diff mbox series

[v3,06/11] iommufd: Allow pt_id to carry viommu_id for IOMMU_HWPT_ALLOC

Message ID 44578ede3488d7f500a113929d44ca4f34fc2052.1728491453.git.nicolinc@nvidia.com (mailing list archive)
State New
Headers show
Series cover-letter: iommufd: Add vIOMMU infrastructure (Part-1) | expand

Commit Message

Nicolin Chen Oct. 9, 2024, 4:38 p.m. UTC 
Now a vIOMMU holds a shareable nesting parent HWPT. So, it can act like
that nesting parent HWPT to allocate a nested HWPT.

Support that in the IOMMU_HWPT_ALLOC ioctl handler, and update its kdoc.

Also, associate a vIOMMU to an allocating nested HWPT.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/iommufd/iommufd_private.h |  1 +
 include/uapi/linux/iommufd.h            | 12 ++++++------
 drivers/iommu/iommufd/hw_pagetable.c    | 24 ++++++++++++++++++++++--
 3 files changed, 29 insertions(+), 8 deletions(-)

Comments

Jason Gunthorpe Oct. 17, 2024, 5:06 p.m. UTC | #1 
On Wed, Oct 09, 2024 at 09:38:06AM -0700, Nicolin Chen wrote:
> @@ -317,6 +324,19 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
>  			goto out_unlock;
>  		}
>  		hwpt = &hwpt_nested->common;
> +	} else if (pt_obj->type == IOMMUFD_OBJ_VIOMMU) {
> +		struct iommufd_hwpt_nested *hwpt_nested;
> +		struct iommufd_viommu *viommu;
> +
> +		viommu = container_of(pt_obj, struct iommufd_viommu, obj);

One thought is to continue like we do with the domain and check that
the idev's iommu ops match the viommu's iommu ops (or is null for
default) before allowing the callback.

Jason
diff mbox series

Patch

diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 4aefac6af23f..c80d880f8b6a 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -305,6 +305,7 @@  struct iommufd_hwpt_paging {
 struct iommufd_hwpt_nested {
 	struct iommufd_hw_pagetable common;
 	struct iommufd_hwpt_paging *parent;
+	struct iommufd_viommu *viommu;
 };
 
 static inline bool hwpt_is_paging(struct iommufd_hw_pagetable *hwpt)
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index db9008a4eeef..ff8aece8212f 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -430,7 +430,7 @@  enum iommu_hwpt_data_type {
  * @size: sizeof(struct iommu_hwpt_alloc)
  * @flags: Combination of enum iommufd_hwpt_alloc_flags
  * @dev_id: The device to allocate this HWPT for
- * @pt_id: The IOAS or HWPT to connect this HWPT to
+ * @pt_id: The IOAS or HWPT or vIOMMU to connect this HWPT to
  * @out_hwpt_id: The ID of the new HWPT
  * @__reserved: Must be 0
  * @data_type: One of enum iommu_hwpt_data_type
@@ -449,11 +449,11 @@  enum iommu_hwpt_data_type {
  * IOMMU_HWPT_DATA_NONE. The HWPT can be allocated as a parent HWPT for a
  * nesting configuration by passing IOMMU_HWPT_ALLOC_NEST_PARENT via @flags.
  *
- * A user-managed nested HWPT will be created from a given parent HWPT via
- * @pt_id, in which the parent HWPT must be allocated previously via the
- * same ioctl from a given IOAS (@pt_id). In this case, the @data_type
- * must be set to a pre-defined type corresponding to an I/O page table
- * type supported by the underlying IOMMU hardware.
+ * A user-managed nested HWPT will be created from a given vIOMMU (wrapping a
+ * parent HWPT) or a parent HWPT via @pt_id, in which the parent HWPT must be
+ * allocated previously via the same ioctl from a given IOAS (@pt_id). In this
+ * case, the @data_type must be set to a pre-defined type corresponding to an
+ * I/O page table type supported by the underlying IOMMU hardware.
  *
  * If the @data_type is set to IOMMU_HWPT_DATA_NONE, @data_len and
  * @data_uptr should be zero. Otherwise, both @data_len and @data_uptr
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 77a1d30031d2..b88a638d07da 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -57,6 +57,9 @@  void iommufd_hwpt_nested_destroy(struct iommufd_object *obj)
 		container_of(obj, struct iommufd_hwpt_nested, common.obj);
 
 	__iommufd_hwpt_destroy(&hwpt_nested->common);
+
+	if (hwpt_nested->viommu)
+		refcount_dec(&hwpt_nested->viommu->obj.users);
 	refcount_dec(&hwpt_nested->parent->common.obj.users);
 }
 
@@ -213,6 +216,7 @@  iommufd_hwpt_paging_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
  */
 static struct iommufd_hwpt_nested *
 iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx,
+			  struct iommufd_viommu *viommu,
 			  struct iommufd_hwpt_paging *parent,
 			  struct iommufd_device *idev, u32 flags,
 			  const struct iommu_user_data *user_data)
@@ -235,13 +239,16 @@  iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx,
 		return ERR_CAST(hwpt_nested);
 	hwpt = &hwpt_nested->common;
 
+	if (viommu)
+		refcount_inc(&viommu->obj.users);
+	hwpt_nested->viommu = viommu;
 	refcount_inc(&parent->common.obj.users);
 	hwpt_nested->parent = parent;
 
 	hwpt->domain = ops->domain_alloc_user(idev->dev,
 					      flags & ~IOMMU_HWPT_FAULT_ID_VALID,
 					      parent->common.domain,
-					      NULL, user_data);
+					      viommu, user_data);
 	if (IS_ERR(hwpt->domain)) {
 		rc = PTR_ERR(hwpt->domain);
 		hwpt->domain = NULL;
@@ -308,7 +315,7 @@  int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
 		struct iommufd_hwpt_nested *hwpt_nested;
 
 		hwpt_nested = iommufd_hwpt_nested_alloc(
-			ucmd->ictx,
+			ucmd->ictx, NULL,
 			container_of(pt_obj, struct iommufd_hwpt_paging,
 				     common.obj),
 			idev, cmd->flags, &user_data);
@@ -317,6 +324,19 @@  int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
 			goto out_unlock;
 		}
 		hwpt = &hwpt_nested->common;
+	} else if (pt_obj->type == IOMMUFD_OBJ_VIOMMU) {
+		struct iommufd_hwpt_nested *hwpt_nested;
+		struct iommufd_viommu *viommu;
+
+		viommu = container_of(pt_obj, struct iommufd_viommu, obj);
+		hwpt_nested = iommufd_hwpt_nested_alloc(
+			ucmd->ictx, viommu, viommu->hwpt, idev,
+			cmd->flags, &user_data);
+		if (IS_ERR(hwpt_nested)) {
+			rc = PTR_ERR(hwpt_nested);
+			goto out_unlock;
+		}
+		hwpt = &hwpt_nested->common;
 	} else {
 		rc = -EINVAL;
 		goto out_put_pt;