iommu: Do not use IOMMU_DOMAIN_DMA if CONFIG_IOMMU_DMA is not enabled

msm_iommu platforms do not select either CONFIG_IOMMU_DMA or
CONFIG_ARM_DMA_USE_IOMMU so they create a IOMMU_DOMAIN_DMA domain by
default and never populate it. This acts like a BLOCKED domain and breaks
the GPU driver on the platform.

Detect this and force use of IDENTITY instead.

Fixes: 98ac73f99bc4 ("iommu: Require a default_domain for all iommu drivers")
Reported-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/linux-iommu/CAA8EJprz7VVmBG68U9zLuqPd0UdSRHYoLDJSP6tCj6H6qanuTQ@mail.gmail.com/
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/0-v1-20700abdf239+19c-iommu_no_dma_iommu_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 1ecac2b5c54f4a9bb3a250734d3354114392a5ae..21d45e6a5931a137efe54ad56066e6a5502c60f5 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1920,6 +1920,18 @@ static int iommu_get_default_domain_type(struct iommu_group *group,
                }
        }
 
+       /*
+        * If the common dma ops are not selected in kconfig then we cannot use
+        * IOMMU_DOMAIN_DMA at all. Force IDENTITY if nothing else has been
+        * selected.
+        */
+       if (!IS_ENABLED(CONFIG_IOMMU_DMA)) {
+               if (WARN_ON(driver_type == IOMMU_DOMAIN_DMA))
+                       return -1;
+               if (!driver_type)
+                       driver_type = IOMMU_DOMAIN_IDENTITY;
+       }
+
        if (untrusted) {
                if (driver_type && driver_type != IOMMU_DOMAIN_DMA) {
                        dev_err_ratelimited(