[PATCH 08/10] vfio: introduce vfio_group_require_msi_mapping

[Eric Auger <eric.auger@linaro.org>]

This new function enables to know whether msi write transaction
addresses must be mapped.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
---
 drivers/vfio/vfio.c             | 22 ++++++++++++++++++++++
 drivers/vfio/vfio_iommu_type1.c |  8 ++++++++
 include/linux/vfio.h            |  2 ++
 3 files changed, 32 insertions(+)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 2760d4c..f3df5a10 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -793,6 +793,28 @@ static int vfio_iommu_group_notifier(struct notifier_block *nb,
 	return NOTIFY_OK;
 }
 
+bool vfio_group_require_msi_mapping(struct vfio_group *group)
+{
+	struct vfio_container *container = group->container;
+	struct vfio_iommu_driver *driver;
+	bool ret;
+
+	down_read(&container->group_lock);
+
+	driver = container->iommu_driver;
+	if (!driver || !driver->ops || !driver->ops->require_msi_mapping) {
+		ret = -EINVAL;
+		goto up;
+	}
+
+	ret = driver->ops->require_msi_mapping(container->iommu_data);
+
+up:
+	up_read(&container->group_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(vfio_group_require_msi_mapping);
+
 /**
  * VFIO driver API
  */
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index a79e2a8..2f085d3 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1179,6 +1179,13 @@ unlock:
 	return ret;
 }
 
+static bool vfio_iommu_type1_require_msi_mapping(void *iommu_data)
+{
+	struct vfio_iommu *iommu = iommu_data;
+
+	return vfio_domains_require_msi_mapping(iommu);
+}
+
 static void *vfio_iommu_type1_open(unsigned long arg)
 {
 	struct vfio_iommu *iommu;
@@ -1336,6 +1343,7 @@ static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = {
 		vfio_iommu_type1_alloc_map_reserved_iova,
 	.unmap_free_reserved_iova	=
 		vfio_iommu_type1_unmap_free_reserved_iova,
+	.require_msi_mapping		= vfio_iommu_type1_require_msi_mapping,
 };
 
 static int __init vfio_iommu_type1_init(void)
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index f7eaf30..3e6cbeb 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -58,6 +58,7 @@ extern void *vfio_del_group_dev(struct device *dev);
 extern struct vfio_device *vfio_device_get_from_dev(struct device *dev);
 extern void vfio_device_put(struct vfio_device *device);
 extern void *vfio_device_data(struct vfio_device *device);
+extern bool vfio_group_require_msi_mapping(struct vfio_group *group);
 
 /**
  * struct vfio_iommu_driver_ops - VFIO IOMMU driver callbacks
@@ -85,6 +86,7 @@ struct vfio_iommu_driver_ops {
 	int		(*unmap_free_reserved_iova)(void *iommu_data,
 						    struct iommu_group *group,
 						    dma_addr_t iova);
+	bool		(*require_msi_mapping)(void *iommu_data);
 };
 
 extern int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops);
-- 
1.9.1