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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: ni8bt4jA3BztpYyTlmDchqP5fNcaNhHHWYPbHpJ39+8hTAwZGQe4EbRVfv6dY8UN/yNPe/X4f8Alfk12iOw5KvVGi7sBHazHXI8jVnvSrM+UK6LguC5BNjl5vTCFsUTVBEjBNx62XnGkebxNuNMlPWfMNTuZ+zusUSVm1+HiY6Q9qwzy2IJw3tU6W5QjTKFQ1Lsaz+wrfGmhbyPA2XApy4p3vc+5UNwhY0h8C3H0DKleQ83u/mpx4ux6FaiaaDAiJvKTmf7e+7dH5T3sWTtjFuHmt9Ik2OClgYBwgisT0061q55SEnMnD9lSiXox/N98NWEYQhi6j7nkZ+Iy52JW/BS7tq1E02DcaXWbxHSpwtFepHW5NUhEPWe6ENDlQvLFPVWvfhFhWDzeJ61y5iPS8LPwOZ+5mAWS+2it3XgWElPcablsfSuGuT0/ZiUDDt8S X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Oct 2026 16:54:00.2578 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 92bd72f3-765d-4d6b-bbab-08df2f93e7b4 X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d;Ip=[4.158.2.129];Helo=[outbound-uk1.az.dlp.m.darktrace.com] X-MS-Exchange-CrossTenant-AuthSource: ZR1PEPF0000E6B4.eurprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: GV2PR08MB8073 On 10/5/26 20:30, Nicolin Chen wrote: > + /* > + * In a kdump case (set when CR0_SMMUEN=1 and !GERROR_SFM_ERR), retain > + * all the live CR0 fields, e.g. CR0_SMMUEN to avoid aborting in-flight > + * DMA and CR0_ATSCHK to carry on the ATS-check policy, while clearing > + * only the queue enable bits for this kernel to take over the queues. > + * > + * According to spec, updating STRTAB_BASE/CR1/CR2 when CR0_SMMUEN=1 is > + * CONSTRAINED UNPREDICTABLE. So, skip those register updates and rely > + * on the adopted stream table from the crashed kernel. > + */ > + if (smmu->options & ARM_SMMU_OPT_KDUMP_ADOPT) { > + dev_info(smmu->dev, > + "kdump: retaining SMMUEN for in-flight DMA\n"); > + enables = reg & ~(CR0_CMDQEN | CR0_EVTQEN | CR0_PRIQEN); > + goto reset_queues; nit: Is there some reason to separate the call to arm_smmu_write_reg_sync() under the ARM_SMMU_OPT_KDUMP_ADOPT check, below? > + } > + > + /* Clear CR0 and sync (disables SMMU and queue processing) */ > if (reg & CR0_SMMUEN) { > dev_warn(smmu->dev, "SMMU currently enabled! Resetting...\n"); > arm_smmu_update_gbpa(smmu, GBPA_ABORT, 0); > @@ -5181,12 +5199,41 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu) > /* Stream table */ > arm_smmu_write_strtab(smmu); > > +reset_queues: > + if (smmu->options & ARM_SMMU_OPT_KDUMP_ADOPT) { > + /*> + * Disable queues since arm_smmu_device_disable() was skipped. > + * CR0 fields are independent per spec, so the queue enable bits > + * can be cleared while retaining SMMUEN=1. > + */ > + ret = arm_smmu_write_reg_sync(smmu, enables, ARM_SMMU_CR0, > + ARM_SMMU_CR0ACK); > + if (ret) { > + dev_err(smmu->dev, "failed to disable queues\n"); > + return ret; > + } > + }