viostor: Fix MessageId update in MESSAGENUMBER_TO_QUEUE()

In the case that StorPortGetStartIoPerfParams() returns an optimal
MessageNumber that is higher than the MessageNumber of the existing
queues, MESSAGENUMBER_TO_QUEUE() tries to wrap around and assign queues
in a round-robin fashion. While it does this correctly for QueueNumber,
it fails to update MessageId correctly.

The correct relation is MessageId = QueueNumber + 1, and this has to be
ensured after limiting QueueNumber, too. The existing MessageId += 1
will make MessageId only more out of bounds for the array accesses it is
used for amongst others in VioStorCompleteRequest() and VioStorVQLock/
Unlock().

This code path is hard to hit because normally, the MessageNumber
returned by StorPortGetStartIoPerfParams() is limited to num_queues + 1
through the STOR_PERF_INTERRUPT_MESSAGE_RANGES feature. However, when I
modified VirtIoHwInitialize() to not enable this feature, I got instant
BSODs without this fix on a setup with 10 vcpus and virtio-blk
configured with num-queues=2,vectors=10.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Author: kevmw

viostor/virtio_stor_hw_helper.c

@@ -53,7 +53,7 @@
             if (QueueNumber >= adaptExt->num_queues)                                                                   \
             {                                                                                                          \
                 QueueNumber %= adaptExt->num_queues;                                                                   \
-                MessageId += 1;                                                                                        \
+                MessageId = QueueNumber + 1;                                                                           \
             }                                                                                                          \
         }                                                                                                              \
     }