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Mon, 24 Feb 2025 13:31:12 -0800 Date: Mon, 24 Feb 2025 13:31:11 -0800 From: Nicolin Chen To: Pranjal Shrivastava CC: , , , , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH v7 12/14] iommu/arm-smmu-v3: Introduce struct arm_smmu_vmaster Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: X-NV-OnPremToCloud: AnonymousSubmission X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL02EPF0001A0FC:EE_|PH7PR12MB9256:EE_ X-MS-Office365-Filtering-Correlation-Id: 69e6464b-7925-41d5-dd63-08dd551a9a4f X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|82310400026|1800799024|7416014|376014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?NMM33Cb1mljFXv85AhXR/JU9o7eHy3+8+mxC8L48gBHyfln1AKy+6pH+2HAf?= =?us-ascii?Q?ggwQQOOTqRYTr+zE8wkUObDJaAPhdlggd3HHMiYgNF29tVqJIfI6ZnvB2CJF?= =?us-ascii?Q?SA2OHz46K7zfNn2W3WOjECfgpO3HbZqacs+atd/Q7FlVL1BzYgzDeryBFDJ3?= =?us-ascii?Q?FbbocTP5aVhXgqeOVwQkgFIbBE4hXEt1sFro/sB3/OJ5yb+W7VSIiWtD5EW7?= =?us-ascii?Q?70Lb7gUOFcv7eEYZ9IG+W2ujP520J2e/goMQRJ+THq0enJXt8zJcXx/g2LWN?= =?us-ascii?Q?xYRvgEmLwCXdigs/pbMFWPkQICQAYubUlZUMZ/mCS3ehdOgZYtRVt3GH8/Vk?= =?us-ascii?Q?TJ5kvDTmhbEuRx115XA33QLyy/B4eXbZYrMmyyGlUPzf5rTt12pqvd/INsGL?= =?us-ascii?Q?RMvyCu+rdKyibh1qEkJNtWHDZmDu8a2X1PQjxn5xDljD86zRUxoc3c84Vtco?= =?us-ascii?Q?7OCrWP6lOp1ch3sYN0enLFc6qg2LwnSnTGgjQzhH7HJ0tFYOg+gl3yLkm96v?= =?us-ascii?Q?3WbGxIBZjGJ/Z6yklE1rQ1FvsJyFnEQRITrfyiPVcvCXEcZnUTGOKjXhE8jA?= =?us-ascii?Q?tkecnRBoonvNSMhRQ40HxujJ/fzP0OrWNhWVXSwLE6hB2oB989xs6/TgXODA?= =?us-ascii?Q?56fOPrJbQXEx9eJWrr6PsJST811PPJ1kavZnqxaez1Fm8P2pTd98S1QqEFdy?= =?us-ascii?Q?Ownla04RFP1EU7IAK5Pqz5wyywA43e4sbrhvn/5zkretJddmGqhRk124Wkki?= =?us-ascii?Q?cPsqapUFFOuh63zmAKj4DpoXlN657Akjv7uhmeL4dtr3IC0znCo6fY2aVoej?= =?us-ascii?Q?qb1BjZjE/uGbWVoMlwan3GnLhzvwOeNaPQgXvi8Z95lk82HMVOIFPBsCwspt?= =?us-ascii?Q?cJdjop2iSakDIgL+V2uIk/+02qLE/YO7q4OQ9rqGEIQO6Tir7pkVtR8qUgPV?= =?us-ascii?Q?D+HfJTPjVPfS2DeGOfkKgMZ362z5us7SiJlHLWw6KQORGG2XWvtUfRX8Q8EI?= =?us-ascii?Q?8Apo6RxxBagCu65ozPDxNR1CpTHsc+mIPqzl/L1JQQC1If0pDzRRRqafDfqb?= =?us-ascii?Q?8DwD68AIafxXQHWloMJ/7Bp/TZemIfweS/cwV4RDqqHJqASuycuc1P4KSqXz?= =?us-ascii?Q?W0+prIzXtzzvJqJ4yR1Vn8ymUB2kMAu/I/d53tI0DywwRXq0KPV2yyup1ke+?= =?us-ascii?Q?B9W9vcIc0H1PsFh0AyDkuTknvbUhO0czxSOE+5mSAB8NjwcRzdNJtZ7u+GTx?= =?us-ascii?Q?5sawysJlhFKoZVZth8xF4xuEjAXhVFmBejS5Y5rTBOA0ezXLU4BI2iJFxev1?= =?us-ascii?Q?zcCuSbuViQNF/QGs+hJHYxaH6FJnC7yeK3Xh14QxcioNVc/0WN61/k/NxotA?= =?us-ascii?Q?k0GT9msAZa5WTAumdwSlkmQ4oP7rlBBvLJyQ+HMDDFcdZi7hNvhPbAbDPjra?= =?us-ascii?Q?v8Hqg9qMzEPlRfX6FyEpDeGFrwRX5sFuijNtLHhXkeZonpcZTZSz1ZFCKuYo?= =?us-ascii?Q?a5s7WtM08z6rKZI=3D?= X-Forefront-Antispam-Report: CIP:216.228.117.161;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc6edge2.nvidia.com;CAT:NONE;SFS:(13230040)(36860700013)(82310400026)(1800799024)(7416014)(376014);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Feb 2025 21:31:30.0883 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 69e6464b-7925-41d5-dd63-08dd551a9a4f X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.161];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BL02EPF0001A0FC.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB9256 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250224_133147_608136_B7FD3749 X-CRM114-Status: GOOD ( 21.58 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Feb 24, 2025 at 08:35:56PM +0000, Pranjal Shrivastava wrote: > oN sAt, Feb 22, 2025 at 07:54:09AM -0800, Nicolin Chen wrote: > > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c > > index 5aa2e7af58b4..364d8469a480 100644 > > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c > > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c > > @@ -85,6 +85,59 @@ static void arm_smmu_make_nested_domain_ste( > > } > > } > > > > +int arm_smmu_attach_prepare_vmaster(struct arm_smmu_attach_state *state, > > + struct iommu_domain *domain) > > +{ > > + struct arm_smmu_nested_domain *nested_domain; > > + struct arm_smmu_vmaster *vmaster; > > + unsigned long vsid; > > + int ret; > > + > > + iommu_group_mutex_assert(state->master->dev); > > + > > + if (domain->type != IOMMU_DOMAIN_NESTED) > > + return 0; > > + nested_domain = to_smmu_nested_domain(domain); > > + > > + /* Skip invalid vSTE */ > > + if (!(nested_domain->ste[0] & cpu_to_le64(STRTAB_STE_0_V))) > > + return 0; > > + > > + ret = iommufd_viommu_get_vdev_id(&nested_domain->vsmmu->core, > > + state->master->dev, &vsid); > > + if (ret) > > + return ret; > > + > > + vmaster = kzalloc(sizeof(*vmaster), GFP_KERNEL); > > + if (!vmaster) > > + return -ENOMEM; > > + vmaster->vsmmu = nested_domain->vsmmu; > > + vmaster->vsid = vsid; > > + state->vmaster = vmaster; > > + > > + return 0; > > +} > > + > > +void arm_smmu_attach_commit_vmaster(struct arm_smmu_attach_state *state) > > +{ > > + struct arm_smmu_master *master = state->master; > > + > > + mutex_lock(&master->smmu->streams_mutex); > > + if (state->vmaster != master->vmaster) { > > + kfree(master->vmaster); > > + master->vmaster = state->vmaster; > > + } > > Does this condition suggest that we might end up calling > `arm_smmu_attach_prepare_vmaster()` multiple times before __actually__ > commiting to a vmaster? No. prepare() and commit() are 1:1. How is it interpreted to have "multiple times"? > > + mutex_unlock(&master->smmu->streams_mutex); > > +} > > + > > +void arm_smmu_master_clear_vmaster(struct arm_smmu_master *master) > > +{ > > + mutex_lock(&master->smmu->streams_mutex); > > + kfree(master->vmaster); > > + master->vmaster = NULL; > > + mutex_unlock(&master->smmu->streams_mutex); > > +} > > + > > static int arm_smmu_attach_dev_nested(struct iommu_domain *domain, > > struct device *dev) > > { > > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > > index 358072b4e293..9e50bcee69d1 100644 > > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > > @@ -2803,6 +2803,7 @@ int arm_smmu_attach_prepare(struct arm_smmu_attach_state *state, > > struct arm_smmu_domain *smmu_domain = > > to_smmu_domain_devices(new_domain); > > unsigned long flags; > > + int ret; > > > > /* > > * arm_smmu_share_asid() must not see two domains pointing to the same > > @@ -2832,9 +2833,15 @@ int arm_smmu_attach_prepare(struct arm_smmu_attach_state *state, > > } > > > > if (smmu_domain) { > > + ret = arm_smmu_attach_prepare_vmaster(state, new_domain); > > IMO, this adds a little confusion for folks not using iommufd. > > I guess it'd be cleaner if we invoke this below within the: > `if (new_domain->type == IOMMU_DOMAIN_NESTED)` condition instead of > simply returning from the function if the new_domain->type isn't NESTED. But the arm_smmu_attach_commit_vmaster() still has to be unconditional as !NESTED domain should clean the vamster away.. Nicolin