1 files changed, 109 insertions, 30 deletions

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 6fefb09af7c3..7fcaf3180a5b 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -1,6 +1,9 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_MEMREMAP_H_
 #define _LINUX_MEMREMAP_H_
+
+#include <linux/mmzone.h>
+#include <linux/range.h>
 #include <linux/ioport.h>
 #include <linux/percpu-refcount.h>
 
@@ -16,7 +19,7 @@ struct device;
  * @alloc: track pages consumed, private to vmemmap_populate()
  */
 struct vmem_altmap {
-	const unsigned long base_pfn;
+	unsigned long base_pfn;
 	const unsigned long end_pfn;
 	const unsigned long reserve;
 	unsigned long free;
@@ -25,7 +28,7 @@ struct vmem_altmap {
 };
 
 /*
- * Specialize ZONE_DEVICE memory into multiple types each having differents
+ * Specialize ZONE_DEVICE memory into multiple types each has a different
  * usage.
  *
  * MEMORY_DEVICE_PRIVATE:
@@ -36,7 +39,14 @@ struct vmem_altmap {
  * must be treated as an opaque object, rather than a "normal" struct page.
  *
  * A more complete discussion of unaddressable memory may be found in
- * include/linux/hmm.h and Documentation/vm/hmm.rst.
+ * include/linux/hmm.h and Documentation/mm/hmm.rst.
+ *
+ * MEMORY_DEVICE_COHERENT:
+ * Device memory that is cache coherent from device and CPU point of view. This
+ * is used on platforms that have an advanced system bus (like CAPI or CXL). A
+ * driver can hotplug the device memory using ZONE_DEVICE and with that memory
+ * type. Any page of a process can be migrated to such memory. However no one
+ * should be allowed to pin such memory so that it can always be evicted.
  *
  * MEMORY_DEVICE_FS_DAX:
  * Host memory that has similar access semantics as System RAM i.e. DMA
@@ -46,11 +56,10 @@ struct vmem_altmap {
  * wakeup is used to coordinate physical address space management (ex:
  * fs truncate/hole punch) vs pinned pages (ex: device dma).
  *
- * MEMORY_DEVICE_DEVDAX:
+ * MEMORY_DEVICE_GENERIC:
  * Host memory that has similar access semantics as System RAM i.e. DMA
- * coherent and supports page pinning. In contrast to
- * MEMORY_DEVICE_FS_DAX, this memory is access via a device-dax
- * character device.
+ * coherent and supports page pinning. This is for example used by DAX devices
+ * that expose memory using a character device.
  *
  * MEMORY_DEVICE_PCI_P2PDMA:
  * Device memory residing in a PCI BAR intended for use with Peer-to-Peer
@@ -59,34 +68,37 @@ struct vmem_altmap {
 enum memory_type {
 	/* 0 is reserved to catch uninitialized type fields */
 	MEMORY_DEVICE_PRIVATE = 1,
+	MEMORY_DEVICE_COHERENT,
 	MEMORY_DEVICE_FS_DAX,
-	MEMORY_DEVICE_DEVDAX,
+	MEMORY_DEVICE_GENERIC,
 	MEMORY_DEVICE_PCI_P2PDMA,
 };
 
 struct dev_pagemap_ops {
 	/*
-	 * Called once the page refcount reaches 1.  (ZONE_DEVICE pages never
-	 * reach 0 refcount unless there is a refcount bug. This allows the
-	 * device driver to implement its own memory management.)
+	 * Called once the page refcount reaches 0.  The reference count will be
+	 * reset to one by the core code after the method is called to prepare
+	 * for handing out the page again.
 	 */
 	void (*page_free)(struct page *page);
 
 	/*
-	 * Transition the refcount in struct dev_pagemap to the dead state.
-	 */
-	void (*kill)(struct dev_pagemap *pgmap);
-
-	/*
-	 * Wait for refcount in struct dev_pagemap to be idle and reap it.
-	 */
-	void (*cleanup)(struct dev_pagemap *pgmap);
-
-	/*
 	 * Used for private (un-addressable) device memory only.  Must migrate
 	 * the page back to a CPU accessible page.
 	 */
 	vm_fault_t (*migrate_to_ram)(struct vm_fault *vmf);
+
+	/*
+	 * Handle the memory failure happens on a range of pfns.  Notify the
+	 * processes who are using these pfns, and try to recover the data on
+	 * them if necessary.  The mf_flags is finally passed to the recover
+	 * function through the whole notify routine.
+	 *
+	 * When this is not implemented, or it returns -EOPNOTSUPP, the caller
+	 * will fall back to a common handler called mf_generic_kill_procs().
+	 */
+	int (*memory_failure)(struct dev_pagemap *pgmap, unsigned long pfn,
+			      unsigned long nr_pages, int mf_flags);
 };
 
 #define PGMAP_ALTMAP_VALID	(1 << 0)
@@ -94,27 +106,44 @@ struct dev_pagemap_ops {
 /**
  * struct dev_pagemap - metadata for ZONE_DEVICE mappings
  * @altmap: pre-allocated/reserved memory for vmemmap allocations
- * @res: physical address range covered by @ref
  * @ref: reference count that pins the devm_memremap_pages() mapping
- * @internal_ref: internal reference if @ref is not provided by the caller
- * @done: completion for @internal_ref
- * @dev: host device of the mapping for debug
- * @data: private data pointer for page_free()
+ * @done: completion for @ref
  * @type: memory type: see MEMORY_* in memory_hotplug.h
  * @flags: PGMAP_* flags to specify defailed behavior
+ * @vmemmap_shift: structural definition of how the vmemmap page metadata
+ *      is populated, specifically the metadata page order.
+ *	A zero value (default) uses base pages as the vmemmap metadata
+ *	representation. A bigger value will set up compound struct pages
+ *	of the requested order value.
  * @ops: method table
+ * @owner: an opaque pointer identifying the entity that manages this
+ *	instance.  Used by various helpers to make sure that no
+ *	foreign ZONE_DEVICE memory is accessed.
+ * @nr_range: number of ranges to be mapped
+ * @range: range to be mapped when nr_range == 1
+ * @ranges: array of ranges to be mapped when nr_range > 1
  */
 struct dev_pagemap {
 	struct vmem_altmap altmap;
-	struct resource res;
-	struct percpu_ref *ref;
-	struct percpu_ref internal_ref;
+	struct percpu_ref ref;
 	struct completion done;
 	enum memory_type type;
 	unsigned int flags;
+	unsigned long vmemmap_shift;
 	const struct dev_pagemap_ops *ops;
+	void *owner;
+	int nr_range;
+	union {
+		struct range range;
+		struct range ranges[0];
+	};
 };
 
+static inline bool pgmap_has_memory_failure(struct dev_pagemap *pgmap)
+{
+	return pgmap->ops && pgmap->ops->memory_failure;
+}
+
 static inline struct vmem_altmap *pgmap_altmap(struct dev_pagemap *pgmap)
 {
 	if (pgmap->flags & PGMAP_ALTMAP_VALID)
@@ -122,16 +151,54 @@ static inline struct vmem_altmap *pgmap_altmap(struct dev_pagemap *pgmap)
 	return NULL;
 }
 
+static inline unsigned long pgmap_vmemmap_nr(struct dev_pagemap *pgmap)
+{
+	return 1 << pgmap->vmemmap_shift;
+}
+
+static inline bool is_device_private_page(const struct page *page)
+{
+	return IS_ENABLED(CONFIG_DEVICE_PRIVATE) &&
+		is_zone_device_page(page) &&
+		page->pgmap->type == MEMORY_DEVICE_PRIVATE;
+}
+
+static inline bool folio_is_device_private(const struct folio *folio)
+{
+	return is_device_private_page(&folio->page);
+}
+
+static inline bool is_pci_p2pdma_page(const struct page *page)
+{
+	return IS_ENABLED(CONFIG_PCI_P2PDMA) &&
+		is_zone_device_page(page) &&
+		page->pgmap->type == MEMORY_DEVICE_PCI_P2PDMA;
+}
+
+static inline bool is_device_coherent_page(const struct page *page)
+{
+	return is_zone_device_page(page) &&
+		page->pgmap->type == MEMORY_DEVICE_COHERENT;
+}
+
+static inline bool folio_is_device_coherent(const struct folio *folio)
+{
+	return is_device_coherent_page(&folio->page);
+}
+
 #ifdef CONFIG_ZONE_DEVICE
+void zone_device_page_init(struct page *page);
 void *memremap_pages(struct dev_pagemap *pgmap, int nid);
 void memunmap_pages(struct dev_pagemap *pgmap);
 void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap);
 void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap);
 struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
 		struct dev_pagemap *pgmap);
+bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn);
 
 unsigned long vmem_altmap_offset(struct vmem_altmap *altmap);
 void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns);
+unsigned long memremap_compat_align(void);
 #else
 static inline void *devm_memremap_pages(struct device *dev,
 		struct dev_pagemap *pgmap)
@@ -156,6 +223,11 @@ static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
 	return NULL;
 }
 
+static inline bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn)
+{
+	return false;
+}
+
 static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
 {
 	return 0;
@@ -165,11 +237,18 @@ static inline void vmem_altmap_free(struct vmem_altmap *altmap,
 		unsigned long nr_pfns)
 {
 }
+
+/* when memremap_pages() is disabled all archs can remap a single page */
+static inline unsigned long memremap_compat_align(void)
+{
+	return PAGE_SIZE;
+}
 #endif /* CONFIG_ZONE_DEVICE */
 
 static inline void put_dev_pagemap(struct dev_pagemap *pgmap)
 {
 	if (pgmap)
-		percpu_ref_put(pgmap->ref);
+		percpu_ref_put(&pgmap->ref);
 }
+
 #endif /* _LINUX_MEMREMAP_H_ */