[PATCH v2 05/11] iommufd/hw_pagetable: Do not populate user-managed hw_pagetables

Yi Liu
2023-05-11T14:43:26Z

From: Nicolin Chen <nicolinc@nvidia.com>

A user-managed hw_pagetable does not need to get populated, since it is
managed by a guest OS. Move the iopt_table_add_domain and list_add_tail
calls into a helper, where the hwpt pointer will be redirected to its
hwpt->parent if it's available.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
drivers/iommu/iommufd/hw_pagetable.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index ec9b140939ce..73d7d9d07726 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -58,6 +58,24 @@ int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
return 0;
}

+static int iommufd_hw_pagetable_link_ioas(struct iommufd_hw_pagetable *hwpt)
+{
+ int rc;
+
+ /*
+ * Only a parent hwpt needs to be linked to the IOAS. And a hwpt->parent
+ * must be linked to the IOAS already, when it's being allocated.
+ */
+ if (hwpt->parent)
+ return 0;
+
+ rc = iopt_table_add_domain(&hwpt->ioas->iopt, hwpt->domain);
+ if (rc)
+ return rc;
+ list_add_tail(&hwpt->hwpt_item, &hwpt->ioas->hwpt_list);
+ return 0;
+}
+
/**
* iommufd_hw_pagetable_alloc() - Get an iommu_domain for a device
* @ictx: iommufd context
@@ -151,10 +169,9 @@ iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
goto out_abort;
}

- rc = iopt_table_add_domain(&hwpt->ioas->iopt, hwpt->domain);
+ rc = iommufd_hw_pagetable_link_ioas(hwpt);
if (rc)
goto out_detach;
- list_add_tail(&hwpt->hwpt_item, &hwpt->ioas->hwpt_list);
return hwpt;

out_detach:
--
2.34.1