On 07/28/14 12:08, Andrew Cooper wrote:

On 28/07/14 16:59, Don Slutz wrote:

Based on:

commit 2fcb51bc7a4fcb7534265d7bb155c6ddf03952b8
Author: kfraser@localhost.localdomain <kfraser@localhost.localdomain>
Date:   Mon Jul 9 14:29:53 2007 +0100

    Also allow boolean cmdline params to be inverted in two other ways.

    Now, a standard boolean (e.g., watchdog) can be inverted in three
    ways:
     1. no-watchdog
     2. watchdog=no
     3. watchdog=off

    Stacked inversions cancel each other: no-watchdog=no turns on the
    watchdog.

bool_assert is needed to do stacked inversions with parse_bool.

Signed-off-by: Don Slutz <dslutz@verizon.com>

Why do we need to care about stacked inversions?

From xen-command-line.markdown:

"Explicitly specifying any value other than those listed above is undefined, as is stacking a no- prefix with an explicit value."

The command line:

no-console_timestamps dom0_mem=3G loglvl=all guest_loglvl=all com1=9600,8n1 console=com1 crashkernel=256M@256M no-console_timestamps=no

in 4.4 and before ends up with date style console_timestamps.  In xen 4.5 you get no console_timestamps. 

The simpler case of no-console_timestamps no longer works also.

   -Don Slutz