scsi: ignore LUN field in the CDB

The LUN field in the CDB is a historical relic.  Ignore it as reserved,
which is what modern SCSI specifications actually say.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

hw/scsi-disk.c

@@ -518,7 +518,7 @@ static int scsi_disk_emulate_inquiry(SCSIRequest *req, uint8_t *outbuf)
 
     memset(outbuf, 0, buflen);
 
-    if (req->lun || req->cmd.buf[1] >> 5) {
+    if (req->lun) {
         outbuf[0] = 0x7f;	/* LUN not supported */
         return buflen;
     }
@@ -1024,9 +1024,9 @@ static int32_t scsi_send_command(SCSIRequest *req, uint8_t *buf)
     }
 #endif
 
-    if (req->lun || buf[1] >> 5) {
+    if (req->lun) {
         /* Only LUN 0 supported.  */
-        DPRINTF("Unimplemented LUN %d\n", req->lun ? req->lun : buf[1] >> 5);
+        DPRINTF("Unimplemented LUN %d\n", req->lun);
         if (command != REQUEST_SENSE && command != INQUIRY) {
             scsi_command_complete(r, CHECK_CONDITION,
                                   SENSE_CODE(LUN_NOT_SUPPORTED));

hw/scsi-generic.c

@@ -337,9 +337,8 @@ static int32_t scsi_send_command(SCSIRequest *req, uint8_t *cmd)
     SCSIGenericReq *r = DO_UPCAST(SCSIGenericReq, req, req);
     int ret;
 
-    if (cmd[0] != REQUEST_SENSE &&
-        (req->lun != s->lun || (cmd[1] >> 5) != s->lun)) {
-        DPRINTF("Unimplemented LUN %d\n", req->lun ? req->lun : cmd[1] >> 5);
+    if (cmd[0] != REQUEST_SENSE && req->lun != s->lun) {
+        DPRINTF("Unimplemented LUN %d\n", req->lun);
         scsi_set_sense(s, SENSE_CODE(LUN_NOT_SUPPORTED));
         r->req.status = CHECK_CONDITION;
         scsi_req_complete(&r->req);