From 2b0d3902354418673ca24e319dcbf1119df5a690 Mon Sep 17 00:00:00 2001
From: Scott Wood <swood@redhat.com>
Date: Sun, 21 Jan 2018 03:28:54 -0600
Subject: [PATCH 005/518] iommu/amd: Use raw locks on atomic context paths

Upstream commit 27790398c2aed917828dc3c6f81240d57f1584c9

Several functions in this driver are called from atomic context,
and thus raw locks must be used in order to be safe on PREEMPT_RT.

This includes paths that must wait for command completion, which is
a potential PREEMPT_RT latency concern but not easily avoidable.

Signed-off-by: Scott Wood <swood@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/iommu/amd_iommu.c       | 30 +++++++++++++++---------------
 drivers/iommu/amd_iommu_init.c  |  2 +-
 drivers/iommu/amd_iommu_types.h |  4 ++--
 3 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 8195ff219b48c..7a54e9e9a1d6a 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1073,9 +1073,9 @@ static int iommu_queue_command_sync(struct amd_iommu *iommu,
 	unsigned long flags;
 	int ret;
 
-	spin_lock_irqsave(&iommu->lock, flags);
+	raw_spin_lock_irqsave(&iommu->lock, flags);
 	ret = __iommu_queue_command_sync(iommu, cmd, sync);
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	raw_spin_unlock_irqrestore(&iommu->lock, flags);
 
 	return ret;
 }
@@ -1101,7 +1101,7 @@ static int iommu_completion_wait(struct amd_iommu *iommu)
 
 	build_completion_wait(&cmd, (u64)&iommu->cmd_sem);
 
-	spin_lock_irqsave(&iommu->lock, flags);
+	raw_spin_lock_irqsave(&iommu->lock, flags);
 
 	iommu->cmd_sem = 0;
 
@@ -1112,7 +1112,7 @@ static int iommu_completion_wait(struct amd_iommu *iommu)
 	ret = wait_on_sem(&iommu->cmd_sem);
 
 out_unlock:
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	raw_spin_unlock_irqrestore(&iommu->lock, flags);
 
 	return ret;
 }
@@ -3688,7 +3688,7 @@ static struct irq_remap_table *get_irq_table(u16 devid, bool ioapic)
 		goto out_unlock;
 
 	/* Initialize table spin-lock */
-	spin_lock_init(&table->lock);
+	raw_spin_lock_init(&table->lock);
 
 	if (ioapic)
 		/* Keep the first 32 indexes free for IOAPIC interrupts */
@@ -3747,7 +3747,7 @@ static int alloc_irq_index(u16 devid, int count)
 	if (!table)
 		return -ENODEV;
 
-	spin_lock_irqsave(&table->lock, flags);
+	raw_spin_lock_irqsave(&table->lock, flags);
 
 	/* Scan table for free entries */
 	for (c = 0, index = table->min_index;
@@ -3770,7 +3770,7 @@ static int alloc_irq_index(u16 devid, int count)
 	index = -ENOSPC;
 
 out:
-	spin_unlock_irqrestore(&table->lock, flags);
+	raw_spin_unlock_irqrestore(&table->lock, flags);
 
 	return index;
 }
@@ -3791,7 +3791,7 @@ static int modify_irte_ga(u16 devid, int index, struct irte_ga *irte,
 	if (!table)
 		return -ENOMEM;
 
-	spin_lock_irqsave(&table->lock, flags);
+	raw_spin_lock_irqsave(&table->lock, flags);
 
 	entry = (struct irte_ga *)table->table;
 	entry = &entry[index];
@@ -3802,7 +3802,7 @@ static int modify_irte_ga(u16 devid, int index, struct irte_ga *irte,
 	if (data)
 		data->ref = entry;
 
-	spin_unlock_irqrestore(&table->lock, flags);
+	raw_spin_unlock_irqrestore(&table->lock, flags);
 
 	iommu_flush_irt(iommu, devid);
 	iommu_completion_wait(iommu);
@@ -3824,9 +3824,9 @@ static int modify_irte(u16 devid, int index, union irte *irte)
 	if (!table)
 		return -ENOMEM;
 
-	spin_lock_irqsave(&table->lock, flags);
+	raw_spin_lock_irqsave(&table->lock, flags);
 	table->table[index] = irte->val;
-	spin_unlock_irqrestore(&table->lock, flags);
+	raw_spin_unlock_irqrestore(&table->lock, flags);
 
 	iommu_flush_irt(iommu, devid);
 	iommu_completion_wait(iommu);
@@ -3848,9 +3848,9 @@ static void free_irte(u16 devid, int index)
 	if (!table)
 		return;
 
-	spin_lock_irqsave(&table->lock, flags);
+	raw_spin_lock_irqsave(&table->lock, flags);
 	iommu->irte_ops->clear_allocated(table, index);
-	spin_unlock_irqrestore(&table->lock, flags);
+	raw_spin_unlock_irqrestore(&table->lock, flags);
 
 	iommu_flush_irt(iommu, devid);
 	iommu_completion_wait(iommu);
@@ -4430,7 +4430,7 @@ int amd_iommu_update_ga(int cpu, bool is_run, void *data)
 	if (!irt)
 		return -ENODEV;
 
-	spin_lock_irqsave(&irt->lock, flags);
+	raw_spin_lock_irqsave(&irt->lock, flags);
 
 	if (ref->lo.fields_vapic.guest_mode) {
 		if (cpu >= 0)
@@ -4439,7 +4439,7 @@ int amd_iommu_update_ga(int cpu, bool is_run, void *data)
 		barrier();
 	}
 
-	spin_unlock_irqrestore(&irt->lock, flags);
+	raw_spin_unlock_irqrestore(&irt->lock, flags);
 
 	iommu_flush_irt(iommu, devid);
 	iommu_completion_wait(iommu);
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 8b7702553fa41..39fdb8eb257a5 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -1481,7 +1481,7 @@ static int __init init_iommu_one(struct amd_iommu *iommu, struct ivhd_header *h)
 {
 	int ret;
 
-	spin_lock_init(&iommu->lock);
+	raw_spin_lock_init(&iommu->lock);
 
 	/* Add IOMMU to internal data structures */
 	list_add_tail(&iommu->list, &amd_iommu_list);
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index 3caf3b1e8d67f..568510fab5be5 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -412,7 +412,7 @@ extern bool amd_iommu_iotlb_sup;
 #define IRQ_TABLE_ALIGNMENT	128
 
 struct irq_remap_table {
-	spinlock_t lock;
+	raw_spinlock_t lock;
 	unsigned min_index;
 	u32 *table;
 };
@@ -494,7 +494,7 @@ struct amd_iommu {
 	int index;
 
 	/* locks the accesses to the hardware */
-	spinlock_t lock;
+	raw_spinlock_t lock;
 
 	/* Pointer to PCI device of this IOMMU */
 	struct pci_dev *dev;
-- 
2.41.0

