On 3/9/23 4:09 PM, Yi Liu wrote:
Nested translation has stage-1 and stage-2 page tables. A stage-1 page
table is managed by user space, and it needs to work with a stage-2 page
table, which is a parent hwpt for the stage-1 hwpt.
iommu core already supports accepting parent iommu_domain and user_data
to allocate an iommu_domain. This makes iommufd_hw_pagetable_alloc() to
accept the parent hwpt and user_data, and relays them to iommu core, to
prepare for supporting hw_pagetable allocation with user_data.
Also, add a parent pointer in struct iommufd_hw_pagetable for taking and
releasing its refcount.
Co-developed-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
---
drivers/iommu/iommufd/device.c | 2 +-
drivers/iommu/iommufd/hw_pagetable.c | 28 ++++++++++++++++++++++---
drivers/iommu/iommufd/iommufd_private.h | 5 ++++-
3 files changed, 30 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 5c352807d946..19cd6df46c6a 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -558,7 +558,7 @@ iommufd_device_auto_get_domain(struct iommufd_device *idev,
}
hwpt = iommufd_hw_pagetable_alloc(idev->ictx, ioas, idev,
- immediate_attach);
+ NULL, NULL, immediate_attach);
if (IS_ERR(hwpt)) {
destroy_hwpt = ERR_CAST(hwpt);
goto out_unlock;
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 84b4a11e62f8..16e92a1c150b 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -24,6 +24,8 @@ void iommufd_hw_pagetable_destroy(struct iommufd_object *obj)
if (hwpt->domain)
iommu_domain_free(hwpt->domain);
+ if (hwpt->parent)
+ refcount_dec(&hwpt->parent->obj.users);
refcount_dec(&hwpt->ioas->obj.users);
}
@@ -46,6 +48,8 @@ int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
* @ictx: iommufd context
* @ioas: IOAS to associate the domain with
* @idev: Device to get an iommu_domain for
+ * @parent: Optional parent HWPT to associate with the domain with
+ * @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
@@ -54,14 +58,20 @@ int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
*/
struct iommufd_hw_pagetable *
iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
- struct iommufd_device *idev, bool immediate_attach)
+ struct iommufd_device *idev,
+ struct iommufd_hw_pagetable *parent,
+ void *user_data, bool immediate_attach)
{
const struct iommu_ops *ops = dev_iommu_ops(idev->dev);
+ struct iommu_domain *parent_domain = NULL;
struct iommufd_hw_pagetable *hwpt;
int rc;
lockdep_assert_held(&ioas->mutex);
+ if (parent && !ops->domain_alloc_user)
+ return ERR_PTR(-EOPNOTSUPP);
My understanding here is that we are checking whether domain_alloc_user
is required. It seems that as long as the caller inputs a valid
user_data or parent, domain_alloc_user is required. If so,
if ((user_data || parent) && !ops->domain_alloc_user)
return ERR_PTR(-EOPNOTSUPP);
Best regards,
baolu
