From 9fab8e1fe15014a4bd147eeedd2491bcfbba4e59 Mon Sep 17 00:00:00 2001

From: Paolo Bonzini <pbonzini@redhat.com>

Date: Mon, 29 Jul 2013 14:27:39 +0200

Subject: [PATCH] exec: fix writing to MMIO area with non-power-of-two length

The problem is introduced by commit 2332616 (exec: Support 64-bit

operations in address_space_rw, 2013-07-08).  Before that commit,

memory_access_size would only return 1/2/4.

Since alignment is already handled above, reduce l to the largest

power of two that is smaller than l.

Cc: qemu-stable@nongnu.org

Reported-by: Oleksii Shevchuk <alxchk@gmail.com>

Tested-by: Oleksii Shevchuk <alxchk@gmail.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

(cherry picked from commit 098178f2749a63fbbb1a626dcc7d939d5cb2bde7)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

---

 exec.c | 3 +++

 1 file changed, 3 insertions(+)

diff --git a/exec.c b/exec.c

index 3ca9381..394f7e2 100644

--- a/exec.c

+++ b/exec.c

@@ -1928,6 +1928,9 @@ static int memory_access_size(MemoryRegion *mr, unsigned l, hwaddr addr)

     if (l > access_size_max) {

         l = access_size_max;

     }

+    if (l & (l - 1)) {

+        l = 1 << (qemu_fls(l) - 1);

+    }

     return l;

 }