[PATCH 5/5] iommu/amd: Set global dma_ops if swiotlb is disabled

From: Joerg Roedel
Date: Tue Jul 28 2015 - 11:01:28 EST


From: Joerg Roedel <jroedel@xxxxxxx>

Some AMD systems also have non-PCI devices which can do DMA.
Those can't be handled by the AMD IOMMU, as the hardware can
only handle PCI. These devices would end up with no dma_ops,
as neither the per-device nor the global dma_ops will get
set. SWIOTLB provides global dma_ops when it is active, so
make sure there are global dma_ops too when swiotlb is
disabled.

Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
drivers/iommu/amd_iommu.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index e29baa6..fa9508b 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2853,6 +2853,15 @@ int __init amd_iommu_init_dma_ops(void)
swiotlb = iommu_pass_through ? 1 : 0;
iommu_detected = 1;

+ /*
+ * In case we don't initialize SWIOTLB (actually the common case
+ * when AMD IOMMU is enabled), make sure there are global
+ * dma_ops set as a fall-back for devices not handled by this
+ * driver (for example non-PCI devices).
+ */
+ if (!swiotlb)
+ dma_ops = &nommu_dma_ops;
+
amd_iommu_stats_init();

if (amd_iommu_unmap_flush)
--
1.9.1

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