1 files changed, 150 insertions, 0 deletions
diff --git a/include/linux/generic_pt/iommu.h b/include/linux/generic_pt/iommu.h
new file mode 100644
index 000000000000..defa96abc497
--- /dev/null
+++ b/include/linux/generic_pt/iommu.h
@@ -0,0 +1,150 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2024-2025, NVIDIA CORPORATION & AFFILIATES
+ */
+#ifndef __GENERIC_PT_IOMMU_H
+#define __GENERIC_PT_IOMMU_H
+
+#include <linux/generic_pt/common.h>
+#include <linux/iommu.h>
+#include <linux/mm_types.h>
+
+struct pt_iommu_ops;
+
+/**
+ * DOC: IOMMU Radix Page Table
+ *
+ * The IOMMU implementation of the Generic Page Table provides an ops struct
+ * that is useful to go with an iommu_domain to serve the DMA API, IOMMUFD and
+ * the generic map/unmap interface.
+ *
+ * This interface uses a caller provided locking approach. The caller must have
+ * a VA range lock concept that prevents concurrent threads from calling ops on
+ * the same VA. Generally the range lock must be at least as large as a single
+ * map call.
+ */
+
+/**
+ * struct pt_iommu - Base structure for IOMMU page tables
+ *
+ * The format-specific struct will include this as the first member.
+ */
+struct pt_iommu {
+	/**
+	 * @domain: The core IOMMU domain. The driver should use a union to
+	 * overlay this memory with its previously existing domain struct to
+	 * create an alias.
+	 */
+	struct iommu_domain domain;
+
+	/**
+	 * @ops: Function pointers to access the API
+	 */
+	const struct pt_iommu_ops *ops;
+
+	/**
+	 * @nid: Node ID to use for table memory allocations. The IOMMU driver
+	 * may want to set the NID to the device's NID, if there are multiple
+	 * table walkers.
+	 */
+	int nid;
+};
+
+/**
+ * struct pt_iommu_info - Details about the IOMMU page table
+ *
+ * Returned from pt_iommu_ops->get_info()
+ */
+struct pt_iommu_info {
+	/**
+	 * @pgsize_bitmap: A bitmask where each set bit indicates
+	 * a page size that can be natively stored in the page table.
+	 */
+	u64 pgsize_bitmap;
+};
+
+struct pt_iommu_ops {
+	/**
+	 * @get_info: Return the pt_iommu_info structure
+	 * @iommu_table: Table to query
+	 *
+	 * Return some basic static information about the page table.
+	 */
+	void (*get_info)(struct pt_iommu *iommu_table,
+			 struct pt_iommu_info *info);
+
+	/**
+	 * @deinit: Undo a format specific init operation
+	 * @iommu_table: Table to destroy
+	 *
+	 * Release all of the memory. The caller must have already removed the
+	 * table from all HW access and all caches.
+	 */
+	void (*deinit)(struct pt_iommu *iommu_table);
+};
+
+static inline void pt_iommu_deinit(struct pt_iommu *iommu_table)
+{
+	/*
+	 * It is safe to call pt_iommu_deinit() before an init, or if init
+	 * fails. The ops pointer will only become non-NULL if deinit needs to be
+	 * run.
+	 */
+	if (iommu_table->ops)
+		iommu_table->ops->deinit(iommu_table);
+}
+
+/**
+ * struct pt_iommu_cfg - Common configuration values for all formats
+ */
+struct pt_iommu_cfg {
+	/**
+	 * @features: Features required. Only these features will be turned on.
+	 * The feature list should reflect what the IOMMU HW is capable of.
+	 */
+	unsigned int features;
+	/**
+	 * @hw_max_vasz_lg2: Maximum VA the IOMMU HW can support. This will
+	 * imply the top level of the table.
+	 */
+	u8 hw_max_vasz_lg2;
+	/**
+	 * @hw_max_oasz_lg2: Maximum OA the IOMMU HW can support. The format
+	 * might select a lower maximum OA.
+	 */
+	u8 hw_max_oasz_lg2;
+};
+
+/* Generate the exported function signatures from iommu_pt.h */
+#define IOMMU_PROTOTYPES(fmt)                                             \
+	int pt_iommu_##fmt##_init(struct pt_iommu_##fmt *table,           \
+				  const struct pt_iommu_##fmt##_cfg *cfg, \
+				  gfp_t gfp);                             \
+	void pt_iommu_##fmt##_hw_info(struct pt_iommu_##fmt *table,       \
+				      struct pt_iommu_##fmt##_hw_info *info)
+#define IOMMU_FORMAT(fmt, member)       \
+	struct pt_iommu_##fmt {         \
+		struct pt_iommu iommu;  \
+		struct pt_##fmt member; \
+	};                              \
+	IOMMU_PROTOTYPES(fmt)
+
+/*
+ * The driver should setup its domain struct like
+ *	union {
+ *		struct iommu_domain domain;
+ *		struct pt_iommu_xxx xx;
+ *	};
+ * PT_IOMMU_CHECK_DOMAIN(struct mock_iommu_domain, xx.iommu, domain);
+ *
+ * Which creates an alias between driver_domain.domain and
+ * driver_domain.xx.iommu.domain. This is to avoid a mass rename of existing
+ * driver_domain.domain users.
+ */
+#define PT_IOMMU_CHECK_DOMAIN(s, pt_iommu_memb, domain_memb) \
+	static_assert(offsetof(s, pt_iommu_memb.domain) ==   \
+		      offsetof(s, domain_memb))
+
+#undef IOMMU_PROTOTYPES
+#undef IOMMU_FORMAT
+#endif