Revert "xen/grant-table: Avoid m2p_override during mapping"

This reverts commit 08ece5bb2312b4510b161a6ef6682f37f4eac8a1.

As it breaks ARM builds and needs more attention
on the ARM side.

Acked-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/x86/include/asm/xen/page.h

@@ -52,8 +52,7 @@ extern unsigned long set_phys_range_identity(unsigned long pfn_s,
 extern int m2p_add_override(unsigned long mfn, struct page *page,
 			    struct gnttab_map_grant_ref *kmap_op);
 extern int m2p_remove_override(struct page *page,
-			       struct gnttab_map_grant_ref *kmap_op,
-			       unsigned long mfn);
+				struct gnttab_map_grant_ref *kmap_op);
 extern struct page *m2p_find_override(unsigned long mfn);
 extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
 
@@ -122,7 +121,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
 		pfn = m2p_find_override_pfn(mfn, ~0);
 	}
 
-	/*
+	/* 
 	 * pfn is ~0 if there are no entries in the m2p for mfn or if the
 	 * entry doesn't map back to the mfn and m2p_override doesn't have a
 	 * valid entry for it.

arch/x86/xen/p2m.c

@@ -899,6 +899,13 @@ int m2p_add_override(unsigned long mfn, struct page *page,
 					"m2p_add_override: pfn %lx not mapped", pfn))
 			return -EINVAL;
 	}
+	WARN_ON(PagePrivate(page));
+	SetPagePrivate(page);
+	set_page_private(page, mfn);
+	page->index = pfn_to_mfn(pfn);
+
+	if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
+		return -ENOMEM;
 
 	if (kmap_op != NULL) {
 		if (!PageHighMem(page)) {
@@ -937,16 +944,19 @@ int m2p_add_override(unsigned long mfn, struct page *page,
 }
 EXPORT_SYMBOL_GPL(m2p_add_override);
 int m2p_remove_override(struct page *page,
-			struct gnttab_map_grant_ref *kmap_op,
-			unsigned long mfn)
+		struct gnttab_map_grant_ref *kmap_op)
 {
 	unsigned long flags;
+	unsigned long mfn;
 	unsigned long pfn;
 	unsigned long uninitialized_var(address);
 	unsigned level;
 	pte_t *ptep = NULL;
 
 	pfn = page_to_pfn(page);
+	mfn = get_phys_to_machine(pfn);
+	if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT))
+		return -EINVAL;
 
 	if (!PageHighMem(page)) {
 		address = (unsigned long)__va(pfn << PAGE_SHIFT);
@@ -960,7 +970,10 @@ int m2p_remove_override(struct page *page,
 	spin_lock_irqsave(&m2p_override_lock, flags);
 	list_del(&page->lru);
 	spin_unlock_irqrestore(&m2p_override_lock, flags);
+	WARN_ON(!PagePrivate(page));
+	ClearPagePrivate(page);
 
+	set_phys_to_machine(pfn, page->index);
 	if (kmap_op != NULL) {
 		if (!PageHighMem(page)) {
 			struct multicall_space mcs;

drivers/block/xen-blkback/blkback.c

@@ -285,7 +285,8 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root,
 
 		if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST ||
 			!rb_next(&persistent_gnt->node)) {
-			ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
+			ret = gnttab_unmap_refs(unmap, NULL, pages,
+				segs_to_unmap);
 			BUG_ON(ret);
 			put_free_pages(blkif, pages, segs_to_unmap);
 			segs_to_unmap = 0;
@@ -320,7 +321,8 @@ static void unmap_purged_grants(struct work_struct *work)
 		pages[segs_to_unmap] = persistent_gnt->page;
 
 		if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
-			ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
+			ret = gnttab_unmap_refs(unmap, NULL, pages,
+				segs_to_unmap);
 			BUG_ON(ret);
 			put_free_pages(blkif, pages, segs_to_unmap);
 			segs_to_unmap = 0;
@@ -328,7 +330,7 @@ static void unmap_purged_grants(struct work_struct *work)
 		kfree(persistent_gnt);
 	}
 	if (segs_to_unmap > 0) {
-		ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
+		ret = gnttab_unmap_refs(unmap, NULL, pages, segs_to_unmap);
 		BUG_ON(ret);
 		put_free_pages(blkif, pages, segs_to_unmap);
 	}
@@ -668,14 +670,15 @@ static void xen_blkbk_unmap(struct xen_blkif *blkif,
 				    GNTMAP_host_map, pages[i]->handle);
 		pages[i]->handle = BLKBACK_INVALID_HANDLE;
 		if (++invcount == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
-			ret = gnttab_unmap_refs(unmap, unmap_pages, invcount);
+			ret = gnttab_unmap_refs(unmap, NULL, unmap_pages,
+			                        invcount);
 			BUG_ON(ret);
 			put_free_pages(blkif, unmap_pages, invcount);
 			invcount = 0;
 		}
 	}
 	if (invcount) {
-		ret = gnttab_unmap_refs(unmap, unmap_pages, invcount);
+		ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount);
 		BUG_ON(ret);
 		put_free_pages(blkif, unmap_pages, invcount);
 	}
@@ -737,7 +740,7 @@ again:
 	}
 
 	if (segs_to_map) {
-		ret = gnttab_map_refs(map, pages_to_gnt, segs_to_map);
+		ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map);
 		BUG_ON(ret);
 	}
 

drivers/xen/gntdev.c

@@ -284,10 +284,8 @@ static int map_grant_pages(struct grant_map *map)
 	}
 
 	pr_debug("map %d+%d\n", map->index, map->count);
-	err = gnttab_map_refs_userspace(map->map_ops,
-					use_ptemod ? map->kmap_ops : NULL,
-					map->pages,
-					map->count);
+	err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
+			map->pages, map->count);
 	if (err)
 		return err;
 
@@ -317,10 +315,9 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
 		}
 	}
 
-	err = gnttab_unmap_refs_userspace(map->unmap_ops + offset,
-					  use_ptemod ? map->kmap_ops + offset : NULL,
-					  map->pages + offset,
-					  pages);
+	err = gnttab_unmap_refs(map->unmap_ops + offset,
+			use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset,
+			pages);
 	if (err)
 		return err;
 

drivers/xen/grant-table.c

@@ -928,17 +928,15 @@ void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
 }
 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
 
-int __gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
+int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
 		    struct gnttab_map_grant_ref *kmap_ops,
-		    struct page **pages, unsigned int count,
-		    bool m2p_override)
+		    struct page **pages, unsigned int count)
 {
 	int i, ret;
 	bool lazy = false;
 	pte_t *pte;
-	unsigned long mfn, pfn;
+	unsigned long mfn;
 
-	BUG_ON(kmap_ops && !m2p_override);
 	ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
 	if (ret)
 		return ret;
@@ -957,12 +955,10 @@ int __gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
 			set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT,
 					map_ops[i].dev_bus_addr >> PAGE_SHIFT);
 		}
-		return 0;
+		return ret;
 	}
 
-	if (m2p_override &&
-	    !in_interrupt() &&
-	    paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
+	if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
 		arch_enter_lazy_mmu_mode();
 		lazy = true;
 	}
@@ -979,20 +975,8 @@ int __gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
 		} else {
 			mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
 		}
-		pfn = page_to_pfn(pages[i]);
-
-		WARN_ON(PagePrivate(pages[i]));
-		SetPagePrivate(pages[i]);
-		set_page_private(pages[i], mfn);
-
-		pages[i]->index = pfn_to_mfn(pfn);
-		if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {
-			ret = -ENOMEM;
-			goto out;
-		}
-		if (m2p_override)
-			ret = m2p_add_override(mfn, pages[i], kmap_ops ?
-					       &kmap_ops[i] : NULL);
+		ret = m2p_add_override(mfn, pages[i], kmap_ops ?
+				       &kmap_ops[i] : NULL);
 		if (ret)
 			goto out;
 	}
@@ -1003,32 +987,15 @@ int __gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
 
 	return ret;
 }
-
-int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
-		    struct page **pages, unsigned int count)
-{
-	return __gnttab_map_refs(map_ops, NULL, pages, count, false);
-}
 EXPORT_SYMBOL_GPL(gnttab_map_refs);
 
-int gnttab_map_refs_userspace(struct gnttab_map_grant_ref *map_ops,
-			      struct gnttab_map_grant_ref *kmap_ops,
-			      struct page **pages, unsigned int count)
-{
-	return __gnttab_map_refs(map_ops, kmap_ops, pages, count, true);
-}
-EXPORT_SYMBOL_GPL(gnttab_map_refs_userspace);
-
-int __gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
+int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
 		      struct gnttab_map_grant_ref *kmap_ops,
-		      struct page **pages, unsigned int count,
-		      bool m2p_override)
+		      struct page **pages, unsigned int count)
 {
 	int i, ret;
 	bool lazy = false;
-	unsigned long pfn, mfn;
 
-	BUG_ON(kmap_ops && !m2p_override);
 	ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
 	if (ret)
 		return ret;
@@ -1039,33 +1006,17 @@ int __gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
 			set_phys_to_machine(unmap_ops[i].host_addr >> PAGE_SHIFT,
 					INVALID_P2M_ENTRY);
 		}
-		return 0;
+		return ret;
 	}
 
-	if (m2p_override &&
-	    !in_interrupt() &&
-	    paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
+	if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
 		arch_enter_lazy_mmu_mode();
 		lazy = true;
 	}
 
 	for (i = 0; i < count; i++) {
-		pfn = page_to_pfn(pages[i]);
-		mfn = get_phys_to_machine(pfn);
-		if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) {
-			ret = -EINVAL;
-			goto out;
-		}
-
-		set_page_private(pages[i], INVALID_P2M_ENTRY);
-		WARN_ON(!PagePrivate(pages[i]));
-		ClearPagePrivate(pages[i]);
-		set_phys_to_machine(pfn, pages[i]->index);
-		if (m2p_override)
-			ret = m2p_remove_override(pages[i],
-						  kmap_ops ?
-						   &kmap_ops[i] : NULL,
-						  mfn);
+		ret = m2p_remove_override(pages[i], kmap_ops ?
+				       &kmap_ops[i] : NULL);
 		if (ret)
 			goto out;
 	}
@@ -1076,22 +1027,8 @@ int __gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
 
 	return ret;
 }
-
-int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *map_ops,
-		    struct page **pages, unsigned int count)
-{
-	return __gnttab_unmap_refs(map_ops, NULL, pages, count, false);
-}
 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
 
-int gnttab_unmap_refs_userspace(struct gnttab_unmap_grant_ref *map_ops,
-				struct gnttab_map_grant_ref *kmap_ops,
-				struct page **pages, unsigned int count)
-{
-	return __gnttab_unmap_refs(map_ops, kmap_ops, pages, count, true);
-}
-EXPORT_SYMBOL_GPL(gnttab_unmap_refs_userspace);
-
 static unsigned nr_status_frames(unsigned nr_grant_frames)
 {
 	BUG_ON(grefs_per_grant_frame == 0);

include/xen/grant_table.h

@@ -191,15 +191,11 @@ void gnttab_free_auto_xlat_frames(void);
 #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
 
 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
+		    struct gnttab_map_grant_ref *kmap_ops,
 		    struct page **pages, unsigned int count);
-int gnttab_map_refs_userspace(struct gnttab_map_grant_ref *map_ops,
-			      struct gnttab_map_grant_ref *kmap_ops,
-			      struct page **pages, unsigned int count);
 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
+		      struct gnttab_map_grant_ref *kunmap_ops,
 		      struct page **pages, unsigned int count);
-int gnttab_unmap_refs_userspace(struct gnttab_unmap_grant_ref *unmap_ops,
-				struct gnttab_map_grant_ref *kunmap_ops,
-				struct page **pages, unsigned int count);
 
 /* Perform a batch of grant map/copy operations. Retry every batch slot
  * for which the hypervisor returns GNTST_eagain. This is typically due