[PATCH v4 05/17] iommufd: Separate kernel-managed HWPT alloc/destroy/abort functions

[Yi Liu]

From: Nicolin Chen <nicolinc@xxxxxxxxxx>

As one of the previous commits mentioned, a user-managed HWPT will have
some different attributes/members. It'd be more clear by having separate
allocators. Since the existing iommufd_hw_pagetable_alloc() serves well
kernel-managed HWPTs, apply some minimal updates to mark it as a kernel-
managed HWPT allocator.

Also, add a pair of function pointers (abort and destroy) in the struct,
to separate different cleanup routines. Then rename the existing cleanup
functions to iommufd_kernel_managed_hwpt_destroy/abort() linked to the
HWPT in the allocator.

Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
---
 drivers/iommu/iommufd/hw_pagetable.c    | 34 ++++++++++++++++++++-----
 drivers/iommu/iommufd/iommufd_private.h |  3 +++
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 554a9c3d740f..1cc7178121d1 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -8,7 +8,7 @@
 #include "../iommu-priv.h"
 #include "iommufd_private.h"
 
-void iommufd_hw_pagetable_destroy(struct iommufd_object *obj)
+static void iommufd_kernel_managed_hwpt_destroy(struct iommufd_object *obj)
 {
 	struct iommufd_hw_pagetable *hwpt =
 		container_of(obj, struct iommufd_hw_pagetable, obj);
@@ -27,7 +27,12 @@ void iommufd_hw_pagetable_destroy(struct iommufd_object *obj)
 	refcount_dec(&hwpt->ioas->obj.users);
 }
 
-void iommufd_hw_pagetable_abort(struct iommufd_object *obj)
+void iommufd_hw_pagetable_destroy(struct iommufd_object *obj)
+{
+	container_of(obj, struct iommufd_hw_pagetable, obj)->destroy(obj);
+}
+
+static void iommufd_kernel_managed_hwpt_abort(struct iommufd_object *obj)
 {
 	struct iommufd_hw_pagetable *hwpt =
 		container_of(obj, struct iommufd_hw_pagetable, obj);
@@ -42,6 +47,11 @@ void iommufd_hw_pagetable_abort(struct iommufd_object *obj)
 	iommufd_hw_pagetable_destroy(obj);
 }
 
+void iommufd_hw_pagetable_abort(struct iommufd_object *obj)
+{
+	container_of(obj, struct iommufd_hw_pagetable, obj)->abort(obj);
+}
+
 int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
 {
 	if (hwpt->enforce_cache_coherency)
@@ -57,7 +67,7 @@ int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
 }
 
 /**
- * iommufd_hw_pagetable_alloc() - Get an iommu_domain for a device
+ * iommufd_hw_pagetable_alloc() - Get a kernel-managed iommu_domain for a device
  * @ictx: iommufd context
  * @ioas: IOAS to associate the domain with
  * @idev: Device to get an iommu_domain for
@@ -66,9 +76,9 @@ int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
  * @user_data: Optional user_data pointer
  * @immediate_attach: True if idev should be attached to the hwpt
  *
- * Allocate a new iommu_domain and return it as a hw_pagetable. The HWPT
- * will be linked to the given ioas and upon return the underlying iommu_domain
- * is fully popoulated.
+ * Allocate a new iommu_domain (must be IOMMU_DOMAIN_UNMANAGED) and return it as
+ * a kernel-managed hw_pagetable. The HWPT will be linked to the given ioas and
+ * upon return the underlying iommu_domain is fully popoulated.
  *
  * The caller must hold the ioas->mutex until after
  * iommufd_object_abort_and_destroy() or iommufd_object_finalize() is called on
@@ -103,6 +113,8 @@ iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
 	/* Pairs with iommufd_hw_pagetable_destroy() */
 	refcount_inc(&ioas->obj.users);
 	hwpt->ioas = ioas;
+	hwpt->abort = iommufd_kernel_managed_hwpt_abort;
+	hwpt->destroy = iommufd_kernel_managed_hwpt_destroy;
 
 	if (ops->domain_alloc_user) {
 		hwpt->domain = ops->domain_alloc_user(idev->dev, flags,
@@ -121,6 +133,16 @@ iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
 		}
 	}
 
+	if (WARN_ON_ONCE(hwpt->domain->type != IOMMU_DOMAIN_UNMANAGED)) {
+		rc = -EINVAL;
+		goto out_abort;
+	}
+	/* Driver is buggy by mixing user-managed op in kernel-managed ops */
+	if (WARN_ON_ONCE(hwpt->domain->ops->cache_invalidate_user)) {
+		rc = -EINVAL;
+		goto out_abort;
+	}
+
 	/*
 	 * Set the coherency mode before we do iopt_table_add_domain() as some
 	 * iommus have a per-PTE bit that controls it and need to decide before
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 1d3b1a74e854..3e89c3d530f3 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -234,6 +234,9 @@ struct iommufd_hw_pagetable {
 	struct iommufd_object obj;
 	struct iommu_domain *domain;
 
+	void (*abort)(struct iommufd_object *obj);
+	void (*destroy)(struct iommufd_object *obj);
+
 	union {
 		struct { /* kernel-managed */
 			struct iommufd_ioas *ioas;
-- 
2.34.1