add new system file

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2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/drivers/xen/grant-table.c
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@@ -33,7 +33,7 @@
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33
 
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 #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
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35
 
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-#include <linux/bootmem.h>
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+#include <linux/memblock.h>
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 #include <linux/sched.h>
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 #include <linux/mm.h>
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 #include <linux/slab.h>
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@@ -64,7 +64,6 @@
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 #include <asm/xen/hypercall.h>
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 #include <asm/xen/interface.h>
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-#include <asm/pgtable.h>
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 #include <asm/sync_bitops.h>
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 /* External tools reserve first few grant table entries. */
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@@ -135,12 +134,9 @@
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 	 */
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 	unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
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 	/*
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-	 * Query the status of a grant entry. Ref parameter is reference of
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-	 * queried grant entry, return value is the status of queried entry.
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-	 * Detailed status(writing/reading) can be gotten from the return value
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-	 * by bit operations.
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+	 * Read the frame number related to a given grant reference.
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 	 */
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-	int (*query_foreign_access)(grant_ref_t ref);
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+	unsigned long (*read_frame)(grant_ref_t ref);
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 };
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 struct unmap_refs_callback_data {
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@@ -285,22 +281,6 @@
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 }
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 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
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-static int gnttab_query_foreign_access_v1(grant_ref_t ref)
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-{
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-	return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
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-}
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-
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-static int gnttab_query_foreign_access_v2(grant_ref_t ref)
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-{
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-	return grstatus[ref] & (GTF_reading|GTF_writing);
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-}
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-
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-int gnttab_query_foreign_access(grant_ref_t ref)
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-{
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-	return gnttab_interface->query_foreign_access(ref);
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-}
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-EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
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-
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 static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
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 {
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 	u16 flags, nflags;
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@@ -354,6 +334,16 @@
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 }
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 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
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+static unsigned long gnttab_read_frame_v1(grant_ref_t ref)
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+{
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+	return gnttab_shared.v1[ref].frame;
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+}
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+
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+static unsigned long gnttab_read_frame_v2(grant_ref_t ref)
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+{
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+	return gnttab_shared.v2[ref].full_page.frame;
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+}
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+
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 struct deferred_entry {
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 	struct list_head list;
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 	grant_ref_t ref;
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@@ -383,12 +373,9 @@
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 		spin_unlock_irqrestore(&gnttab_list_lock, flags);
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 		if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
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 			put_free_entry(entry->ref);
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-			if (entry->page) {
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-				pr_debug("freeing g.e. %#x (pfn %#lx)\n",
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-					 entry->ref, page_to_pfn(entry->page));
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-				put_page(entry->page);
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-			} else
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-				pr_info("freeing g.e. %#x\n", entry->ref);
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+			pr_debug("freeing g.e. %#x (pfn %#lx)\n",
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+				 entry->ref, page_to_pfn(entry->page));
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+			put_page(entry->page);
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 			kfree(entry);
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 			entry = NULL;
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 		} else {
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@@ -413,8 +400,17 @@
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 static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
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 				struct page *page)
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 {
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-	struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
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+	struct deferred_entry *entry;
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+	gfp_t gfp = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
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 	const char *what = KERN_WARNING "leaking";
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+
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+	entry = kmalloc(sizeof(*entry), gfp);
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+	if (!page) {
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+		unsigned long gfn = gnttab_interface->read_frame(ref);
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+
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+		page = pfn_to_page(gfn_to_pfn(gfn));
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+		get_page(page);
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+	}
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 	if (entry) {
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 		unsigned long flags;
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@@ -436,11 +432,21 @@
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 	       what, ref, page ? page_to_pfn(page) : -1);
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 }
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+int gnttab_try_end_foreign_access(grant_ref_t ref)
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+{
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+	int ret = _gnttab_end_foreign_access_ref(ref, 0);
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+
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+	if (ret)
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+		put_free_entry(ref);
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+
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+	return ret;
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+}
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+EXPORT_SYMBOL_GPL(gnttab_try_end_foreign_access);
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+
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 void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
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 			       unsigned long page)
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 {
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-	if (gnttab_end_foreign_access_ref(ref, readonly)) {
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-		put_free_entry(ref);
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+	if (gnttab_try_end_foreign_access(ref)) {
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 		if (page != 0)
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 			put_page(virt_to_page(page));
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 	} else
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@@ -664,7 +670,6 @@
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 	unsigned int nr_glist_frames, new_nr_glist_frames;
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 	unsigned int grefs_per_frame;
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-	BUG_ON(gnttab_interface == NULL);
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 	grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
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 	new_nr_grant_frames = nr_grant_frames + more_frames;
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@@ -803,7 +808,7 @@
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 {
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 	int ret;
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-	ret = alloc_xenballooned_pages(nr_pages, pages);
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+	ret = xen_alloc_unpopulated_pages(nr_pages, pages);
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 	if (ret < 0)
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 		return ret;
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@@ -814,6 +819,129 @@
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 	return ret;
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 }
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 EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
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+
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+#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
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+static inline void cache_init(struct gnttab_page_cache *cache)
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+{
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+	cache->pages = NULL;
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+}
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+
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+static inline bool cache_empty(struct gnttab_page_cache *cache)
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+{
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+	return !cache->pages;
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+}
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+
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+static inline struct page *cache_deq(struct gnttab_page_cache *cache)
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+{
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+	struct page *page;
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+
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+	page = cache->pages;
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+	cache->pages = page->zone_device_data;
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+
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+	return page;
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+}
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+
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+static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
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+{
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+	page->zone_device_data = cache->pages;
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+	cache->pages = page;
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+}
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+#else
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+static inline void cache_init(struct gnttab_page_cache *cache)
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+{
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+	INIT_LIST_HEAD(&cache->pages);
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+}
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+
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+static inline bool cache_empty(struct gnttab_page_cache *cache)
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+{
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+	return list_empty(&cache->pages);
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+}
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+
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+static inline struct page *cache_deq(struct gnttab_page_cache *cache)
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+{
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+	struct page *page;
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+
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+	page = list_first_entry(&cache->pages, struct page, lru);
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+	list_del(&page->lru);
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+
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+	return page;
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+}
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+
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+static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
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+{
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+	list_add(&page->lru, &cache->pages);
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+}
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+#endif
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+
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+void gnttab_page_cache_init(struct gnttab_page_cache *cache)
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+{
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+	spin_lock_init(&cache->lock);
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+	cache_init(cache);
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+	cache->num_pages = 0;
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+}
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+EXPORT_SYMBOL_GPL(gnttab_page_cache_init);
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+
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+int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page)
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+{
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+	unsigned long flags;
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+
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+	spin_lock_irqsave(&cache->lock, flags);
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+
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+	if (cache_empty(cache)) {
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+		spin_unlock_irqrestore(&cache->lock, flags);
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+		return gnttab_alloc_pages(1, page);
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+	}
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+
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+	page[0] = cache_deq(cache);
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+	cache->num_pages--;
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+
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+	spin_unlock_irqrestore(&cache->lock, flags);
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+
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+	return 0;
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+}
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+EXPORT_SYMBOL_GPL(gnttab_page_cache_get);
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+
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+void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
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+			   unsigned int num)
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+{
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+	unsigned long flags;
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+	unsigned int i;
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+
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+	spin_lock_irqsave(&cache->lock, flags);
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+
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+	for (i = 0; i < num; i++)
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+		cache_enq(cache, page[i]);
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+	cache->num_pages += num;
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+
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+	spin_unlock_irqrestore(&cache->lock, flags);
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+}
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+EXPORT_SYMBOL_GPL(gnttab_page_cache_put);
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+
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+void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, unsigned int num)
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+{
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+	struct page *page[10];
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+	unsigned int i = 0;
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+	unsigned long flags;
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+
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+	spin_lock_irqsave(&cache->lock, flags);
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+
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+	while (cache->num_pages > num) {
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+		page[i] = cache_deq(cache);
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+		cache->num_pages--;
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+		if (++i == ARRAY_SIZE(page)) {
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+			spin_unlock_irqrestore(&cache->lock, flags);
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+			gnttab_free_pages(i, page);
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+			i = 0;
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+			spin_lock_irqsave(&cache->lock, flags);
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+		}
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+	}
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+
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+	spin_unlock_irqrestore(&cache->lock, flags);
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+
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+	if (i != 0)
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+		gnttab_free_pages(i, page);
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+}
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+EXPORT_SYMBOL_GPL(gnttab_page_cache_shrink);
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 void gnttab_pages_clear_private(int nr_pages, struct page **pages)
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 {
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@@ -838,7 +966,7 @@
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 void gnttab_free_pages(int nr_pages, struct page **pages)
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 {
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 	gnttab_pages_clear_private(nr_pages, pages);
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-	free_xenballooned_pages(nr_pages, pages);
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+	xen_free_unpopulated_pages(nr_pages, pages);
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 }
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 EXPORT_SYMBOL_GPL(gnttab_free_pages);
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@@ -852,6 +980,9 @@
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 	unsigned long pfn, start_pfn;
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 	size_t size;
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 	int i, ret;
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+
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+	if (args->nr_pages < 0 || args->nr_pages > (INT_MAX >> PAGE_SHIFT))
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+		return -ENOMEM;
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 	size = args->nr_pages << PAGE_SHIFT;
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 	if (args->coherent)
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@@ -1160,7 +1291,6 @@
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 static unsigned int nr_status_frames(unsigned int nr_grant_frames)
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 {
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-	BUG_ON(gnttab_interface == NULL);
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 	return gnttab_frames(nr_grant_frames, SPP);
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 }
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@@ -1297,7 +1427,7 @@
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 	.update_entry			= gnttab_update_entry_v1,
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 	.end_foreign_access_ref		= gnttab_end_foreign_access_ref_v1,
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 	.end_foreign_transfer_ref	= gnttab_end_foreign_transfer_ref_v1,
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-	.query_foreign_access		= gnttab_query_foreign_access_v1,
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+	.read_frame			= gnttab_read_frame_v1,
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 };
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 static const struct gnttab_ops gnttab_v2_ops = {
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@@ -1309,7 +1439,7 @@
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 	.update_entry			= gnttab_update_entry_v2,
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 	.end_foreign_access_ref		= gnttab_end_foreign_access_ref_v2,
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 	.end_foreign_transfer_ref	= gnttab_end_foreign_transfer_ref_v2,
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-	.query_foreign_access		= gnttab_query_foreign_access_v2,
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+	.read_frame			= gnttab_read_frame_v2,
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 };
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 static bool gnttab_need_v2(void)
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@@ -1363,8 +1493,7 @@
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 	if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
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 		gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
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 		if (gnttab_shared.addr == NULL) {
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-			pr_warn("gnttab share frames (addr=0x%08lx) is not mapped!\n",
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-				(unsigned long)xen_auto_xlat_grant_frames.vaddr);
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+			pr_warn("gnttab share frames is not mapped!\n");
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 			return -ENOMEM;
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 		}
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 	}
..
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@@ -1389,7 +1518,6 @@
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1518
 	int rc;
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1519
 	unsigned int cur, extra;
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1520
 
1392
-	BUG_ON(gnttab_interface == NULL);
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 	cur = nr_grant_frames;
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 	extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
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 		 gnttab_interface->grefs_per_grant_frame);
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@@ -1424,7 +1552,6 @@
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 	/* Determine the maximum number of frames required for the
1425
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 	 * grant reference free list on the current hypervisor.
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 	 */
1427
-	BUG_ON(gnttab_interface == NULL);
1428
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 	max_nr_glist_frames = (max_nr_grant_frames *
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 			       gnttab_interface->grefs_per_grant_frame / RPP);
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1557