Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:4 as permitted sender) client-ip=2620:137:e000::3:4;
Date:   Tue, 24 Oct 2023 13:31:30 -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 05/10] iommufd: Derive iommufd_hwpt_paging from
 iommufd_hw_pagetable
Message-ID: <20231024163130.GM3952@nvidia.com>
References: <20231024150609.46884-1-yi.l.liu@intel.com>
 <20231024150609.46884-6-yi.l.liu@intel.com>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20231024150609.46884-6-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?1Its1zLgU3rNDp4pXIbq/Z0Uhtcg/Xgj8QV5ntj4NdSI3TlDpMryCEQ8bXmH?=
 =?us-ascii?Q?lkrWoVPPT82G3/j8yFvhZZcHeIRGeUmWSTmaiAo9JHSDRAjBerJfPKoJxzlk?=
 =?us-ascii?Q?4Z0xoqAUALYolRJKXQjA6YTCEfD3NzU5f2eAYviQeXH8VPUNKtpZwxEDbHbM?=
 =?us-ascii?Q?0OBZ9evpzyWcOuPiIzB1lZZp0EVZjA/zo0vp2g09zaOC/2AVejDzuqND3q3Q?=
 =?us-ascii?Q?tmwXyVS+5A3SekpfmRY7KJWphkMp87gvCQ0/vIueUwI6wIDYQzAKx9Zl2Pck?=
 =?us-ascii?Q?aln39ibtwJpVjD6LZCRh/wwK182K7z9zACP/tYZ3I8bAiUTe8AG0nkM3PQB8?=
 =?us-ascii?Q?Mw11jC54YJTKsBxP0gYGajO/Py2sFc50PabCg6UaqO/c2CHQrwFToMsrSkfk?=
 =?us-ascii?Q?1G0MYUniED3e6WcgGyScSpCXvFrCznzi+9SBLj3fRx8Rs/nFIrRzb40btqi/?=
 =?us-ascii?Q?td+oSkH7U+tBztaICYvtd1wiraR5bgRWNYfVzXL0BMJtS2tz6zJFQrrRr8vT?=
 =?us-ascii?Q?2svcYk6SckptvKPGN2hyEv3Az0QWBK02j+461K30uuqbSA+AwcLQRVZoe4U2?=
 =?us-ascii?Q?aaRHdn8iAqFY2wuMlErlNJelevXoujaZQJQKUB16NMIzsx3QY0ogM6psZYLt?=
 =?us-ascii?Q?U0dC0wiXbODT7m92skkcpdfRtwr0YQ6rCwzVpUkT7fIlRf4m4C+ZlTt5Ccfr?=
 =?us-ascii?Q?7EWli3TEZHIGdPgpJRBswrE8zWDtPtBytxnuq5p8YJ8Zhk0QWt921mTDWsTn?=
 =?us-ascii?Q?nD8RChsWF02Zo9hjNmHxs7qGMEfmpmxV1U0284XAz2Uec6nRg4vtZtnRKhMZ?=
 =?us-ascii?Q?PHV5v7dGlPdYbxPHAeEjTHSJgwbf7Y66/5W+rVsWEaxY5kVc7eTg2VBM4UTj?=
 =?us-ascii?Q?/ovsMaDpE56fZYc8fJdF3vZZoeF4o8e7c5EyBygkSKlZvc0dPEamgYKLjPlM?=
 =?us-ascii?Q?qZ3QxoKjeD0UsZcR4LV/Kpqx1gr5R7dEflB3Hi8kSJxLHxCpCFvzQ1E7dgkY?=
 =?us-ascii?Q?XvItX4sWQKxw2AmuxpbW1vAq2JzRowmvpGW/0dnZPTB6JDnKH2sBHmPlOciQ?=
 =?us-ascii?Q?XCKhuKrwIbCxC3o+/mLAdg+VL2+cK3WZsP2BMfXRfy2sEYY1LKPNdlW8PFIN?=
 =?us-ascii?Q?kARktNWS26mcJZTevvIhdYrs71bhgdtDIOw4MdF8sLNmeYHgyP7Sm/z4saYJ?=
 =?us-ascii?Q?Qf+Yq+xQY9ymJ2eHLGYPBmpdTkV4XAZrxI6b9uCu7Qkeaj8sohsBGlkbnhng?=
 =?us-ascii?Q?VFiBR+ss+H4cLSNUHfj/oJjCX81dtlb+yXMugbw6GCBXFuyv/7oipzEV4mp+?=
 =?us-ascii?Q?3zkfanzcxme9xUCLP/aH8SJBsm8/p19odkZDuVs3vaXlglyWAs1ILLWfWVK9?=
 =?us-ascii?Q?U86bPcJqVgDcdlcBusiw+LgGiOIMpJ1HJobsDf8hSM5TAMPQWI9ZqlIqBBbW?=
 =?us-ascii?Q?mP69Hd3Z7zyZneO5NgKVHIYZAVkqY4qcGU7EfngWo+auDIixfPz9WoaYwrcP?=
 =?us-ascii?Q?UgmjM1RUb4vmnX0J0aFhJRTt+Et2YCVM8Ju/GK+KvYt2Fj5aNNwoF+7C06KW?=
 =?us-ascii?Q?rilFZdqkcE/rXMwSIESVyllsG3sEdH6fnG6ArLSk?=
X-OriginatorOrg: Nvidia.com
X-MS-Exchange-CrossTenant-Network-Message-Id: cfb70415-7be8-4a9f-f30d-08dbd4aeae95
X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Oct 2023 16:31:32.3070
 (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: LUOBIsuj5wD7/KkOirHPpi7jSgfogAJJa0l+beFXhUIH3YJp6cJu7VIidDFsJf1D
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR12MB6873
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 howler.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 (howler.vger.email [0.0.0.0]); Tue, 24 Oct 2023 09:32:06 -0700 (PDT)

On Tue, Oct 24, 2023 at 08:06:04AM -0700, Yi Liu wrote:

>  static int iommufd_group_do_replace_paging(struct iommufd_group *igroup,
> -					   struct iommufd_hw_pagetable *hwpt)
> +					   struct iommufd_hwpt_paging *hwpt_paging)
>  {
>  	struct iommufd_hw_pagetable *old_hwpt = igroup->hwpt;
>  	struct iommufd_device *cur;
> @@ -441,22 +447,23 @@ static int iommufd_group_do_replace_paging(struct iommufd_group *igroup,
>  
>  	lockdep_assert_held(&igroup->lock);
>  
> -	if (hwpt_is_paging(old_hwpt) && hwpt->ioas != old_hwpt->ioas) {
> +	if (hwpt_is_paging(old_hwpt) &&
> +	    hwpt_paging->ioas != to_hwpt_paging(old_hwpt)->ioas) {
>  		list_for_each_entry(cur, &igroup->device_list, group_item) {
>  			rc = iopt_table_enforce_dev_resv_regions(
> -				&hwpt->ioas->iopt, cur->dev, NULL);
> +				&hwpt_paging->ioas->iopt, cur->dev, NULL);
>  			if (rc)
>  				goto err_unresv;
>  		}
>  	}
>  
> -	rc = iommufd_group_setup_msi(igroup, hwpt);
> +	rc = iommufd_group_setup_msi(igroup, hwpt_paging);
>  	if (rc)
>  		goto err_unresv;
>  	return 0;
>  
>  err_unresv:
> -	iommufd_group_remove_reserved_iova(igroup, hwpt);
> +	iommufd_group_remove_reserved_iova(igroup, hwpt_paging);
>  	return rc;
>  }
>  
> @@ -482,7 +489,8 @@ iommufd_device_do_replace(struct iommufd_device *idev,
>  	}
>  
>  	if (hwpt_is_paging(hwpt)) {
> -		rc = iommufd_group_do_replace_paging(igroup, hwpt);
> +		rc = iommufd_group_do_replace_paging(igroup,
> +						     to_hwpt_paging(hwpt));
>  		if (rc)
>  			goto err_unlock;
>  	}
> @@ -493,8 +501,10 @@ iommufd_device_do_replace(struct iommufd_device *idev,
>  
>  	old_hwpt = igroup->hwpt;
>  	if (hwpt_is_paging(old_hwpt) &&
> -	    (!hwpt_is_paging(hwpt) || hwpt->ioas != old_hwpt->ioas))
> -		iommufd_group_remove_reserved_iova(igroup, old_hwpt);
> +	    (!hwpt_is_paging(hwpt) ||
> +	     to_hwpt_paging(hwpt)->ioas != to_hwpt_paging(old_hwpt)->ioas))
> +		iommufd_group_remove_reserved_iova(igroup,
> +						   to_hwpt_paging(old_hwpt));
>  
>  	igroup->hwpt = hwpt;
>  
> @@ -513,7 +523,8 @@ iommufd_device_do_replace(struct iommufd_device *idev,
>  	return old_hwpt;
>  err_unresv:
>  	if (hwpt_is_paging(hwpt))
> -		iommufd_group_remove_reserved_iova(igroup, hwpt);
> +		iommufd_group_remove_reserved_iova(igroup,
> +						   to_hwpt_paging(old_hwpt));

This gets a compiler warning:

../drivers/iommu/iommufd/device.c:527:25: warning: variable 'old_hwpt' is uninitialized when used here [-Wuninitialized]
                                                   to_hwpt_paging(old_hwpt));
                                                                  ^~~~~~~~
../drivers/iommu/iommufd/device.c:475:39: note: initialize the variable 'old_hwpt' to silence this warning
        struct iommufd_hw_pagetable *old_hwpt;
                                             ^
                                              = NULL

I fixed it with:

--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -488,6 +488,7 @@ iommufd_device_do_replace(struct iommufd_device *idev,
                return NULL;
        }
 
+       old_hwpt = igroup->hwpt;
        if (hwpt_is_paging(hwpt)) {
                rc = iommufd_group_do_replace_paging(igroup,
                                                     to_hwpt_paging(hwpt));
@@ -499,7 +500,6 @@ iommufd_device_do_replace(struct iommufd_device *idev,
        if (rc)
                goto err_unresv;
 
-       old_hwpt = igroup->hwpt;
        if (hwpt_is_paging(old_hwpt) &&
            (!hwpt_is_paging(hwpt) ||
             to_hwpt_paging(hwpt)->ioas != to_hwpt_paging(old_hwpt)->ioas))

Jason