iommu/amd: Add locking to per-domain flush-queue

With locking we can safely access the flush-queues of other
cpus.

Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 9fafc3026865..9a06acc8cc9d 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -146,6 +146,7 @@ struct flush_queue_entry {
 struct flush_queue {
         struct flush_queue_entry *entries;
         unsigned head, tail;
+        spinlock_t lock;
 };
 
 /*
@@ -1801,6 +1802,8 @@ static int dma_ops_domain_alloc_flush_queue(struct dma_ops_domain *dom)
                         dma_ops_domain_free_flush_queue(dom);
                         return -ENOMEM;
                 }
+
+                spin_lock_init(&queue->lock);
         }
 
         return 0;
@@ -1808,6 +1811,8 @@ static int dma_ops_domain_alloc_flush_queue(struct dma_ops_domain *dom)
 
 static inline bool queue_ring_full(struct flush_queue *queue)
 {
+        assert_spin_locked(&queue->lock);
+
         return (((queue->tail + 1) % FLUSH_QUEUE_SIZE) == queue->head);
 }
 
@@ -1819,6 +1824,8 @@ static void queue_release(struct dma_ops_domain *dom,
 {
         unsigned i;
 
+        assert_spin_locked(&queue->lock);
+
         queue_ring_for_each(i, queue)
                 free_iova_fast(&dom->iovad,
                                queue->entries[i].iova_pfn,
@@ -1831,6 +1838,7 @@ static inline unsigned queue_ring_add(struct flush_queue *queue)
 {
         unsigned idx = queue->tail;
 
+        assert_spin_locked(&queue->lock);
         queue->tail = (idx + 1) % FLUSH_QUEUE_SIZE;
 
         return idx;
@@ -1840,12 +1848,14 @@ static void queue_add(struct dma_ops_domain *dom,
                       unsigned long address, unsigned long pages)
 {
         struct flush_queue *queue;
+        unsigned long flags;
         int idx;
 
         pages     = __roundup_pow_of_two(pages);
         address >>= PAGE_SHIFT;
 
         queue = get_cpu_ptr(dom->flush_queue);
+        spin_lock_irqsave(&queue->lock, flags);
 
         if (queue_ring_full(queue)) {
                 domain_flush_tlb(&dom->domain);
@@ -1858,6 +1868,7 @@ static void queue_add(struct dma_ops_domain *dom,
         queue->entries[idx].iova_pfn = address;
         queue->entries[idx].pages    = pages;
 
+        spin_unlock_irqrestore(&queue->lock, flags);
         put_cpu_ptr(dom->flush_queue);
 }