[RFC PATCH v4 03/10] VFIO_IOMMU_TYPE1: workaround to build for platform devices

Antonios Motakis
2014-02-08T17:32:15Z

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.motakis@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 26b3d9d..bd50721 100644
--- a/drivers/vfio/Kconfig
+++ b/drivers/vfio/Kconfig
@@ -11,7 +11,7 @@ config VFIO_IOMMU_SPAPR_TCE
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
select VFIO_IOMMU_SPAPR_TCE if (PPC_POWERNV || PPC_PSERIES)
help
VFIO provides a framework for secure userspace device drivers.
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index ad7a1f6..81e65f4 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/rbtree.h>
#include <linux/sched.h>
#include <linux/slab.h>
@@ -47,6 +48,8 @@ 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;

static bool disable_hugepages;
module_param_named(disable_hugepages,
@@ -785,7 +788,8 @@ 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);
@@ -797,7 +801,7 @@ 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__);
@@ -914,7 +918,17 @@ 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);
--
1.8.3.2