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>

6 files changed, 46 insertions, 101 deletions

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 787e1bb5aafc..3e276eb23d1b 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/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.
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 8009acbe41e4..696c694986d0 100644
--- a/arch/x86/xen/p2m.c
+++ b/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;
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 875025f299b6..6620b73d0490 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/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);
         }
 
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 34a2704fbc88..073b4a19a8b0 100644
--- a/drivers/xen/gntdev.c
+++ b/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;
 
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 8ee13e2e45e2..b84e3ab839aa 100644
--- a/drivers/xen/grant-table.c
+++ b/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);
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 7ad033dbc845..a5af2a26d94f 100644
--- a/include/xen/grant_table.h
+++ b/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