amd-iommu: don't free dma adresses below 512MB with CONFIG_IOMMU_STRESS

This will test the automatic aperture enlargement code. This is
important because only very few devices will ever trigger this code
path. So force it under CONFIG_IOMMU_STRESS.

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 33434c497a6a..04ff5ec4ac0e 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -824,6 +824,11 @@ static void dma_ops_free_addresses(struct dma_ops_domain *dom,
 
         BUG_ON(i >= APERTURE_MAX_RANGES || range == NULL);
 
+#ifdef CONFIG_IOMMU_STRESS
+        if (i < 4)
+                return;
+#endif
+
         if (address >= dom->next_address)
                 dom->need_flush = true;