Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) client-ip=23.128.96.32;
Date:   Tue, 24 Oct 2023 14:13:12 -0300
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Yi Liu <yi.l.liu@intel.com>
Cc:     joro@8bytes.org, alex.williamson@redhat.com, kevin.tian@intel.com,
        robin.murphy@arm.com, 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, joao.m.martins@oracle.com
Subject: Re: [PATCH v6 07/10] iommufd: Add a nested HW pagetable object
Message-ID: <20231024171312.GN3952@nvidia.com>
References: <20231024150609.46884-1-yi.l.liu@intel.com>
 <20231024150609.46884-8-yi.l.liu@intel.com>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20231024150609.46884-8-yi.l.liu@intel.com>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?jZwF40CtG1GxoNtTObjpRGxFWvko2PHxmPsQF7FR4JynOO63+vCsDmtehmzr?=
 =?us-ascii?Q?3WS6xL87LWtrq3hjME0PU/g33Dv8PZ3JzOzCpk/0zWzNEQiFXk5BNNZSj8uc?=
 =?us-ascii?Q?Hm7A5tW2oFaPMXn46orzsBc3J61E/g9VUjet6vEc+1hKTmKvLWWysbJXXur8?=
 =?us-ascii?Q?PAOHDmxToxD+LzR4/OxN7xVTHO6IUmcwWWlNO55JJ8leMgsoNBg5JnP7f85T?=
 =?us-ascii?Q?KVJl+4WcPZfZngQhgUtNz3lecYsU8jkCEZPOLuwREagANfHx4jMyv2xvmvzZ?=
 =?us-ascii?Q?4TU1HsB8qAStJzxvCyY/u1zyTbUSvR6HwmLGndx6aNmkLSh0KxfhkSmwIYT4?=
 =?us-ascii?Q?VlBItLfaTfLxH2mftgnBxnTM0xUxeDWRulL/RXpxd3Itnd2hMXkYJRAubV5j?=
 =?us-ascii?Q?P9uHuZ/kqwqbHYNxVBclMnCTHbn+pbfjYYBu+8jV7rrmL1dpa05aQAOBTeeN?=
 =?us-ascii?Q?H8iraetgUKaBule3NneZpCxgAVDTT+bzJU+5YvhIvwrylLSZvFDDrXYvuMeH?=
 =?us-ascii?Q?OoIvxrWPWW1TFJaHGnizcQXc8aFlAQjyGTwnrBgf9lIJdXMjMEsk8NLcdmfP?=
 =?us-ascii?Q?ODRxz1jhHR/XqoMn2tgHZuJ0JFQkb0VzD2eqWZDInPFRu+nSLR8k+3+sA05m?=
 =?us-ascii?Q?fnoupIc5OLcc552XpT8gL7TGVb25iMEpPkjgeiwzPsKQ99IW5zQzZuhruyJL?=
 =?us-ascii?Q?EZ1zdzplR4J4VlZ/v66nBcjZfV1FdyREQmx50bytGHEBJcKZlrngL1R/UID2?=
 =?us-ascii?Q?9d9fCq2Tz8D9L6K9TqMLjDAppFMtA3m1Le5w56GPywsMTvsNSLTWc8OKA8+U?=
 =?us-ascii?Q?ZyloQC2gCzAc3po9lgN42RA1JU+dp8Nwq7S9GCRQc2xSkJS+hC3cNdNsg3Yw?=
 =?us-ascii?Q?6yQL5Yxl9Sudc+F9KQjufzfBjDba99vSIzpaHK3Q5v9KY9riQgxHIdTrvEqf?=
 =?us-ascii?Q?m+Fdd7Sm4wNHNz2ahaXlS2bgqXjyw/uGZDCqelFugJHpN8F2uCVVS2QxIpN9?=
 =?us-ascii?Q?ctRwUHv7BgGz/8qsfbgzclmVN9ZbtVr/KA7AG9A4yRAPM7b1k5ZQ2mLHZoUx?=
 =?us-ascii?Q?QXyd1idF+OYrPPLwi/XF9Wq9+zFVdBBWMdgEAF+vLeSg4RCaaBhym2ayn+Us?=
 =?us-ascii?Q?D3y7n4MP3nJKLTHSFzzfMBrVTWQU73Vpd1jTBPX8uFQIGD1O5PG6RTWOUs/o?=
 =?us-ascii?Q?CLx5nSG1ayqA7NzrUyIw1y3pxszFuu8tvPogoQA5gk2F72+npFTxNaoEciBf?=
 =?us-ascii?Q?0YpBBx0DkGfb3b4JbbqOuthPEw2QFc4AsJn4kFL0uKj9Ol9GX22xOpS0Xcpr?=
 =?us-ascii?Q?qcj+JDc8iMrDylu8FlcPrlBJ48/hrfenNB9ZROxL/zHnUwmz/7YzTKHqOSoP?=
 =?us-ascii?Q?i+Xdo5B9JEsWI7drKXrmOh2aknqyGV4XVDgJ3jbczvwh+5tUtyYN2Sz+BY+F?=
 =?us-ascii?Q?OpjlhoTmQlsPDaMqRKptCPXkYANeOuQTu1C19dowGGH8CIPgLBHMY4XkThRt?=
 =?us-ascii?Q?fY48xpxc94k/j+7D1Spssw6yDdjnaBY4BodTd5sVEIUHlEQw9skhW8zKX0H0?=
 =?us-ascii?Q?zRX+bHHeJigoqzhF3MKdXerQ+pFt6eSfhv4Sjw3H?=
X-OriginatorOrg: Nvidia.com
X-MS-Exchange-CrossTenant-Network-Message-Id: d3095d42-2328-4a01-dd65-08dbd4b481ef
X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Oct 2023 17:13:14.3555
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: eNyHNYruIADH3Q5qu1k9rFt/t34HNUMnygL/OI1L7EHue0CzRsAdX/R3Ws7Yst46
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR12MB4111
X-Spam-Status: No, score=-0.9 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable
	autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on agentk.vger.email
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (agentk.vger.email [0.0.0.0]); Tue, 24 Oct 2023 10:13:34 -0700 (PDT)

On Tue, Oct 24, 2023 at 08:06:06AM -0700, Yi Liu wrote:
> +static struct iommufd_hwpt_nested *
> +iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx,
> +			  struct iommufd_hwpt_paging *parent,
> +			  struct iommufd_device *idev, u32 flags,
> +			  const struct iommu_user_data *user_data)
> +{
> +	const struct iommu_ops *ops = dev_iommu_ops(idev->dev);
> +	struct iommufd_hwpt_nested *hwpt_nested;
> +	struct iommufd_hw_pagetable *hwpt;
> +	int rc;
> +
> +	if (flags != 0)
> +		return ERR_PTR(-EOPNOTSUPP);
> +	if (!user_data)
> +		return ERR_PTR(-EINVAL);

user_data is never NULL now, I removed this

> +	if (user_data->type == IOMMU_HWPT_DATA_NONE)
> +		return ERR_PTR(-EINVAL);
> +	if (parent->auto_domain)
> +		return ERR_PTR(-EINVAL);
> +	if (!parent->nest_parent)
> +		return ERR_PTR(-EINVAL);

And put these all together

	if (flags || user_data->type == IOMMU_HWPT_DATA_NONE ||
	    !ops->domain_alloc_user)
		return ERR_PTR(-EOPNOTSUPP);
	if (parent->auto_domain || !parent->nest_parent)
		return ERR_PTR(-EINVAL);


> +
> +	if (!ops->domain_alloc_user)
> +		return ERR_PTR(-EOPNOTSUPP);
> +
> +	hwpt_nested = __iommufd_object_alloc(ictx, hwpt_nested,
> +					     IOMMUFD_OBJ_HWPT_NESTED,
> +					     common.obj);
> +	if (IS_ERR(hwpt_nested))
> +		return ERR_CAST(hwpt_nested);
> +	hwpt = &hwpt_nested->common;
> +
> +	refcount_inc(&parent->common.obj.users);
> +	hwpt_nested->parent = parent;
> +
> +	hwpt->domain = ops->domain_alloc_user(idev->dev, 0,

And we may as well pass flags here even though we know it is 0 today.

Jason