iommu/vt-d: Introduce a rwsem to protect global data structures

[deliverable/linux.git] / drivers / iommu / intel_irq_remapping.c

diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index ef5f65dbafe92d81c9d6fefa9990b76662347c50..9b174893f0f5bd7c19810dc2840b3fef2728e9ad 100644 (file)
--- 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 = {