diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c index 4ae6df27ad5d..c9aca8841fa0 100644 --- a/drivers/iommu/dmar.c +++ b/drivers/iommu/dmar.c @@ -43,10 +43,19 @@ #include "irq_remapping.h" -/* No locks are needed as DMA remapping hardware unit - * list is constructed at boot time and hotplug of - * these units are not supported by the architecture. +/* + * Assumptions: + * 1) The hotplug framework guarentees that DMAR unit will be hot-added + * before IO devices managed by that unit. + * 2) The hotplug framework guarantees that DMAR unit will be hot-removed + * after IO devices managed by that unit. + * 3) Hotplug events are rare. + * + * Locking rules for DMA and interrupt remapping related global data structures: + * 1) Use dmar_global_lock in process context + * 2) Use RCU in interrupt context */ +DECLARE_RWSEM(dmar_global_lock); LIST_HEAD(dmar_drhd_units); struct acpi_table_header * __initdata dmar_tbl; @@ -565,6 +574,7 @@ int __init detect_intel_iommu(void) { int ret; + down_write(&dmar_global_lock); ret = dmar_table_detect(); if (ret) ret = check_zero_address(); @@ -582,6 +592,7 @@ int __init detect_intel_iommu(void) } early_acpi_os_unmap_memory((void __iomem *)dmar_tbl, dmar_tbl_size); dmar_tbl = NULL; + up_write(&dmar_global_lock); return ret ? 1 : -ENODEV; } @@ -1394,10 +1405,12 @@ static int __init dmar_free_unused_resources(void) if (irq_remapping_enabled || intel_iommu_enabled) return 0; + down_write(&dmar_global_lock); list_for_each_entry_safe(dmaru, dmaru_n, &dmar_drhd_units, list) { list_del(&dmaru->list); dmar_free_drhd(dmaru); } + up_write(&dmar_global_lock); return 0; } diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index bb98e37f2cf7..50d639a2df88 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -3637,11 +3637,13 @@ static int device_notifier(struct notifier_block *nb, if (!domain) return 0; + down_read(&dmar_global_lock); domain_remove_one_dev_info(domain, pdev); if (!(domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE) && !(domain->flags & DOMAIN_FLAG_STATIC_IDENTITY) && list_empty(&domain->devices)) domain_exit(domain); + up_read(&dmar_global_lock); return 0; } @@ -3659,6 +3661,13 @@ int __init intel_iommu_init(void) /* VT-d is required for a TXT/tboot launch, so enforce that */ force_on = tboot_force_iommu(); + if (iommu_init_mempool()) { + if (force_on) + panic("tboot: Failed to initialize iommu memory\n"); + return -ENOMEM; + } + + down_write(&dmar_global_lock); if (dmar_table_init()) { if (force_on) panic("tboot: Failed to initialize DMAR table\n"); @@ -3681,12 +3690,6 @@ int __init intel_iommu_init(void) if (no_iommu || dmar_disabled) goto out_free_dmar; - if (iommu_init_mempool()) { - if (force_on) - panic("tboot: Failed to initialize iommu memory\n"); - goto out_free_dmar; - } - if (list_empty(&dmar_rmrr_units)) printk(KERN_INFO "DMAR: No RMRR found\n"); @@ -3696,7 +3699,7 @@ int __init intel_iommu_init(void) if (dmar_init_reserved_ranges()) { if (force_on) panic("tboot: Failed to reserve iommu ranges\n"); - goto out_free_mempool; + goto out_free_reserved_range; } init_no_remapping_devices(); @@ -3708,6 +3711,7 @@ int __init intel_iommu_init(void) printk(KERN_ERR "IOMMU: dmar init failed\n"); goto out_free_reserved_range; } + up_write(&dmar_global_lock); printk(KERN_INFO "PCI-DMA: Intel(R) Virtualization Technology for Directed I/O\n"); @@ -3729,10 +3733,10 @@ int __init intel_iommu_init(void) out_free_reserved_range: put_iova_domain(&reserved_iova_list); -out_free_mempool: - iommu_exit_mempool(); out_free_dmar: intel_iommu_free_dmars(); + up_write(&dmar_global_lock); + iommu_exit_mempool(); return ret; } 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; + 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); - index = alloc_irte(iommu, irq, 1); - if (index < 0) - return -1; - - return 0; + return ret; } struct irq_remap_ops intel_irq_remap_ops = { diff --git a/include/linux/dmar.h b/include/linux/dmar.h index 4b77fd8fde76..8f06a0135a84 100644 --- a/include/linux/dmar.h +++ b/include/linux/dmar.h @@ -25,6 +25,7 @@ #include #include #include +#include struct acpi_dmar_header; @@ -48,6 +49,7 @@ struct dmar_drhd_unit { struct intel_iommu *iommu; }; +extern struct rw_semaphore dmar_global_lock; extern struct list_head dmar_drhd_units; #define for_each_drhd_unit(drhd) \