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Received-SPF: Pass (protection.outlook.com: domain of amd.com designates 165.204.84.17 as permitted sender) receiver=protection.outlook.com; client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; Received: from SATLEXMB04.amd.com (165.204.84.17) by BN8NAM11FT017.mail.protection.outlook.com (10.13.177.93) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.5123.19 via Frontend Transport; Mon, 4 Apr 2022 16:47:30 +0000 Received: from AUS-LX-MLIMONCI.amd.com (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 4 Apr 2022 11:47:26 -0500 From: Mario Limonciello To: Joerg Roedel , Will Deacon CC: Christoph Hellwig , Marek Szyprowski , Robin Murphy , "open list:IOMMU DRIVERS" , Suthikulpanit Suravee , Hegde Vasant , "open list" , Mario Limonciello Subject: [PATCH 1/2] swiotlb: Check that slabs have been allocated when requested Date: Mon, 4 Apr 2022 11:47:06 -0500 Message-ID: <20220404164707.1128-2-mario.limonciello@amd.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220404164707.1128-1-mario.limonciello@amd.com> References: <20220404164707.1128-1-mario.limonciello@amd.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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-Office365-Filtering-Correlation-Id: 6ee731ba-e78f-469c-6b0b-08da165acf7b X-MS-TrafficTypeDiagnostic: CH2PR12MB4280:EE_ X-Microsoft-Antispam-PRVS: X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Apr 2022 16:47:30.9561 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 6ee731ba-e78f-469c-6b0b-08da165acf7b 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: BN8NAM11FT017.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR12MB4280 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" If the IOMMU is in use and an untrusted device is connected to an external facing port but the address requested isn't page aligned will cause the kernel to attempt to use bounce buffers. If the bounce buffers have not been allocated however, this leads to messages like this: swiotlb buffer is full (sz: 4096 bytes), total 0 (slots), used 0 (slots) Clarify the error message because the buffer isn't full, it doesn't exist! Signed-off-by: Mario Limonciello --- kernel/dma/swiotlb.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 73a41cec9e38..d2a20cedf0d2 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -591,6 +591,11 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev,= phys_addr_t orig_addr, if (!mem) panic("Can not allocate SWIOTLB buffer earlier and can't now provide you= with the DMA bounce buffer"); =20 + if (!mem->nslabs) { + dev_warn_once(dev, "No slabs have been configured, unable to use SWIOTLB= buffer"); + return (phys_addr_t)DMA_MAPPING_ERROR; + } + if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) pr_warn_once("Memory encryption is active and system is using DMA bounce= buffers\n"); =20 --=20 2.34.1 From nobody Fri Jun 19 11:03:35 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6CA8C35276 for ; 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Received-SPF: Pass (protection.outlook.com: domain of amd.com designates 165.204.84.17 as permitted sender) receiver=protection.outlook.com; client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; Received: from SATLEXMB04.amd.com (165.204.84.17) by BN8NAM11FT017.mail.protection.outlook.com (10.13.177.93) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.5123.19 via Frontend Transport; Mon, 4 Apr 2022 16:47:33 +0000 Received: from AUS-LX-MLIMONCI.amd.com (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 4 Apr 2022 11:47:27 -0500 From: Mario Limonciello To: Joerg Roedel , Will Deacon CC: Christoph Hellwig , Marek Szyprowski , Robin Murphy , "open list:IOMMU DRIVERS" , Suthikulpanit Suravee , Hegde Vasant , "open list" , Mario Limonciello Subject: [PATCH 2/2] iommu: Don't use swiotlb unless it's active Date: Mon, 4 Apr 2022 11:47:07 -0500 Message-ID: <20220404164707.1128-3-mario.limonciello@amd.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220404164707.1128-1-mario.limonciello@amd.com> References: <20220404164707.1128-1-mario.limonciello@amd.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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-Office365-Filtering-Correlation-Id: c7ace693-d299-4422-190c-08da165ad0d5 X-MS-TrafficTypeDiagnostic: CH2PR12MB4230:EE_ X-Microsoft-Antispam-PRVS: X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Apr 2022 16:47:33.2215 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: c7ace693-d299-4422-190c-08da165ad0d5 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: BN8NAM11FT017.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR12MB4230 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The helper function `dev_use_swiotlb` is used for various decision making points for how to handle DMA mapping requests. If the kernel doesn't have any memory allocated for swiotlb to use, then an untrusted device being connected to the system may fail to initialize when a request is made. To avoid this situation, don't mark the use of swiotlb when it has not been set up. Signed-off-by: Mario Limonciello --- drivers/iommu/dma-iommu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 09f6e1c0f9c0..92ca136c8a12 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -504,7 +504,8 @@ static bool dev_is_untrusted(struct device *dev) =20 static bool dev_use_swiotlb(struct device *dev) { - return IS_ENABLED(CONFIG_SWIOTLB) && dev_is_untrusted(dev); + return IS_ENABLED(CONFIG_SWIOTLB) && dev_is_untrusted(dev) \ + && is_swiotlb_active(dev); } =20 /** --=20 2.34.1