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Wed, 14 Sep 2022 09:44:57 -0500 From: Vasant Hegde To: , CC: , , Vasant Hegde Subject: [RFC PATCH] iommu: Handle domain allocation failure gracefully Date: Wed, 14 Sep 2022 14:44:24 +0000 Message-ID: <20220914144424.7356-1-vasant.hegde@amd.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.180.168.240] X-ClientProxiedBy: SATLEXMB03.amd.com (10.181.40.144) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN8NAM11FT094:EE_|SA0PR12MB4416:EE_ X-MS-Office365-Filtering-Correlation-Id: fab17c1d-d69c-4fb4-b1be-08da965fbbe8 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:SATLEXMB04.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230022)(4636009)(136003)(396003)(346002)(39860400002)(376002)(451199015)(46966006)(36840700001)(40470700004)(2616005)(82740400003)(40460700003)(8676002)(40480700001)(2906002)(36756003)(356005)(47076005)(82310400005)(54906003)(186003)(86362001)(1076003)(8936002)(110136005)(83380400001)(336012)(7696005)(5660300002)(426003)(81166007)(16526019)(6666004)(36860700001)(44832011)(70586007)(316002)(70206006)(41300700001)(26005)(478600001)(4326008)(36900700001);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Sep 2022 14:45:14.4370 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: fab17c1d-d69c-4fb4-b1be-08da965fbbe8 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BN8NAM11FT094.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA0PR12MB4416 Current code does not validate domain allocation failures. This will result in random failure at later stage. Hence handle domain allocation failures. Signed-off-by: Vasant Hegde --- Hi Joerg, With current code whenever amd driver failes to allocate domain we hit failure at late stage and it became difficult to debug. Hence I thought of adding this fix. I see that in commit 6e1aa2049154 you have intentionally didn't check the return value. Looking into drivers/iommu/* it looks like all drivers has domain_alloc() callback handler. But some drivers (like msm - msm_iommu_domain_alloc()) allocates default domain for certain type only. Hence I'm not sure whether its ok to handle domain allocation failures or not. Hence I have marked this patch as RFC. Let me know whether this patch is fine -OR- is there any other way we can handle domain allocation failures? -Vasant drivers/iommu/iommu.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 780fb7071577..e8a1e7fbffb9 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -289,18 +289,21 @@ int iommu_probe_device(struct device *dev) /* * Try to allocate a default domain - needs support from the - * IOMMU driver. There are still some drivers which don't - * support default domains, so the return value is not yet - * checked. + * IOMMU driver. */ mutex_lock(&group->mutex); - iommu_alloc_default_domain(group, dev); + ret = iommu_alloc_default_domain(group, dev); + if (ret) { + mutex_unlock(&group->mutex); + iommu_group_put(group); + goto err_release; + } /* * If device joined an existing group which has been claimed, don't * attach the default domain. */ - if (group->default_domain && !group->owner) { + if (!group->owner) { ret = __iommu_attach_device(group->default_domain, dev); if (ret) { mutex_unlock(&group->mutex); @@ -1665,7 +1668,7 @@ static int probe_get_default_domain_type(struct device *dev, void *data) return 0; } -static void probe_alloc_default_domain(struct bus_type *bus, +static int probe_alloc_default_domain(struct bus_type *bus, struct iommu_group *group) { struct __group_domain_type gtype; @@ -1679,7 +1682,7 @@ static void probe_alloc_default_domain(struct bus_type *bus, if (!gtype.type) gtype.type = iommu_def_domain_type; - iommu_group_alloc_default_domain(bus, group, gtype.type); + return iommu_group_alloc_default_domain(bus, group, gtype.type); } @@ -1753,11 +1756,10 @@ int bus_iommu_probe(struct bus_type *bus) mutex_lock(&group->mutex); /* Try to allocate default domain */ - probe_alloc_default_domain(bus, group); - - if (!group->default_domain) { + ret = probe_alloc_default_domain(bus, group); + if (ret) { mutex_unlock(&group->mutex); - continue; + break; } iommu_group_create_direct_mappings(group); -- 2.31.1