scsi: clarify sense codes for LUN0 emulation

The LUN0 emulation is just that, an emulation for a non-existing
LUN0. So we should be returning LUN_NOT_SUPPORTED for any request
coming from any other LUN.
And we should be aborting unhandled commands with INVALID OPCODE,
not LUN NOT SUPPORTED.
Signed-off-by: NHannes Reinecke <hare@suse.com>
Message-Id: <1501835795-92331-4-git-send-email-hare@suse.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

hw/scsi/scsi-bus.c

@@ -517,6 +517,11 @@ static int32_t scsi_target_send_command(SCSIRequest *req, uint8_t *buf)
 {
     SCSITargetReq *r = DO_UPCAST(SCSITargetReq, req, req);
 
+    if (req->lun != 0) {
+        scsi_req_build_sense(req, SENSE_CODE(LUN_NOT_SUPPORTED));
+        scsi_req_complete(req, CHECK_CONDITION);
+        return 0;
+    }
     switch (buf[0]) {
     case REPORT_LUNS:
         if (!scsi_target_emulate_report_luns(r)) {
@@ -542,7 +547,7 @@ static int32_t scsi_target_send_command(SCSIRequest *req, uint8_t *buf)
     case TEST_UNIT_READY:
         break;
     default:
-        scsi_req_build_sense(req, SENSE_CODE(LUN_NOT_SUPPORTED));
+        scsi_req_build_sense(req, SENSE_CODE(INVALID_OPCODE));
         scsi_req_complete(req, CHECK_CONDITION);
         return 0;
     illegal_request: