[PATCH v6 02/10] iommu: Pass in parent domain with user_data to domain_alloc_user op

Yi Liu
2023-10-24T15:09:55Z

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.

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.

Define an enum iommu_hwpt_data_type (with IOMMU_HWPT_DATA_NONE type) for
iommu drivers to add their own driver specific user data per hw_pagetable.

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>
---
drivers/iommu/intel/iommu.c | 7 ++++++-
drivers/iommu/iommufd/hw_pagetable.c | 3 ++-
drivers/iommu/iommufd/selftest.c | 7 ++++++-
include/linux/iommu.h | 27 ++++++++++++++++++++++++---
include/uapi/linux/iommufd.h | 8 ++++++++
5 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 65f46f1347e6..cb64759b3d95 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 c2b742ffeb0c..97b84d681e09 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -96,7 +96,8 @@ iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
hwpt->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 d8551c9d5b6c..a01a38332dc1 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);
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index becfc8b725de..a86ce9cb3547 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -265,6 +265,21 @@ struct iommu_dirty_ops {
struct iommu_dirty_bitmap *dirty);
};

+/**
+ * struct iommu_user_data - iommu driver specific user space data info
+ * @type: The data type of the user buffer
+ * @uptr: Pointer to the user buffer for copy_from_user()
+ * @len: The length of the user buffer in bytes
+ *
+ * A user space data is an uAPI that is defined in include/uapi/linux/iommufd.h
+ * @type, @uptr and @len should be just copied from an iommufd core uAPI struct.
+ */
+struct iommu_user_data {
+ unsigned int type;
+ void __user *uptr;
+ size_t len;
+};
+
/**
* struct iommu_ops - iommu ops and capabilities
* @capable: check capability
@@ -279,8 +294,12 @@ struct iommu_dirty_ops {
* parameters as defined in include/uapi/linux/iommufd.h.
* Unlike @domain_alloc, it is called only by IOMMUFD and
* must fully initialize the new domain before return.
- * Upon success, a domain is returned. Upon failure,
- * ERR_PTR must be returned.
+ * Upon success, if the @user_data is valid and the @parent
+ * points to a kernel-managed domain, the new domain must be
+ * IOMMU_DOMAIN_NESTED type; otherwise, the @parent must be
+ * NULL while the @user_data can be optionally provided, the
+ * new domain must support __IOMMU_DOMAIN_PAGING.
+ * Upon failure, ERR_PTR must be returned.
* @probe_device: Add device to iommu driver handling
* @release_device: Remove device from iommu driver handling
* @probe_finalize: Do final setup work after the device is added to an IOMMU
@@ -313,7 +332,9 @@ struct iommu_ops {

/* Domain allocation and freeing by the iommu driver */
struct iommu_domain *(*domain_alloc)(unsigned iommu_domain_type);
- struct iommu_domain *(*domain_alloc_user)(struct device *dev, u32 flags);
+ struct iommu_domain *(*domain_alloc_user)(struct device *dev, u32 flags,
+ struct iommu_domain *parent,
+ const struct iommu_user_data *user_data);

struct iommu_device *(*probe_device)(struct device *dev);
void (*release_device)(struct device *dev);
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index c44eecf5d318..fccc6315a520 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -361,6 +361,14 @@ enum iommufd_hwpt_alloc_flags {
IOMMU_HWPT_ALLOC_DIRTY_TRACKING = 1 << 1,
};

+/**
+ * enum iommu_hwpt_data_type - IOMMU HWPT Data Type
+ * @IOMMU_HWPT_DATA_NONE: no data
+ */
+enum iommu_hwpt_data_type {
+ IOMMU_HWPT_DATA_NONE,
+};
+
/**
* struct iommu_hwpt_alloc - ioctl(IOMMU_HWPT_ALLOC)
* @size: sizeof(struct iommu_hwpt_alloc)
--
2.34.1