1 files changed, 72 insertions, 36 deletions

diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index ef5f65dbafe9..9b174893f0f5 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -38,6 +38,17 @@ static struct ioapic_scope ir_ioapic[MAX_IO_APICS];
 static struct hpet_scope ir_hpet[MAX_HPET_TBS];
 static int ir_ioapic_num, ir_hpet_num;
 
+/*
+ * Lock ordering:
+ * ->dmar_global_lock
+ *      ->irq_2_ir_lock
+ *              ->qi->q_lock
+ *      ->iommu->register_lock
+ * Note:
+ * intel_irq_remap_ops.{supported,prepare,enable,disable,reenable} are called
+ * in single-threaded environment with interrupt disabled, so no need to tabke
+ * the dmar_global_lock.
+ */
 static DEFINE_RAW_SPINLOCK(irq_2_ir_lock);
 
 static int __init parse_ioapics_under_ir(void);
@@ -307,12 +318,14 @@ static int set_ioapic_sid(struct irte *irte, int apic)
         if (!irte)
                 return -1;
 
+        down_read(&dmar_global_lock);
         for (i = 0; i < MAX_IO_APICS; i++) {
                 if (ir_ioapic[i].id == apic) {
                         sid = (ir_ioapic[i].bus << 8) | ir_ioapic[i].devfn;
                         break;
                 }
         }
+        up_read(&dmar_global_lock);
 
         if (sid == 0) {
                 pr_warning("Failed to set source-id of IOAPIC (%d)\n", apic);
@@ -332,12 +345,14 @@ static int set_hpet_sid(struct irte *irte, u8 id)
         if (!irte)
                 return -1;
 
+        down_read(&dmar_global_lock);
         for (i = 0; i < MAX_HPET_TBS; i++) {
                 if (ir_hpet[i].id == id) {
                         sid = (ir_hpet[i].bus << 8) | ir_hpet[i].devfn;
                         break;
                 }
         }
+        up_read(&dmar_global_lock);
 
         if (sid == 0) {
                 pr_warning("Failed to set source-id of HPET block (%d)\n", id);
@@ -794,10 +809,16 @@ static int __init parse_ioapics_under_ir(void)
 
 static int __init ir_dev_scope_init(void)
 {
+        int ret;
+
         if (!irq_remapping_enabled)
                 return 0;
 
-        return dmar_dev_scope_init();
+        down_write(&dmar_global_lock);
+        ret = dmar_dev_scope_init();
+        up_write(&dmar_global_lock);
+
+        return ret;
 }
 rootfs_initcall(ir_dev_scope_init);
 
@@ -878,23 +899,27 @@ static int intel_setup_ioapic_entry(int irq,
                                     struct io_apic_irq_attr *attr)
 {
         int ioapic_id = mpc_ioapic_id(attr->ioapic);
-        struct intel_iommu *iommu = map_ioapic_to_ir(ioapic_id);
+        struct intel_iommu *iommu;
         struct IR_IO_APIC_route_entry *entry;
         struct irte irte;
         int index;
 
+        down_read(&dmar_global_lock);
+        iommu = map_ioapic_to_ir(ioapic_id);
         if (!iommu) {
                 pr_warn("No mapping iommu for ioapic %d\n", ioapic_id);
-                return -ENODEV;
-        }
-
-        entry = (struct IR_IO_APIC_route_entry *)route_entry;
-
-        index = alloc_irte(iommu, irq, 1);
-        if (index < 0) {
-                pr_warn("Failed to allocate IRTE for ioapic %d\n", ioapic_id);
-                return -ENOMEM;
+                index = -ENODEV;
+        } else {
+                index = alloc_irte(iommu, irq, 1);
+                if (index < 0) {
+                        pr_warn("Failed to allocate IRTE for ioapic %d\n",
+                                ioapic_id);
+                        index = -ENOMEM;
+                }
         }
+        up_read(&dmar_global_lock);
+        if (index < 0)
+                return index;
 
         prepare_irte(&irte, vector, destination);
 
@@ -913,6 +938,7 @@ static int intel_setup_ioapic_entry(int irq,
                 irte.avail, irte.vector, irte.dest_id,
                 irte.sid, irte.sq, irte.svt);
 
+        entry = (struct IR_IO_APIC_route_entry *)route_entry;
         memset(entry, 0, sizeof(*entry));
 
         entry->index2   = (index >> 15) & 0x1;
@@ -1043,20 +1069,23 @@ static int intel_msi_alloc_irq(struct pci_dev *dev, int irq, int nvec)
         struct intel_iommu *iommu;
         int index;
 
+        down_read(&dmar_global_lock);
         iommu = map_dev_to_ir(dev);
         if (!iommu) {
                 printk(KERN_ERR
                        "Unable to map PCI %s to iommu\n", pci_name(dev));
-                return -ENOENT;
+                index = -ENOENT;
+        } else {
+                index = alloc_irte(iommu, irq, nvec);
+                if (index < 0) {
+                        printk(KERN_ERR
+                               "Unable to allocate %d IRTE for PCI %s\n",
+                               nvec, pci_name(dev));
+                        index = -ENOSPC;
+                }
         }
+        up_read(&dmar_global_lock);
 
-        index = alloc_irte(iommu, irq, nvec);
-        if (index < 0) {
-                printk(KERN_ERR
-                       "Unable to allocate %d IRTE for PCI %s\n", nvec,
-                       pci_name(dev));
-                return -ENOSPC;
-        }
         return index;
 }
 
@@ -1064,33 +1093,40 @@ static int intel_msi_setup_irq(struct pci_dev *pdev, unsigned int irq,
                                int index, int sub_handle)
 {
         struct intel_iommu *iommu;
+        int ret = -ENOENT;
 
+        down_read(&dmar_global_lock);
         iommu = map_dev_to_ir(pdev);
-        if (!iommu)
-                return -ENOENT;
-        /*
-         * setup the mapping between the irq and the IRTE
-         * base index, the sub_handle pointing to the
-         * appropriate interrupt remap table entry.
-         */
-        set_irte_irq(irq, iommu, index, sub_handle);
+        if (iommu) {
+                /*
+                 * setup the mapping between the irq and the IRTE
+                 * base index, the sub_handle pointing to the
+                 * appropriate interrupt remap table entry.
+                 */
+                set_irte_irq(irq, iommu, index, sub_handle);
+                ret = 0;
+        }
+        up_read(&dmar_global_lock);
 
-        return 0;
+        return ret;
 }
 
 static int intel_setup_hpet_msi(unsigned int irq, unsigned int id)
 {
-        struct intel_iommu *iommu = map_hpet_to_ir(id);
+        int ret = -1;
+        struct intel_iommu *iommu;
         int index;
 
-        if (!iommu)
-                return -1;
-
-        index = alloc_irte(iommu, irq, 1);
-        if (index < 0)
-                return -1;
+        down_read(&dmar_global_lock);
+        iommu = map_hpet_to_ir(id);
+        if (iommu) {
+                index = alloc_irte(iommu, irq, 1);
+                if (index >= 0)
+                        ret = 0;
+        }
+        up_read(&dmar_global_lock);
 
-        return 0;
+        return ret;
 }
 
 struct irq_remap_ops intel_irq_remap_ops = {