Re: [PATCH] x86/pod: fix decrease_reservation() clearing of M2P entries

["Roger Pau Monné" <roger.pau@citrix.com>]

On Wed, Dec 10, 2025 at 11:07:00AM +0100, Jan Beulich wrote:
> On 10.12.2025 10:35, Roger Pau Monne wrote:
> > Add the missing index increase in the M2P clearing loop, otherwise the loop
> > keeps pointlessly setting the same MFN entry repeatedly.  This seems to be
> > an oversight from the change that introduced support to process high order
> > pages in one go.
> 
> Ouch.
> 
> > Fixes: 3c352011c0d3 ("x86/PoD: shorten certain operations on higher order ranges")
> > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> 
> Reviewed-by: Jan Beulich <jbeulich@suse.com>
> 
> I'd like to note that things were broken in the same way before that commit,
> too, simply because the order wasn't taken into account all. (This is not a
> request to change the Fixes: tag, though. It's just an observation.)

Are you sure?  Previous to that commit the order is not taken into
account, and each 4K page is processed independently: the `i` index is
strictly increased with +1 for each loop.

Thanks, Roger.