ivshmem: fix number of bytes to push to fifo

If the fifo has 0 bytes, and the read is of size 1, the call to
fifo8_push_all() will copy off boundary data.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Claudio Fontana <claudio.fontana@huawei.com>

diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index fb53b3f..2162d02 100644 (file)
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -455,7 +455,7 @@ static void ivshmem_read(void *opaque, const uint8_t *buf, int size)
         uint32_t num;
 
         IVSHMEM_DPRINTF("short read of %d bytes\n", size);
-        num = MAX(size, sizeof(long) - fifo8_num_used(&s->incoming_fifo));
+        num = MIN(size, sizeof(long) - fifo8_num_used(&s->incoming_fifo));
         fifo8_push_all(&s->incoming_fifo, buf, num);
         if (fifo8_num_used(&s->incoming_fifo) < sizeof(incoming_posn)) {
             return;