iommu: Pass in parent domain with user_data to domain_alloc_user op

domain_alloc_user op already accepts user flags for domain allocation, add
a parent domain pointer and a driver specific user data support as well.
The user data would be tagged with a type for iommu drivers to add their
own driver specific user data per hw_pagetable.

Add a struct iommu_user_data as a bundle of data_ptr/data_len/type from an
iommufd core uAPI structure. Make the user data opaque to the core, since
a userspace driver must match the kernel driver. In the future, if drivers
share some common parameter, there would be a generic parameter as well.

Link: https://lore.kernel.org/r/20231026043938.63898-7-yi.l.liu@intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Co-developed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

4 files changed, 20 insertions, 6 deletions

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index caad10f9cee3..b399c5741378 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2219,12 +2219,15 @@ static struct iommu_domain *amd_iommu_domain_alloc(unsigned int type)
 	return domain;
 }
 
-static struct iommu_domain *amd_iommu_domain_alloc_user(struct device *dev,
-							u32 flags)
+static struct iommu_domain *
+amd_iommu_domain_alloc_user(struct device *dev, u32 flags,
+			    struct iommu_domain *parent,
+			    const struct iommu_user_data *user_data)
+
 {
 	unsigned int type = IOMMU_DOMAIN_UNMANAGED;
 
-	if (flags & ~IOMMU_HWPT_ALLOC_DIRTY_TRACKING)
+	if ((flags & ~IOMMU_HWPT_ALLOC_DIRTY_TRACKING) || parent || user_data)
 		return ERR_PTR(-EOPNOTSUPP);
 
 	return do_iommu_domain_alloc(type, dev, flags);
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index eb92a201cc0b..fe67f8d77b09 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4076,7 +4076,9 @@ static struct iommu_domain *intel_iommu_domain_alloc(unsigned type)
 }
 
 static struct iommu_domain *
-intel_iommu_domain_alloc_user(struct device *dev, u32 flags)
+intel_iommu_domain_alloc_user(struct device *dev, u32 flags,
+			      struct iommu_domain *parent,
+			      const struct iommu_user_data *user_data)
 {
 	struct iommu_domain *domain;
 	struct intel_iommu *iommu;
@@ -4086,6 +4088,9 @@ intel_iommu_domain_alloc_user(struct device *dev, u32 flags)
 	    (~(IOMMU_HWPT_ALLOC_NEST_PARENT | IOMMU_HWPT_ALLOC_DIRTY_TRACKING)))
 		return ERR_PTR(-EOPNOTSUPP);
 
+	if (parent || user_data)
+		return ERR_PTR(-EOPNOTSUPP);
+
 	iommu = device_to_iommu(dev, NULL, NULL);
 	if (!iommu)
 		return ERR_PTR(-ENODEV);
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 6bce9af0cb8d..198ecbd536f7 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -108,7 +108,8 @@ iommufd_hwpt_paging_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
 	hwpt_paging->ioas = ioas;
 
 	if (ops->domain_alloc_user) {
-		hwpt->domain = ops->domain_alloc_user(idev->dev, flags);
+		hwpt->domain =
+			ops->domain_alloc_user(idev->dev, flags, NULL, NULL);
 		if (IS_ERR(hwpt->domain)) {
 			rc = PTR_ERR(hwpt->domain);
 			hwpt->domain = NULL;
diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
index 068928ba7950..d71007234896 100644
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@ -241,7 +241,9 @@ static struct iommu_domain *mock_domain_alloc(unsigned int iommu_domain_type)
 }
 
 static struct iommu_domain *
-mock_domain_alloc_user(struct device *dev, u32 flags)
+mock_domain_alloc_user(struct device *dev, u32 flags,
+		       struct iommu_domain *parent,
+		       const struct iommu_user_data *user_data)
 {
 	struct mock_dev *mdev = container_of(dev, struct mock_dev, dev);
 	struct iommu_domain *domain;
@@ -250,6 +252,9 @@ mock_domain_alloc_user(struct device *dev, u32 flags)
 	    (~(IOMMU_HWPT_ALLOC_NEST_PARENT | IOMMU_HWPT_ALLOC_DIRTY_TRACKING)))
 		return ERR_PTR(-EOPNOTSUPP);
 
+	if (parent || user_data)
+		return ERR_PTR(-EOPNOTSUPP);
+
 	if ((flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING) &&
 	    (mdev->flags & MOCK_FLAGS_DEVICE_NO_DIRTY))
 		return ERR_PTR(-EOPNOTSUPP);