This is a workaround to make the VFIO_IOMMU_TYPE1 driver usable with
platform devices instead of PCI. A future permanent fix should support
both. This is required in order to use the Exynos SMMU, or ARM SMMU
driver with VFIO.

Signed-off-by: Antonios Motakis <a.mota...@virtualopensystems.com>
---
 drivers/vfio/Kconfig            |  2 +-
 drivers/vfio/vfio_iommu_type1.c | 22 ++++++++++++++++++----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
index 7cd5dec..1f84eda 100644
--- a/drivers/vfio/Kconfig
+++ b/drivers/vfio/Kconfig
@@ -6,7 +6,7 @@ config VFIO_IOMMU_TYPE1
 menuconfig VFIO
        tristate "VFIO Non-Privileged userspace driver framework"
        depends on IOMMU_API
-       select VFIO_IOMMU_TYPE1 if X86
+       select VFIO_IOMMU_TYPE1 if X86 || ARM
        help
          VFIO provides a framework for secure userspace device drivers.
          See Documentation/vfio.txt for more details.
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 6f3fbc4..d7e6a12 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -30,7 +30,8 @@
 #include <linux/iommu.h>
 #include <linux/module.h>
 #include <linux/mm.h>
-#include <linux/pci.h>         /* pci_bus_type */
+#include <linux/pci.h>                 /* pci_bus_type */
+#include <linux/platform_device.h>     /* platform_bus_type */
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
@@ -46,6 +47,8 @@ module_param_named(allow_unsafe_interrupts,
                   allow_unsafe_interrupts, bool, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(allow_unsafe_interrupts,
                 "Enable VFIO IOMMU support for on platforms without interrupt 
remapping support.");
+static struct bus_type *iommu_bus_type = NULL;
+static bool require_cap_intr_remap = false;
 
 struct vfio_iommu {
        struct iommu_domain     *domain;
@@ -612,7 +615,8 @@ static void *vfio_iommu_type1_open(unsigned long arg)
        /*
         * Wish we didn't have to know about bus_type here.
         */
-       iommu->domain = iommu_domain_alloc(&pci_bus_type);
+       iommu->domain = iommu_domain_alloc(iommu_bus_type);
+
        if (!iommu->domain) {
                kfree(iommu);
                return ERR_PTR(-EIO);
@@ -624,7 +628,7 @@ static void *vfio_iommu_type1_open(unsigned long arg)
         * the way.  Fortunately we know interrupt remapping is global for
         * our iommus.
         */
-       if (!allow_unsafe_interrupts &&
+       if (require_cap_intr_remap && !allow_unsafe_interrupts &&
            !iommu_domain_has_cap(iommu->domain, IOMMU_CAP_INTR_REMAP)) {
                pr_warn("%s: No interrupt remapping support.  Use the module 
param \"allow_unsafe_interrupts\" to enable VFIO IOMMU support on this 
platform\n",
                       __func__);
@@ -733,7 +737,17 @@ static const struct vfio_iommu_driver_ops 
vfio_iommu_driver_ops_type1 = {
 
 static int __init vfio_iommu_type1_init(void)
 {
-       if (!iommu_present(&pci_bus_type))
+#ifdef CONFIG_PCI
+       if (iommu_present(&pci_bus_type)) {
+               iommu_bus_type = &pci_bus_type;
+               /* For PCI targets, IOMMU_CAP_INTR_REMAP is required */
+               require_cap_intr_remap = true;
+       }
+#endif
+       if (!iommu_bus_type && iommu_present(&platform_bus_type))
+               iommu_bus_type = &platform_bus_type;
+
+       if(!iommu_bus_type)
                return -ENODEV;
 
        return vfio_register_iommu_driver(&vfio_iommu_driver_ops_type1);
-- 
1.8.1.2

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