amd-iommu: disable round-robin allocator for CONFIG_IOMMU_STRESS

Disabling the round-robin allocator results in reusing the same
dma-addresses again very fast. This is a good test if the iotlb flushing
is working correctly.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 31d56c36010a..543822b39a84 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -783,6 +783,11 @@ static unsigned long dma_ops_alloc_addresses(struct device *dev,
 {
         unsigned long address;
 
+#ifdef CONFIG_IOMMU_STRESS
+        dom->next_address = 0;
+        dom->need_flush = true;
+#endif
+
         address = dma_ops_area_alloc(dev, dom, pages, align_mask,
                                      dma_mask, dom->next_address);