iommufd: Add iommufd_ctx_has_group()

This adds the helper to check if any device within the given iommu_group
has been bound with the iommufd_ctx. This is helpful for the checking on
device ownership for the devices which have not been bound but cannot be
bound to any other iommufd_ctx as the iommu_group has been bound.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Yanting Jiang <yanting.jiang@intel.com>
Tested-by: Terrence Xu <terrence.xu@intel.com>
Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20230718105542.4138-5-yi.l.liu@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 29d0566..693c215 100644 (file)
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -99,6 +99,36 @@ out_group_put:
 EXPORT_SYMBOL_NS_GPL(iommufd_device_bind, IOMMUFD);
 
 /**
+ * iommufd_ctx_has_group - True if any device within the group is bound
+ *                         to the ictx
+ * @ictx: iommufd file descriptor
+ * @group: Pointer to a physical iommu_group struct
+ *
+ * True if any device within the group has been bound to this ictx, ex. via
+ * iommufd_device_bind(), therefore implying ictx ownership of the group.
+ */
+bool iommufd_ctx_has_group(struct iommufd_ctx *ictx, struct iommu_group *group)
+{
+       struct iommufd_object *obj;
+       unsigned long index;
+
+       if (!ictx || !group)
+               return false;
+
+       xa_lock(&ictx->objects);
+       xa_for_each(&ictx->objects, index, obj) {
+               if (obj->type == IOMMUFD_OBJ_DEVICE &&
+                   container_of(obj, struct iommufd_device, obj)->group == group) {
+                       xa_unlock(&ictx->objects);
+                       return true;
+               }
+       }
+       xa_unlock(&ictx->objects);
+       return false;
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_ctx_has_group, IOMMUFD);
+
+/**
  * iommufd_device_unbind - Undo iommufd_device_bind()
  * @idev: Device returned by iommufd_device_bind()
  *

diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 1129a36..f241baf 100644 (file)
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -16,6 +16,7 @@ struct page;
 struct iommufd_ctx;
 struct iommufd_access;
 struct file;
+struct iommu_group;
 
 struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
                                           struct device *dev, u32 *id);
@@ -50,6 +51,7 @@ void iommufd_ctx_get(struct iommufd_ctx *ictx);
 #if IS_ENABLED(CONFIG_IOMMUFD)
 struct iommufd_ctx *iommufd_ctx_from_file(struct file *file);
 void iommufd_ctx_put(struct iommufd_ctx *ictx);
+bool iommufd_ctx_has_group(struct iommufd_ctx *ictx, struct iommu_group *group);
 
 int iommufd_access_pin_pages(struct iommufd_access *access, unsigned long iova,
                             unsigned long length, struct page **out_pages,