32 iommufd_device_to_id(struct iommufd_device *idev) > } > EXPORT_SYMBOL_NS_GPL(iommufd_device_to_id, 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 *)u64_to_user_ptr(ptr + index))) > + return -EFAULT; > + } > + return 0; > +} > + > +int iommufd_device_get_hw_info(struct iommufd_ucmd *ucmd) > +{ > + struct iommu_hw_info *cmd = ucmd->cmd; > + unsigned int length = 0, data_len; > + struct iommufd_device *idev; > + const struct iommu_ops *ops; > + 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); > + > + ops = dev_iommu_ops(idev->dev); > + if (!ops->hw_info) > + goto done; If the iommu driver doesn't provide a hw_info callback, it still returns success? > + > + /* driver has hw_info callback should have a unique hw_info_type */ > + if (ops->hw_info_type == IOMMU_HW_INFO_TYPE_NONE) { > + pr_warn_ratelimited("iommu driver set an invalid type\n"); > + rc = -ENODEV; > + goto out_err; > + } > + > + data = ops->hw_info(idev->dev, &data_len); > + if (IS_ERR(data)) { > + rc = PTR_ERR(data); > + goto out_err; > + } > + > + length = min(cmd->data_len, data_len); > + if (copy_to_user(u64_to_user_ptr(cmd->data_ptr), data, length)) { > + rc = -EFAULT; > + goto out_err; > + } > + > + /* > + * 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_err; > + } > + > +done: > + cmd->data_len = length; > + cmd->out_data_type = ops->hw_info_type; > + rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd)); > + > +out_err: > + kfree(data); > + iommufd_put_object(&idev->obj); > + return rc; > +} > + > static int iommufd_group_setup_msi(struct iommufd_group *igroup, > struct iommufd_hw_pagetable *hwpt) > { Best regards, baolu