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Mon, 15 May 2023 14:00:39 +0000 Received: from LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::f7a7:a561:87e9:5fab]) by LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::f7a7:a561:87e9:5fab%6]) with mapi id 15.20.6387.030; Mon, 15 May 2023 14:00:39 +0000 From: Jason Gunthorpe To: iommu@lists.linux.dev, linux-kselftest@vger.kernel.org Cc: Lu Baolu , Kevin Tian , kvm@vger.kernel.org, Lixiao Yang , Matthew Rosato , Nicolin Chen , Yi Liu Subject: [PATCH v7 02/19] iommufd: Add iommufd_group Date: Mon, 15 May 2023 11:00:17 -0300 Message-Id: <2-v7-6c0fd698eda2+5e3-iommufd_alloc_jgg@nvidia.com> In-Reply-To: <0-v7-6c0fd698eda2+5e3-iommufd_alloc_jgg@nvidia.com> References: X-ClientProxiedBy: MN2PR17CA0004.namprd17.prod.outlook.com (2603:10b6:208:15e::17) To LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV2PR12MB5869:EE_|SN7PR12MB7954:EE_ X-MS-Office365-Filtering-Correlation-Id: d8eb6471-8239-49f7-41f8-08db554cc16c X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 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 X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: d8eb6471-8239-49f7-41f8-08db554cc16c X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 May 2023 14:00:35.5900 (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: WcaeJ2IbxaprmBSHreYIwBkAJFTWXCNgc+P6YzG71Oz8qBmjSIC8nVZzP13id2El X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR12MB7954 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org When the hwpt to device attachment is fairly static we could get away with the simple approach of keeping track of the groups via a device list. But with replace this is infeasible. Add an automatically managed struct that is 1:1 with the iommu_group per-ictx so we can store the necessary tracking information there. Reviewed-by: Lu Baolu Reviewed-by: Kevin Tian Signed-off-by: Jason Gunthorpe --- drivers/iommu/iommufd/device.c | 141 +++++++++++++++++++++--- drivers/iommu/iommufd/iommufd_private.h | 9 +- drivers/iommu/iommufd/main.c | 2 + 3 files changed, 135 insertions(+), 17 deletions(-) diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index 927f2051715f64..8c27f6901446e8 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -15,13 +15,121 @@ MODULE_PARM_DESC( "Allow IOMMUFD to bind to devices even if the platform cannot isolate " "the MSI interrupt window. Enabling this is a security weakness."); +static void iommufd_group_release(struct kref *kref) +{ + struct iommufd_group *igroup = + container_of(kref, struct iommufd_group, ref); + + xa_cmpxchg(&igroup->ictx->groups, iommu_group_id(igroup->group), igroup, + NULL, GFP_KERNEL); + iommu_group_put(igroup->group); + kfree(igroup); +} + +static void iommufd_put_group(struct iommufd_group *group) +{ + kref_put(&group->ref, iommufd_group_release); +} + +static bool iommufd_group_try_get(struct iommufd_group *igroup, + struct iommu_group *group) +{ + if (!igroup) + return false; + /* + * group ID's cannot be re-used until the group is put back which does + * not happen if we could get an igroup pointer under the xa_lock. + */ + if (WARN_ON(igroup->group != group)) + return false; + return kref_get_unless_zero(&igroup->ref); +} + +/* + * iommufd needs to store some more data for each iommu_group, we keep a + * parallel xarray indexed by iommu_group id to hold this instead of putting it + * in the core structure. To keep things simple the iommufd_group memory is + * unique within the iommufd_ctx. This makes it easy to check there are no + * memory leaks. + */ +static struct iommufd_group *iommufd_get_group(struct iommufd_ctx *ictx, + struct device *dev) +{ + struct iommufd_group *new_igroup; + struct iommufd_group *cur_igroup; + struct iommufd_group *igroup; + struct iommu_group *group; + unsigned int id; + + group = iommu_group_get(dev); + if (!group) + return ERR_PTR(-ENODEV); + + id = iommu_group_id(group); + + xa_lock(&ictx->groups); + igroup = xa_load(&ictx->groups, id); + if (iommufd_group_try_get(igroup, group)) { + xa_unlock(&ictx->groups); + iommu_group_put(group); + return igroup; + } + xa_unlock(&ictx->groups); + + new_igroup = kzalloc(sizeof(*new_igroup), GFP_KERNEL); + if (!new_igroup) { + iommu_group_put(group); + return ERR_PTR(-ENOMEM); + } + + kref_init(&new_igroup->ref); + /* group reference moves into new_igroup */ + new_igroup->group = group; + + /* + * The ictx is not additionally refcounted here becase all objects using + * an igroup must put it before their destroy completes. + */ + new_igroup->ictx = ictx; + + /* + * We dropped the lock so igroup is invalid. NULL is a safe and likely + * value to assume for the xa_cmpxchg algorithm. + */ + cur_igroup = NULL; + xa_lock(&ictx->groups); + while (true) { + igroup = __xa_cmpxchg(&ictx->groups, id, cur_igroup, new_igroup, + GFP_KERNEL); + if (xa_is_err(igroup)) { + xa_unlock(&ictx->groups); + iommufd_put_group(new_igroup); + return ERR_PTR(xa_err(igroup)); + } + + /* new_group was successfully installed */ + if (cur_igroup == igroup) { + xa_unlock(&ictx->groups); + return new_igroup; + } + + /* Check again if the current group is any good */ + if (iommufd_group_try_get(igroup, group)) { + xa_unlock(&ictx->groups); + iommufd_put_group(new_igroup); + return igroup; + } + cur_igroup = igroup; + } +} + void iommufd_device_destroy(struct iommufd_object *obj) { struct iommufd_device *idev = container_of(obj, struct iommufd_device, obj); iommu_device_release_dma_owner(idev->dev); - iommu_group_put(idev->group); + iommufd_put_group(idev->igroup); if (!iommufd_selftest_is_mock_dev(idev->dev)) iommufd_ctx_put(idev->ictx); } @@ -46,7 +154,7 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx, struct device *dev, u32 *id) { struct iommufd_device *idev; - struct iommu_group *group; + struct iommufd_group *igroup; int rc; /* @@ -56,9 +164,9 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx, if (!device_iommu_capable(dev, IOMMU_CAP_CACHE_COHERENCY)) return ERR_PTR(-EINVAL); - group = iommu_group_get(dev); - if (!group) - return ERR_PTR(-ENODEV); + igroup = iommufd_get_group(ictx, dev); + if (IS_ERR(igroup)) + return ERR_CAST(igroup); /* * For historical compat with VFIO the insecure interrupt path is @@ -67,7 +175,7 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx, * interrupt outside this iommufd context. */ if (!iommufd_selftest_is_mock_dev(dev) && - !iommu_group_has_isolated_msi(group)) { + !iommu_group_has_isolated_msi(igroup->group)) { if (!allow_unsafe_interrupts) { rc = -EPERM; goto out_group_put; @@ -97,8 +205,8 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx, device_iommu_capable(dev, IOMMU_CAP_ENFORCE_CACHE_COHERENCY); /* The calling driver is a user until iommufd_device_unbind() */ refcount_inc(&idev->obj.users); - /* group refcount moves into iommufd_device */ - idev->group = group; + /* igroup refcount moves into iommufd_device */ + idev->igroup = igroup; /* * If the caller fails after this success it must call @@ -113,7 +221,7 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx, out_release_owner: iommu_device_release_dma_owner(dev); out_group_put: - iommu_group_put(group); + iommufd_put_group(igroup); return ERR_PTR(rc); } EXPORT_SYMBOL_NS_GPL(iommufd_device_bind, IOMMUFD); @@ -170,14 +278,14 @@ static int iommufd_device_setup_msi(struct iommufd_device *idev, } static bool iommufd_hw_pagetable_has_group(struct iommufd_hw_pagetable *hwpt, - struct iommu_group *group) + struct iommufd_group *igroup) { struct iommufd_device *cur_dev; lockdep_assert_held(&hwpt->devices_lock); list_for_each_entry(cur_dev, &hwpt->devices, devices_item) - if (cur_dev->group == group) + if (cur_dev->igroup->group == igroup->group) return true; return false; } @@ -211,7 +319,8 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt, } rc = iopt_table_enforce_group_resv_regions(&hwpt->ioas->iopt, idev->dev, - idev->group, &sw_msi_start); + idev->igroup->group, + &sw_msi_start); if (rc) return rc; @@ -223,8 +332,8 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt, * FIXME: Hack around missing a device-centric iommu api, only attach to * the group once for the first device that is in the group. */ - if (!iommufd_hw_pagetable_has_group(hwpt, idev->group)) { - rc = iommu_attach_group(hwpt->domain, idev->group); + if (!iommufd_hw_pagetable_has_group(hwpt, idev->igroup)) { + rc = iommu_attach_group(hwpt->domain, idev->igroup->group); if (rc) goto err_unresv; } @@ -237,8 +346,8 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt, void iommufd_hw_pagetable_detach(struct iommufd_hw_pagetable *hwpt, struct iommufd_device *idev) { - if (!iommufd_hw_pagetable_has_group(hwpt, idev->group)) - iommu_detach_group(hwpt->domain, idev->group); + if (!iommufd_hw_pagetable_has_group(hwpt, idev->igroup)) + iommu_detach_group(hwpt->domain, idev->igroup->group); iopt_remove_reserved_iova(&hwpt->ioas->iopt, idev->dev); } diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index b38e67d1988bdb..f45615f19798e6 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -17,6 +17,7 @@ struct iommufd_device; struct iommufd_ctx { struct file *file; struct xarray objects; + struct xarray groups; u8 account_mode; /* Compatibility with VFIO no iommu */ @@ -262,6 +263,12 @@ void iommufd_hw_pagetable_detach(struct iommufd_hw_pagetable *hwpt, struct iommufd_device *idev); void iommufd_hw_pagetable_destroy(struct iommufd_object *obj); +struct iommufd_group { + struct kref ref; + struct iommufd_ctx *ictx; + struct iommu_group *group; +}; + /* * A iommufd_device object represents the binding relationship between a * consuming driver and the iommufd. These objects are created/destroyed by @@ -270,12 +277,12 @@ void iommufd_hw_pagetable_destroy(struct iommufd_object *obj); struct iommufd_device { struct iommufd_object obj; struct iommufd_ctx *ictx; + struct iommufd_group *igroup; struct iommufd_hw_pagetable *hwpt; /* Head at iommufd_hw_pagetable::devices */ struct list_head devices_item; /* always the physical device */ struct device *dev; - struct iommu_group *group; bool enforce_cache_coherency; }; diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c index 3fbe636c3d8a69..e5ed5dfa91a0b5 100644 --- a/drivers/iommu/iommufd/main.c +++ b/drivers/iommu/iommufd/main.c @@ -183,6 +183,7 @@ static int iommufd_fops_open(struct inode *inode, struct file *filp) } xa_init_flags(&ictx->objects, XA_FLAGS_ALLOC1 | XA_FLAGS_ACCOUNT); + xa_init(&ictx->groups); ictx->file = filp; filp->private_data = ictx; return 0; @@ -218,6 +219,7 @@ static int iommufd_fops_release(struct inode *inode, struct file *filp) if (WARN_ON(!destroyed)) break; } + WARN_ON(!xa_empty(&ictx->groups)); kfree(ictx); return 0; }