libqos/ahci: allow nondata commands for ahci_io variants

These variants try to set a data offset, even if you don't specify one.
In the cases where the offset is zero and it's a nondata command, just
ignore the instruction.
Signed-off-by: NJohn Snow <jsnow@redhat.com>
Message-id: 1452282920-21550-7-git-send-email-jsnow@redhat.com

tests/ahci-test.c

@@ -1080,7 +1080,6 @@ static void test_flush_retry(void)
     AHCIQState *ahci;
     AHCICommand *cmd;
     uint8_t port;
-    const char *s;
 
     prepare_blkdebug_script(debug_path, "flush_to_disk");
     ahci = ahci_boot_and_enable("-drive file=blkdebug:%s:%s,if=none,id=drive0,"
@@ -1094,19 +1093,10 @@ static void test_flush_retry(void)
     /* Issue Flush Command and wait for error */
     port = ahci_port_select(ahci);
     ahci_port_clear(ahci, port);
-    cmd = ahci_command_create(CMD_FLUSH_CACHE);
-    ahci_command_commit(ahci, cmd, port);
-    ahci_command_issue_async(ahci, cmd);
-    qmp_eventwait("STOP");
 
-    /* Complete the command */
-    s = "{'execute':'cont' }";
-    qmp_async(s);
-    qmp_eventwait("RESUME");
-    ahci_command_wait(ahci, cmd);
-    ahci_command_verify(ahci, cmd);
+    cmd = ahci_guest_io_halt(ahci, port, CMD_FLUSH_CACHE, 0, 0, 0);
+    ahci_guest_io_resume(ahci, cmd);
 
-    ahci_command_free(cmd);
     ahci_shutdown(ahci);
 }
 

tests/libqos/ahci.c

@@ -842,6 +842,9 @@ void ahci_command_set_offset(AHCICommand *cmd, uint64_t lba_sect)
     if (cmd->props->atapi) {
         ahci_atapi_command_set_offset(cmd, lba_sect);
         return;
+    } else if (!cmd->props->data && !lba_sect) {
+        /* Not meaningful, ignore. */
+        return;
     } else if (cmd->props->lba28) {
         g_assert_cmphex(lba_sect, <=, 0xFFFFFFF);
     } else if (cmd->props->lba48 || cmd->props->ncq) {