From 7ebb5f8e001037efbdf18afabbbebf71bd98825e Mon Sep 17 00:00:00 2001 From: Lu Baolu Date: Wed, 21 Sep 2022 10:40:53 +0800 Subject: [PATCH] Revert "iommu/vt-d: Fix possible recursive locking in intel_iommu_init()" This reverts commit 9cd4f1434479f1ac25c440c421fbf52069079914. Some issues were reported on the original commit. Some thunderbolt devices don't work anymore due to the following DMA fault. DMAR: DRHD: handling fault status reg 2 DMAR: [INTR-REMAP] Request device [09:00.0] fault index 0x8080 [fault reason 0x25] Blocked a compatibility format interrupt request Bring it back for now to avoid functional regression. Fixes: 9cd4f1434479f ("iommu/vt-d: Fix possible recursive locking in intel_iommu_init()") Link: https://lore.kernel.org/linux-iommu/485A6EA5-6D58-42EA-B298-8571E97422DE@getmailspring.com/ Link: https://bugzilla.kernel.org/show_bug.cgi?id=216497 Cc: Mika Westerberg Cc: # 5.19.x Reported-and-tested-by: George Hilliard Signed-off-by: Lu Baolu Link: https://lore.kernel.org/r/20220920081701.3453504-1-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel --- drivers/iommu/intel/dmar.c | 7 ------- drivers/iommu/intel/iommu.c | 27 +++++++++++++++++++++++++-- include/linux/dmar.h | 4 +--- 3 files changed, 26 insertions(+), 12 deletions(-) diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c index 497c912ad9e1..5a8f780e7ffd 100644 --- a/drivers/iommu/intel/dmar.c +++ b/drivers/iommu/intel/dmar.c @@ -2349,13 +2349,6 @@ static int dmar_device_hotplug(acpi_handle handle, bool insert) if (!dmar_in_use()) return 0; - /* - * It's unlikely that any I/O board is hot added before the IOMMU - * subsystem is initialized. - */ - if (IS_ENABLED(CONFIG_INTEL_IOMMU) && !intel_iommu_enabled) - return -EOPNOTSUPP; - if (dmar_detect_dsm(handle, DMAR_DSM_FUNC_DRHD)) { tmp = handle; } else { diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 1f2cd43cf9bc..64d30895a4c8 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -3019,7 +3019,13 @@ static int __init init_dmars(void) #ifdef CONFIG_INTEL_IOMMU_SVM if (pasid_supported(iommu) && ecap_prs(iommu->ecap)) { + /* + * Call dmar_alloc_hwirq() with dmar_global_lock held, + * could cause possible lock race condition. + */ + up_write(&dmar_global_lock); ret = intel_svm_enable_prq(iommu); + down_write(&dmar_global_lock); if (ret) goto free_iommu; } @@ -3932,6 +3938,7 @@ int __init intel_iommu_init(void) force_on = (!intel_iommu_tboot_noforce && tboot_force_iommu()) || platform_optin_force_iommu(); + down_write(&dmar_global_lock); if (dmar_table_init()) { if (force_on) panic("tboot: Failed to initialize DMAR table\n"); @@ -3944,6 +3951,16 @@ int __init intel_iommu_init(void) goto out_free_dmar; } + up_write(&dmar_global_lock); + + /* + * The bus notifier takes the dmar_global_lock, so lockdep will + * complain later when we register it under the lock. + */ + dmar_register_bus_notifier(); + + down_write(&dmar_global_lock); + if (!no_iommu) intel_iommu_debugfs_init(); @@ -3988,9 +4005,11 @@ int __init intel_iommu_init(void) pr_err("Initialization failed\n"); goto out_free_dmar; } + up_write(&dmar_global_lock); init_iommu_pm_ops(); + down_read(&dmar_global_lock); for_each_active_iommu(iommu, drhd) { /* * The flush queue implementation does not perform @@ -4008,11 +4027,13 @@ int __init intel_iommu_init(void) "%s", iommu->name); iommu_device_register(&iommu->iommu, &intel_iommu_ops, NULL); } + up_read(&dmar_global_lock); bus_set_iommu(&pci_bus_type, &intel_iommu_ops); if (si_domain && !hw_pass_through) register_memory_notifier(&intel_iommu_memory_nb); + down_read(&dmar_global_lock); if (probe_acpi_namespace_devices()) pr_warn("ACPI name space devices didn't probe correctly\n"); @@ -4023,15 +4044,17 @@ int __init intel_iommu_init(void) iommu_disable_protect_mem_regions(iommu); } + up_read(&dmar_global_lock); + + pr_info("Intel(R) Virtualization Technology for Directed I/O\n"); intel_iommu_enabled = 1; - dmar_register_bus_notifier(); - pr_info("Intel(R) Virtualization Technology for Directed I/O\n"); return 0; out_free_dmar: intel_iommu_free_dmars(); + up_write(&dmar_global_lock); return ret; } diff --git a/include/linux/dmar.h b/include/linux/dmar.h index 8917a32173c4..d81a51978d01 100644 --- a/include/linux/dmar.h +++ b/include/linux/dmar.h @@ -65,7 +65,6 @@ struct dmar_pci_notify_info { extern struct rw_semaphore dmar_global_lock; extern struct list_head dmar_drhd_units; -extern int intel_iommu_enabled; #define for_each_drhd_unit(drhd) \ list_for_each_entry_rcu(drhd, &dmar_drhd_units, list, \ @@ -89,8 +88,7 @@ extern int intel_iommu_enabled; static inline bool dmar_rcu_check(void) { return rwsem_is_locked(&dmar_global_lock) || - system_state == SYSTEM_BOOTING || - (IS_ENABLED(CONFIG_INTEL_IOMMU) && !intel_iommu_enabled); + system_state == SYSTEM_BOOTING; } #define dmar_rcu_dereference(p) rcu_dereference_check((p), dmar_rcu_check())