Re: [PATCH] xen/arm: Reduce redundant clear root pages when teardown p2m

[Julien Grall <julien@xxxxxxx>]

On 12/12/2022 11:27, Henry Wang wrote:
> Hi Julien,
Hi,

> > -----Original Message-----
> > From: Julien Grall <julien@xxxxxxx>
> > Subject: Re: [PATCH] xen/arm: Reduce redundant clear root pages when
> > teardown p2m
> >
> > Hi Henry,
> >
> > >        PROGRESS(p2m):
> > > +        /*
> > > +         * We are about to free the intermediate page-tables, so clear the
> > > +         * root to prevent any walk to use them.
> > > +         */
> > > +        p2m_clear_root_pages(&d->arch.p2m);
> > The commit message suggests this should only be called once. However,
> > you will still end up to call p2m_clear_root_pages() multiple time if
> > p2m_teardown() is preempted.
> Thanks for confirming this, would adding another PROGRESS stage
> such as PROGRESS(p2m_clean) before PROGRESS(p2m) seem ok to you?
The would be fine with me.

Cheers,

--
Julien Grall