[Xen-devel] [PATCH] xen/arm: map_dev_mmio_region: The iomem permission check should be done on MFN

[Julien Grall <julien.grall@xxxxxxx>]

The helper iomem_access_permitted expects MFNs in parameters and not
GNFs. Thankfully only the hardware domain can call this function and
it will always be with GFNS == MFNs for now.

Also, fix the printf to use the MFN range and not the GFN one.

Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
Cc: Shannon Zhao <shannon.zhao@xxxxxxxxxx>

---
    This patch is a good candidate to backport to Xen 4.7. Without
    it, the hardware domain can map any MMIO because the permission
    check is done on the GPFNs and not the MNFs.
---
 xen/arch/arm/p2m.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 6a19c57..4c6547d 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -1275,14 +1275,14 @@ int map_dev_mmio_region(struct domain *d,
 {
     int res;
 
-    if ( !(nr && iomem_access_permitted(d, start_gfn, start_gfn + nr - 1)) )
+    if ( !(nr && iomem_access_permitted(d, mfn, mfn + nr - 1)) )
         return 0;
 
     res = map_mmio_regions(d, start_gfn, nr, mfn);
     if ( res < 0 )
     {
         printk(XENLOG_G_ERR "Unable to map [%#lx - %#lx] in Dom%d\n",
-               start_gfn, start_gfn + nr - 1, d->domain_id);
+               mfn, mfn + nr - 1, d->domain_id);
         return res;
     }
 
-- 
1.9.1


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