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Message-Id: <20220920081701.3453504-1-baolu.lu@linux.intel.com>
Date: Tue, 20 Sep 2022 16:17:01 +0800
From: Lu Baolu <baolu.lu@...ux.intel.com>
To: iommu@...ts.linux.dev
Cc: Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
Robin Murphy <robin.murphy@....com>,
Kevin Tian <kevin.tian@...el.com>,
Mika Westerberg <mika.westerberg@...ux.intel.com>,
George Hilliard <thirtythreeforty@...il.com>,
linux-kernel@...r.kernel.org, Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH 1/1] 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 <mika.westerberg@...ux.intel.com>
Reported-and-tested-by: George Hilliard <thirtythreeforty@...il.com>
Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
include/linux/dmar.h | 4 +---
drivers/iommu/intel/dmar.c | 7 -------
drivers/iommu/intel/iommu.c | 27 +++++++++++++++++++++++++--
3 files changed, 26 insertions(+), 12 deletions(-)
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())
diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 04f7991734a9..3528058d253e 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -2356,13 +2356,6 @@ 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 c20f3e060bac..5bab71a05830 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -3029,7 +3029,13 @@ 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;
}
@@ -3941,6 +3947,7 @@ 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");
@@ -3953,6 +3960,16 @@ 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();
@@ -3997,9 +4014,11 @@ 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
@@ -4017,10 +4036,12 @@ int __init intel_iommu_init(void)
"%s", iommu->name);
iommu_device_register(&iommu->iommu, &intel_iommu_ops, NULL);
}
+ up_read(&dmar_global_lock);
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");
@@ -4031,15 +4052,17 @@ 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;
}
--
2.34.1
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