s390-virtio: Check for NULL device in reset hypercall

s390_virtio_bus_find_mem() may return a NULL VirtIOS390Device.
If called with, e.g., args[0] == 0, this leads to a segfault.
Fix this by adding error handling as done for other hypercalls.

Present since baf0b55a9e57b909b1f8b0f732c0b10242867418 (Implement
virtio reset).

Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/hw/s390x/s390-virtio.c b/hw/s390x/s390-virtio.c
index a8a489dc3ec026add3a8272f308f66d3fc5fdd92..2a1d9ac2daabdc2813b217916ef8eb41f256dba1 100644 (file)
--- a/hw/s390x/s390-virtio.c
+++ b/hw/s390x/s390-virtio.c
@@ -86,6 +86,9 @@ static int s390_virtio_hcall_reset(const uint64_t *args)
     VirtIOS390Device *dev;
 
     dev = s390_virtio_bus_find_mem(s390_bus, mem);
+    if (dev == NULL) {
+        return -EINVAL;
+    }
     virtio_reset(dev->vdev);
     stb_phys(dev->dev_offs + VIRTIO_DEV_OFFS_STATUS, 0);
     s390_virtio_device_sync(dev);