[xen staging] tools/libxengnttab: correct size of allocated memory

[patchbot@xxxxxxx]

commit aad20e538d7ba0e36f5ed8d2bebb74096e3a6d7f
Author:     Juergen Gross <jgross@xxxxxxxx>
AuthorDate: Wed May 20 10:35:01 2020 +0200
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Thu Jun 11 17:13:20 2020 +0100

    tools/libxengnttab: correct size of allocated memory
    
    The size of the memory allocated for the IOCTL_GNTDEV_MAP_GRANT_REF
    ioctl() parameters is calculated wrong, which results in too much
    memory allocated.
    
    Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
    Reviewed-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
    Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Release-acked-by: Paul Durrant <paul@xxxxxxx>
---
 tools/libs/gnttab/freebsd.c | 2 +-
 tools/libs/gnttab/linux.c   | 8 +++-----
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/tools/libs/gnttab/freebsd.c b/tools/libs/gnttab/freebsd.c
index 886b588303..0588501d0f 100644
--- a/tools/libs/gnttab/freebsd.c
+++ b/tools/libs/gnttab/freebsd.c
@@ -74,7 +74,7 @@ void *osdep_gnttab_grant_map(xengnttab_handle *xgt,
     void *addr = NULL;
     int domids_stride;
     unsigned int refs_size = ROUNDUP(count *
-                                     sizeof(struct ioctl_gntdev_map_grant_ref),
+                                     sizeof(struct ioctl_gntdev_grant_ref),
                                      PAGE_SHIFT);
 
     domids_stride = (flags & XENGNTTAB_GRANT_MAP_SINGLE_DOMAIN) ? 0 : 1;
diff --git a/tools/libs/gnttab/linux.c b/tools/libs/gnttab/linux.c
index a01bb6c698..74331a4c7b 100644
--- a/tools/libs/gnttab/linux.c
+++ b/tools/libs/gnttab/linux.c
@@ -91,9 +91,7 @@ void *osdep_gnttab_grant_map(xengnttab_handle *xgt,
 {
     int fd = xgt->fd;
     struct ioctl_gntdev_map_grant_ref *map;
-    unsigned int map_size = ROUNDUP((sizeof(*map) + (count - 1) *
-                                    sizeof(struct ioctl_gntdev_map_grant_ref)),
-                                    PAGE_SHIFT);
+    unsigned int map_size = sizeof(*map) + (count - 1) * sizeof(map->refs[0]);
     void *addr = NULL;
     int domids_stride = 1;
     int i;
@@ -102,10 +100,10 @@ void *osdep_gnttab_grant_map(xengnttab_handle *xgt,
         domids_stride = 0;
 
     if ( map_size <= PAGE_SIZE )
-        map = alloca(sizeof(*map) +
-                     (count - 1) * sizeof(struct ioctl_gntdev_map_grant_ref));
+        map = alloca(map_size);
     else
     {
+        map_size = ROUNDUP(map_size, PAGE_SHIFT);
         map = mmap(NULL, map_size, PROT_READ | PROT_WRITE,
                    MAP_PRIVATE | MAP_ANON | MAP_POPULATE, -1, 0);
         if ( map == MAP_FAILED )
--
generated by git-patchbot for /home/xen/git/xen.git#staging