summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--Documentation/kernel-parameters.txt7
-rw-r--r--arch/s390/pci/pci_dma.c50
2 files changed, 43 insertions, 14 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index b7fa2f599459..c848095f2cb0 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3023,6 +3023,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
S [KNL] Run init in single mode
+ s390_iommu= [HW,S390]
+ Set s390 IOTLB flushing mode
+ strict
+ With strict flushing every unmap operation will result in
+ an IOTLB flush. Default is lazy flushing before reuse,
+ which is faster.
+
sa1100ir [NET]
See drivers/net/irda/sa1100_ir.c.
diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index f91c03119804..4cbb29a4d615 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -16,6 +16,13 @@
static struct kmem_cache *dma_region_table_cache;
static struct kmem_cache *dma_page_table_cache;
+static int s390_iommu_strict;
+
+static int zpci_refresh_global(struct zpci_dev *zdev)
+{
+ return zpci_refresh_trans((u64) zdev->fh << 32, zdev->start_dma,
+ zdev->iommu_pages * PAGE_SIZE);
+}
static unsigned long *dma_alloc_cpu_table(void)
{
@@ -155,18 +162,15 @@ static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
}
/*
- * rpcit is not required to establish new translations when previously
- * invalid translation-table entries are validated, however it is
- * required when altering previously valid entries.
+ * With zdev->tlb_refresh == 0, rpcit is not required to establish new
+ * translations when previously invalid translation-table entries are
+ * validated. With lazy unmap, it also is skipped for previously valid
+ * entries, but a global rpcit is then required before any address can
+ * be re-used, i.e. after each iommu bitmap wrap-around.
*/
if (!zdev->tlb_refresh &&
- ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID))
- /*
- * TODO: also need to check that the old entry is indeed INVALID
- * and not only for one page but for the whole range...
- * -> now we WARN_ON in that case but with lazy unmap that
- * needs to be redone!
- */
+ (!s390_iommu_strict ||
+ ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)))
goto no_refresh;
rc = zpci_refresh_trans((u64) zdev->fh << 32, start_dma_addr,
@@ -220,16 +224,21 @@ static unsigned long __dma_alloc_iommu(struct zpci_dev *zdev,
static unsigned long dma_alloc_iommu(struct zpci_dev *zdev, int size)
{
unsigned long offset, flags;
+ int wrap = 0;
spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
offset = __dma_alloc_iommu(zdev, zdev->next_bit, size);
- if (offset == -1)
+ if (offset == -1) {
+ /* wrap-around */
offset = __dma_alloc_iommu(zdev, 0, size);
+ wrap = 1;
+ }
if (offset != -1) {
zdev->next_bit = offset + size;
- if (zdev->next_bit >= zdev->iommu_pages)
- zdev->next_bit = 0;
+ if (!zdev->tlb_refresh && !s390_iommu_strict && wrap)
+ /* global flush after wrap-around with lazy unmap */
+ zpci_refresh_global(zdev);
}
spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
return offset;
@@ -243,7 +252,11 @@ static void dma_free_iommu(struct zpci_dev *zdev, unsigned long offset, int size
if (!zdev->iommu_bitmap)
goto out;
bitmap_clear(zdev->iommu_bitmap, offset, size);
- if (offset >= zdev->next_bit)
+ /*
+ * Lazy flush for unmap: need to move next_bit to avoid address re-use
+ * until wrap-around.
+ */
+ if (!s390_iommu_strict && offset >= zdev->next_bit)
zdev->next_bit = offset + size;
out:
spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
@@ -504,3 +517,12 @@ struct dma_map_ops s390_dma_ops = {
/* dma_supported is unconditionally true without a callback */
};
EXPORT_SYMBOL_GPL(s390_dma_ops);
+
+static int __init s390_iommu_setup(char *str)
+{
+ if (!strncmp(str, "strict", 6))
+ s390_iommu_strict = 1;
+ return 0;
+}
+
+__setup("s390_iommu=", s390_iommu_setup);