1 files changed, 60 insertions, 1 deletions

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index bcaf797216d1..9694a1a8b2e2 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -37,6 +37,7 @@
 #include <xen/xen.h>
 #include <xen/grant_table.h>
 #include <xen/gntdev.h>
+#include <xen/events.h>
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
 #include <asm/xen/page.h>
@@ -63,6 +64,13 @@ struct gntdev_priv {
         struct mmu_notifier mn;
 };
 
+struct unmap_notify {
+        int flags;
+        /* Address relative to the start of the grant_map */
+        int addr;
+        int event;
+};
+
 struct grant_map {
         struct list_head next;
         struct vm_area_struct *vma;
@@ -71,6 +79,7 @@ struct grant_map {
         int flags;
         int is_mapped;
         atomic_t users;
+        struct unmap_notify notify;
         struct ioctl_gntdev_grant_ref *grants;
         struct gnttab_map_grant_ref   *map_ops;
         struct gnttab_unmap_grant_ref *unmap_ops;
@@ -165,7 +174,7 @@ static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
         list_for_each_entry(map, &priv->maps, next) {
                 if (map->index != index)
                         continue;
-                if (map->count != count)
+                if (count && map->count != count)
                         continue;
                 return map;
         }
@@ -184,6 +193,10 @@ static void gntdev_put_map(struct grant_map *map)
 
         atomic_sub(map->count, &pages_mapped);
 
+        if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
+                notify_remote_via_evtchn(map->notify.event);
+        }
+
         if (map->pages) {
                 if (!use_ptemod)
                         unmap_grant_pages(map, 0, map->count);
@@ -274,6 +287,16 @@ static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
 {
         int i, err = 0;
 
+        if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
+                int pgno = (map->notify.addr >> PAGE_SHIFT);
+                if (pgno >= offset && pgno < offset + pages) {
+                        uint8_t *tmp = kmap(map->pages[pgno]);
+                        tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
+                        kunmap(map->pages[pgno]);
+                        map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
+                }
+        }
+
         pr_debug("map %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
         err = gnttab_unmap_refs(map->unmap_ops + offset, map->pages, pages);
         if (err)
@@ -519,6 +542,39 @@ static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
         return 0;
 }
 
+static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
+{
+        struct ioctl_gntdev_unmap_notify op;
+        struct grant_map *map;
+        int rc;
+
+        if (copy_from_user(&op, u, sizeof(op)))
+                return -EFAULT;
+
+        if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT))
+                return -EINVAL;
+
+        spin_lock(&priv->lock);
+
+        list_for_each_entry(map, &priv->maps, next) {
+                uint64_t begin = map->index << PAGE_SHIFT;
+                uint64_t end = (map->index + map->count) << PAGE_SHIFT;
+                if (op.index >= begin && op.index < end)
+                        goto found;
+        }
+        rc = -ENOENT;
+        goto unlock_out;
+
+ found:
+        map->notify.flags = op.action;
+        map->notify.addr = op.index - (map->index << PAGE_SHIFT);
+        map->notify.event = op.event_channel_port;
+        rc = 0;
+ unlock_out:
+        spin_unlock(&priv->lock);
+        return rc;
+}
+
 static long gntdev_ioctl(struct file *flip,
                          unsigned int cmd, unsigned long arg)
 {
@@ -535,6 +591,9 @@ static long gntdev_ioctl(struct file *flip,
         case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
                 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);
 
+        case IOCTL_GNTDEV_SET_UNMAP_NOTIFY:
+                return gntdev_ioctl_notify(priv, ptr);
+
         default:
                 pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
                 return -ENOIOCTLCMD;