1 files changed, 148 insertions, 0 deletions
diff --git a/drivers/iommu/iommu-pages.h b/drivers/iommu/iommu-pages.h
new file mode 100644
index 000000000000..ae9da4f571f6
--- /dev/null
+++ b/drivers/iommu/iommu-pages.h
@@ -0,0 +1,148 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2024, Google LLC.
+ * Pasha Tatashin <pasha.tatashin@soleen.com>
+ */
+
+#ifndef __IOMMU_PAGES_H
+#define __IOMMU_PAGES_H
+
+#include <linux/iommu.h>
+
+/**
+ * struct ioptdesc - Memory descriptor for IOMMU page tables
+ * @iopt_freelist_elm: List element for a struct iommu_pages_list
+ *
+ * This struct overlays struct page for now. Do not modify without a good
+ * understanding of the issues.
+ */
+struct ioptdesc {
+	unsigned long __page_flags;
+
+	struct list_head iopt_freelist_elm;
+	unsigned long __page_mapping;
+	union {
+		u8 incoherent;
+		pgoff_t __index;
+	};
+	void *_private;
+
+	unsigned int __page_type;
+	atomic_t __page_refcount;
+#ifdef CONFIG_MEMCG
+	unsigned long memcg_data;
+#endif
+};
+
+static inline struct ioptdesc *folio_ioptdesc(struct folio *folio)
+{
+	return (struct ioptdesc *)folio;
+}
+
+static inline struct folio *ioptdesc_folio(struct ioptdesc *iopt)
+{
+	return (struct folio *)iopt;
+}
+
+static inline struct ioptdesc *virt_to_ioptdesc(void *virt)
+{
+	return folio_ioptdesc(virt_to_folio(virt));
+}
+
+void *iommu_alloc_pages_node_sz(int nid, gfp_t gfp, size_t size);
+void iommu_free_pages(void *virt);
+void iommu_put_pages_list(struct iommu_pages_list *list);
+
+/**
+ * iommu_pages_list_add - add the page to a iommu_pages_list
+ * @list: List to add the page to
+ * @virt: Address returned from iommu_alloc_pages_node_sz()
+ */
+static inline void iommu_pages_list_add(struct iommu_pages_list *list,
+					void *virt)
+{
+	list_add_tail(&virt_to_ioptdesc(virt)->iopt_freelist_elm, &list->pages);
+}
+
+/**
+ * iommu_pages_list_splice - Put all the pages in list from into list to
+ * @from: Source list of pages
+ * @to: Destination list of pages
+ *
+ * from must be re-initialized after calling this function if it is to be
+ * used again.
+ */
+static inline void iommu_pages_list_splice(struct iommu_pages_list *from,
+					   struct iommu_pages_list *to)
+{
+	list_splice(&from->pages, &to->pages);
+}
+
+/**
+ * iommu_pages_list_empty - True if the list is empty
+ * @list: List to check
+ */
+static inline bool iommu_pages_list_empty(struct iommu_pages_list *list)
+{
+	return list_empty(&list->pages);
+}
+
+/**
+ * iommu_alloc_pages_sz - Allocate a zeroed page of a given size from
+ *                          specific NUMA node
+ * @nid: memory NUMA node id
+ * @gfp: buddy allocator flags
+ * @size: Memory size to allocate, this is rounded up to a power of 2
+ *
+ * Returns the virtual address of the allocated page.
+ */
+static inline void *iommu_alloc_pages_sz(gfp_t gfp, size_t size)
+{
+	return iommu_alloc_pages_node_sz(NUMA_NO_NODE, gfp, size);
+}
+
+int iommu_pages_start_incoherent(void *virt, struct device *dma_dev);
+int iommu_pages_start_incoherent_list(struct iommu_pages_list *list,
+				      struct device *dma_dev);
+
+#ifdef CONFIG_X86
+#define IOMMU_PAGES_USE_DMA_API 0
+#include <linux/cacheflush.h>
+
+static inline void iommu_pages_flush_incoherent(struct device *dma_dev,
+						void *virt, size_t offset,
+						size_t len)
+{
+	clflush_cache_range(virt + offset, len);
+}
+static inline void
+iommu_pages_stop_incoherent_list(struct iommu_pages_list *list,
+				 struct device *dma_dev)
+{
+	/*
+	 * For performance leave the incoherent flag alone which turns this into
+	 * a NOP. For X86 the rest of the stop/free flow ignores the flag.
+	 */
+}
+static inline void iommu_pages_free_incoherent(void *virt,
+					       struct device *dma_dev)
+{
+	iommu_free_pages(virt);
+}
+#else
+#define IOMMU_PAGES_USE_DMA_API 1
+#include <linux/dma-mapping.h>
+
+static inline void iommu_pages_flush_incoherent(struct device *dma_dev,
+						void *virt, size_t offset,
+						size_t len)
+{
+	dma_sync_single_for_device(dma_dev, (uintptr_t)virt + offset, len,
+				   DMA_TO_DEVICE);
+}
+void iommu_pages_stop_incoherent_list(struct iommu_pages_list *list,
+				      struct device *dma_dev);
+void iommu_pages_free_incoherent(void *virt, struct device *dma_dev);
+#endif
+
+#endif /* __IOMMU_PAGES_H */