Commit 7ebb5f8e authored by Lu Baolu's avatar Lu Baolu Committed by Joerg Roedel
Browse files

Revert "iommu/vt-d: Fix possible recursive locking in intel_iommu_init()" 

This reverts commit 9cd4f143.

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: 9cd4f143 ("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 <mika.westerberg@linux.intel.com>
Cc: <stable@vger.kernel.org> # 5.19.x
Reported-and-tested-by: default avatarGeorge Hilliard <thirtythreeforty@gmail.com>
Signed-off-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20220920081701.3453504-1-baolu.lu@linux.intel.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 521a547c

drivers/iommu/intel/dmar.c

+0 −7
Original line number Diff line number Diff line
@@ -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 {

drivers/iommu/intel/iommu.c

+25 −2
Original line number Diff line number Diff line
@@ -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);



	intel_iommu_enabled = 1;

	dmar_register_bus_notifier();

	pr_info("Intel(R) Virtualization Technology for Directed I/O\n");



	intel_iommu_enabled = 1;



	return 0;



out_free_dmar:

	intel_iommu_free_dmars();

	up_write(&dmar_global_lock);

	return ret;

}

include/linux/dmar.h

+1 −3
Original line number Diff line number Diff line
@@ -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())