iommu/iova: Add flush timer

Add a timer to flush entries from the Flush-Queues every
10ms. This makes sure that no stale TLB entries remain for
too long after an IOVA has been unmapped.

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

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 749d395..33edfa7 100644 (file)
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -33,6 +33,7 @@ static unsigned long iova_rcache_get(struct iova_domain *iovad,
 static void init_iova_rcaches(struct iova_domain *iovad);
 static void free_iova_rcaches(struct iova_domain *iovad);
 static void fq_destroy_all_entries(struct iova_domain *iovad);
+static void fq_flush_timeout(unsigned long data);
 
 void
 init_iova_domain(struct iova_domain *iovad, unsigned long granule,
@@ -62,7 +63,11 @@ static void free_iova_flush_queue(struct iova_domain *iovad)
        if (!iovad->fq)
                return;
 
+       if (timer_pending(&iovad->fq_timer))
+               del_timer(&iovad->fq_timer);
+
        fq_destroy_all_entries(iovad);
+
        free_percpu(iovad->fq);
 
        iovad->fq         = NULL;
@@ -95,6 +100,9 @@ int init_iova_flush_queue(struct iova_domain *iovad,
                spin_lock_init(&fq->lock);
        }
 
+       setup_timer(&iovad->fq_timer, fq_flush_timeout, (unsigned long)iovad);
+       atomic_set(&iovad->fq_timer_on, 0);
+
        return 0;
 }
 EXPORT_SYMBOL_GPL(init_iova_flush_queue);
@@ -539,6 +547,25 @@ static void fq_destroy_all_entries(struct iova_domain *iovad)
        }
 }
 
+static void fq_flush_timeout(unsigned long data)
+{
+       struct iova_domain *iovad = (struct iova_domain *)data;
+       int cpu;
+
+       atomic_set(&iovad->fq_timer_on, 0);
+       iova_domain_flush(iovad);
+
+       for_each_possible_cpu(cpu) {
+               unsigned long flags;
+               struct iova_fq *fq;
+
+               fq = per_cpu_ptr(iovad->fq, cpu);
+               spin_lock_irqsave(&fq->lock, flags);
+               fq_ring_free(iovad, fq);
+               spin_unlock_irqrestore(&fq->lock, flags);
+       }
+}
+
 void queue_iova(struct iova_domain *iovad,
                unsigned long pfn, unsigned long pages,
                unsigned long data)
@@ -569,6 +596,11 @@ void queue_iova(struct iova_domain *iovad,
        fq->entries[idx].counter  = atomic64_read(&iovad->fq_flush_start_cnt);
 
        spin_unlock_irqrestore(&fq->lock, flags);
+
+       if (atomic_cmpxchg(&iovad->fq_timer_on, 0, 1) == 0)
+               mod_timer(&iovad->fq_timer,
+                         jiffies + msecs_to_jiffies(IOVA_FQ_TIMEOUT));
+
        put_cpu_ptr(iovad->fq);
 }
 EXPORT_SYMBOL_GPL(queue_iova);

diff --git a/include/linux/iova.h b/include/linux/iova.h
index 913a690..d179b9b 100644 (file)
--- a/include/linux/iova.h
+++ b/include/linux/iova.h
@@ -48,6 +48,9 @@ typedef void (* iova_entry_dtor)(unsigned long data);
 /* Number of entries per Flush Queue */
 #define IOVA_FQ_SIZE   256
 
+/* Timeout (in ms) after which entries are flushed from the Flush-Queue */
+#define IOVA_FQ_TIMEOUT        10
+
 /* Flush Queue entry for defered flushing */
 struct iova_fq_entry {
        unsigned long iova_pfn;
@@ -86,6 +89,11 @@ struct iova_domain {
 
        atomic64_t      fq_flush_finish_cnt;    /* Number of TLB flushes that
                                                   have been finished */
+
+       struct timer_list fq_timer;             /* Timer to regularily empty the
+                                                  flush-queues */
+       atomic_t fq_timer_on;                   /* 1 when timer is active, 0
+                                                  when not */
 };
 
 static inline unsigned long iova_size(struct iova *iova)