History

iommu/vt-d: Don't queue_iova() if there is no flush queue

Intel VT-d driver was reworked to use common deferred flushing implementation. Previously there was one global per-cpu flush queue, afterwards - one per domain. Before deferring a flush, the queue should be allocated and initialized. Currently only domains with IOMMU_DOMAIN_DMA type initialize their flush queue. It's probably worth to init it for static or unmanaged domains too, but it may be arguable - I'm leaving it to iommu folks. Prevent queuing an iova flush if the domain doesn't have a queue. The defensive check seems to be worth to keep even if queue would be initialized for all kinds of domains. And is easy backportable. On 4.19.43 stable kernel it has a user-visible effect: previously for devices in si domain there were crashes, on sata devices: BUG: spinlock bad magic on CPU#6, swapper/0/1 lock: 0xffff88844f582008, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0 CPU: 6 PID: 1 Comm: swapper/0 Not tainted 4.19.43 #1 Call Trace: <IRQ> dump_stack+0x61/0x7e spin_bug+0x9d/0xa3 do_raw_spin_lock+0x22/0x8e _raw_spin_lock_irqsave+0x32/0x3a queue_iova+0x45/0x115 intel_unmap+0x107/0x113 intel_unmap_sg+0x6b/0x76 __ata_qc_complete+0x7f/0x103 ata_qc_complete+0x9b/0x26a ata_qc_complete_multiple+0xd0/0xe3 ahci_handle_port_interrupt+0x3ee/0x48a ahci_handle_port_intr+0x73/0xa9 ahci_single_level_irq_intr+0x40/0x60 __handle_irq_event_percpu+0x7f/0x19a handle_irq_event_percpu+0x32/0x72 handle_irq_event+0x38/0x56 handle_edge_irq+0x102/0x121 handle_irq+0x147/0x15c do_IRQ+0x66/0xf2 common_interrupt+0xf/0xf RIP: 0010:__do_softirq+0x8c/0x2df The same for usb devices that use ehci-pci: BUG: spinlock bad magic on CPU#0, swapper/0/1 lock: 0xffff88844f402008, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.43 #4 Call Trace: <IRQ> dump_stack+0x61/0x7e spin_bug+0x9d/0xa3 do_raw_spin_lock+0x22/0x8e _raw_spin_lock_irqsave+0x32/0x3a queue_iova+0x77/0x145 intel_unmap+0x107/0x113 intel_unmap_page+0xe/0x10 usb_hcd_unmap_urb_setup_for_dma+0x53/0x9d usb_hcd_unmap_urb_for_dma+0x17/0x100 unmap_urb_for_dma+0x22/0x24 __usb_hcd_giveback_urb+0x51/0xc3 usb_giveback_urb_bh+0x97/0xde tasklet_action_common.isra.4+0x5f/0xa1 tasklet_action+0x2d/0x30 __do_softirq+0x138/0x2df irq_exit+0x7d/0x8b smp_apic_timer_interrupt+0x10f/0x151 apic_timer_interrupt+0xf/0x20 </IRQ> RIP: 0010:_raw_spin_unlock_irqrestore+0x17/0x39

Dmitry Safonov committed 7 years ago

Commit effa4671 parent 55752943 files · +22 −5Browse files

Unified · Split

3 files
  1. drivers/iommu/intel-iommu.c +2 −1
  2. drivers/iommu/iova.c +14 −4
  3. include/linux/iova.h +6 −0
drivers/iommu/intel-iommu.c+2−1
@@ -3561,7 +3561,8 @@ static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size) · 3560 unmodified lines
3561 3561
3562 freelist = domain_unmap(domain, start_pfn, last_pfn);3562 freelist = domain_unmap(domain, start_pfn, last_pfn);
3563 3563
3564 if (intel_iommu_strict || (pdev && pdev->untrusted)) {3564 if (intel_iommu_strict || (pdev && pdev->untrusted) ||
3565 !has_iova_flush_queue(&domain->iovad)) {
3565 iommu_flush_iotlb_psi(iommu, domain, start_pfn,3566 iommu_flush_iotlb_psi(iommu, domain, start_pfn,
3566 nrpages, !freelist, 0);3567 nrpages, !freelist, 0);
3567 /* free iova */3568 /* free iova */
drivers/iommu/iova.c+14−4
@@ -54,9 +54,14 @@ init_iova_domain(struct iova_domain *iovad, unsigned long granule, · 53 unmodified lines
54}54}
55EXPORT_SYMBOL_GPL(init_iova_domain);55EXPORT_SYMBOL_GPL(init_iova_domain);
56 56
57bool has_iova_flush_queue(struct iova_domain *iovad)
58{
59 return !!iovad->fq;
60}
61
57static void free_iova_flush_queue(struct iova_domain *iovad)62static void free_iova_flush_queue(struct iova_domain *iovad)
58{63{
59 if (!iovad->fq)64 if (!has_iova_flush_queue(iovad))
60 return;65 return;
61 66
62 if (timer_pending(&iovad->fq_timer))67 if (timer_pending(&iovad->fq_timer))
@@ -74,13 +79,14 @@ static void free_iova_flush_queue(struct iova_domain *iovad) · 11 unmodified lines
74int init_iova_flush_queue(struct iova_domain *iovad,79int init_iova_flush_queue(struct iova_domain *iovad,
75 iova_flush_cb flush_cb, iova_entry_dtor entry_dtor)80 iova_flush_cb flush_cb, iova_entry_dtor entry_dtor)
76{81{
82 struct iova_fq __percpu *queue;
77 int cpu;83 int cpu;
78 84
79 atomic64_set(&iovad->fq_flush_start_cnt, 0);85 atomic64_set(&iovad->fq_flush_start_cnt, 0);
80 atomic64_set(&iovad->fq_flush_finish_cnt, 0);86 atomic64_set(&iovad->fq_flush_finish_cnt, 0);
81 87
82 iovad->fq = alloc_percpu(struct iova_fq);88 queue = alloc_percpu(struct iova_fq);
83 if (!iovad->fq)89 if (!queue)
84 return -ENOMEM;90 return -ENOMEM;
85 91
86 iovad->flush_cb = flush_cb;92 iovad->flush_cb = flush_cb;
@@ -89,13 +95,17 @@ int init_iova_flush_queue(struct iova_domain *iovad, · 2 unmodified lines
89 for_each_possible_cpu(cpu) {95 for_each_possible_cpu(cpu) {
90 struct iova_fq *fq;96 struct iova_fq *fq;
91 97
92 fq = per_cpu_ptr(iovad->fq, cpu);98 fq = per_cpu_ptr(queue, cpu);
93 fq->head = 0;99 fq->head = 0;
94 fq->tail = 0;100 fq->tail = 0;
95 101
96 spin_lock_init(&fq->lock);102 spin_lock_init(&fq->lock);
97 }103 }
98 104
105 smp_wmb();
106
107 iovad->fq = queue;
108
99 timer_setup(&iovad->fq_timer, fq_flush_timeout, 0);109 timer_setup(&iovad->fq_timer, fq_flush_timeout, 0);
100 atomic_set(&iovad->fq_timer_on, 0);110 atomic_set(&iovad->fq_timer_on, 0);
101 111
include/linux/iova.h+6−0
@@ -155,6 +155,7 @@ struct iova *reserve_iova(struct iova_domain *iovad, unsigned long pfn_lo, · 154 unmodified lines
155void copy_reserved_iova(struct iova_domain *from, struct iova_domain *to);155void copy_reserved_iova(struct iova_domain *from, struct iova_domain *to);
156void init_iova_domain(struct iova_domain *iovad, unsigned long granule,156void init_iova_domain(struct iova_domain *iovad, unsigned long granule,
157 unsigned long start_pfn);157 unsigned long start_pfn);
158bool has_iova_flush_queue(struct iova_domain *iovad);
158int init_iova_flush_queue(struct iova_domain *iovad,159int init_iova_flush_queue(struct iova_domain *iovad,
159 iova_flush_cb flush_cb, iova_entry_dtor entry_dtor);160 iova_flush_cb flush_cb, iova_entry_dtor entry_dtor);
160struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn);161struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn);
@@ -235,6 +236,11 @@ static inline void init_iova_domain(struct iova_domain *iovad, · 74 unmodified lines
235{236{
236}237}
237 238
239bool has_iova_flush_queue(struct iova_domain *iovad)
240{
241 return false;
242}
243
238static inline int init_iova_flush_queue(struct iova_domain *iovad,244static inline int init_iova_flush_queue(struct iova_domain *iovad,
239 iova_flush_cb flush_cb,245 iova_flush_cb flush_cb,
240 iova_entry_dtor entry_dtor)246 iova_entry_dtor entry_dtor)