vfio/type1: Add vfio_group_iommu_domain()

Add the API for getting the domain from a vfio group. This could be used
by the physical device drivers which rely on the vfio/mdev framework for
mediated device user level access. The typical use case like below:

	unsigned int pasid;
	struct vfio_group *vfio_group;
	struct iommu_domain *iommu_domain;
	struct device *dev = mdev_dev(mdev);
	struct device *iommu_device = mdev_get_iommu_device(dev);

	if (!iommu_device ||
	    !iommu_dev_feature_enabled(iommu_device, IOMMU_DEV_FEAT_AUX))
		return -EINVAL;

	vfio_group = vfio_group_get_external_user_from_dev(dev);
	if (IS_ERR_OR_NULL(vfio_group))
		return -EFAULT;

	iommu_domain = vfio_group_iommu_domain(vfio_group);
	if (IS_ERR_OR_NULL(iommu_domain)) {
		vfio_group_put_external_user(vfio_group);
		return -EFAULT;
	}

	pasid = iommu_aux_get_pasid(iommu_domain, iommu_device);
	if (pasid < 0) {
		vfio_group_put_external_user(vfio_group);
		return -EFAULT;
	}

	/* Program device context with pasid value. */
	...

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 2151bc7..4ad8a35 100644 (file)
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -2331,6 +2331,24 @@ int vfio_unregister_notifier(struct device *dev, enum vfio_notify_type type,
 }
 EXPORT_SYMBOL(vfio_unregister_notifier);
 
+struct iommu_domain *vfio_group_iommu_domain(struct vfio_group *group)
+{
+       struct vfio_container *container;
+       struct vfio_iommu_driver *driver;
+
+       if (!group)
+               return ERR_PTR(-EINVAL);
+
+       container = group->container;
+       driver = container->iommu_driver;
+       if (likely(driver && driver->ops->group_iommu_domain))
+               return driver->ops->group_iommu_domain(container->iommu_data,
+                                                      group->iommu_group);
+
+       return ERR_PTR(-ENOTTY);
+}
+EXPORT_SYMBOL_GPL(vfio_group_iommu_domain);
+
 /**
  * Module/class support
  */

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 67e8276..0b4deda 100644 (file)
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -2980,6 +2980,29 @@ static int vfio_iommu_type1_dma_rw(void *iommu_data, dma_addr_t user_iova,
        return ret;
 }
 
+static struct iommu_domain *
+vfio_iommu_type1_group_iommu_domain(void *iommu_data,
+                                   struct iommu_group *iommu_group)
+{
+       struct iommu_domain *domain = ERR_PTR(-ENODEV);
+       struct vfio_iommu *iommu = iommu_data;
+       struct vfio_domain *d;
+
+       if (!iommu || !iommu_group)
+               return ERR_PTR(-EINVAL);
+
+       mutex_lock(&iommu->lock);
+       list_for_each_entry(d, &iommu->domain_list, next) {
+               if (find_iommu_group(d, iommu_group)) {
+                       domain = d->domain;
+                       break;
+               }
+       }
+       mutex_unlock(&iommu->lock);
+
+       return domain;
+}
+
 static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = {
        .name                   = "vfio-iommu-type1",
        .owner                  = THIS_MODULE,
@@ -2993,6 +3016,7 @@ static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = {
        .register_notifier      = vfio_iommu_type1_register_notifier,
        .unregister_notifier    = vfio_iommu_type1_unregister_notifier,
        .dma_rw                 = vfio_iommu_type1_dma_rw,
+       .group_iommu_domain     = vfio_iommu_type1_group_iommu_domain,
 };
 
 static int __init vfio_iommu_type1_init(void)

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 38d3c6a..f45940b 100644 (file)
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -90,6 +90,8 @@ struct vfio_iommu_driver_ops {
                                               struct notifier_block *nb);
        int             (*dma_rw)(void *iommu_data, dma_addr_t user_iova,
                                  void *data, size_t count, bool write);
+       struct iommu_domain *(*group_iommu_domain)(void *iommu_data,
+                                                  struct iommu_group *group);
 };
 
 extern int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops);
@@ -126,6 +128,8 @@ extern int vfio_group_unpin_pages(struct vfio_group *group,
 extern int vfio_dma_rw(struct vfio_group *group, dma_addr_t user_iova,
                       void *data, size_t len, bool write);
 
+extern struct iommu_domain *vfio_group_iommu_domain(struct vfio_group *group);
+
 /* each type has independent events */
 enum vfio_notify_type {
        VFIO_IOMMU_NOTIFY = 0,