iommu/amd: Do not force direct mapping when SME is active

Do not force devices supporting IOMMUv2 to be direct mapped when memory
encryption is active. This might cause them to be unusable because their
DMA mask does not include the encryption bit.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20200824105415.21000-2-joro@8bytes.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index a382d7a73eaa33d563b61ae04da2e00d3869dc0f..07ae8b93887e564b31afc30e15b6d12972da56ee 100644 (file)
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2659,7 +2659,12 @@ static int amd_iommu_def_domain_type(struct device *dev)
        if (!dev_data)
                return 0;
 
-       if (dev_data->iommu_v2)
+       /*
+        * Do not identity map IOMMUv2 capable devices when memory encryption is
+        * active, because some of those devices (AMD GPUs) don't have the
+        * encryption bit in their DMA-mask and require remapping.
+        */
+       if (!mem_encrypt_active() && dev_data->iommu_v2)
                return IOMMU_DOMAIN_IDENTITY;
 
        return 0;