iommu/amd: Set global dma_ops if swiotlb is disabled

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@suse.de>

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)