Re: [PATCH v1 1/2] domctl: Handle XEN_DOMCTL_getpageframeinfo3 without the domctl lock

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

On Thu, Jun 11, 2026 at 09:11:15AM -0400, Daniel P. Smith wrote:
> On 6/9/26 11:15 AM, Ross Lagerwall wrote:
> > It does not have side effects and is protected from concurrent changes
> > by the P2M read lock therefore skip taking the domctl lock.
> > 
> > Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
> > ---
> >   xen/arch/x86/domctl.c | 4 ++++
> >   xen/common/domctl.c   | 1 +
> >   2 files changed, 5 insertions(+)
> > 
> > diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
> > index 83bf51e498df..0e9a2532887e 100644
> > --- a/xen/arch/x86/domctl.c
> > +++ b/xen/arch/x86/domctl.c
> > @@ -301,6 +301,10 @@ long arch_do_domctl(
> >           /* Games to allow this code block to handle a compat guest. */
> >           void __user *guest_handle = domctl->u.getpageframeinfo3.array.p;
> > +        ret = xsm_domctl(XSM_OTHER, d, domctl);
> > +        if ( ret )
> > +            break;
> > +
> >           if ( unlikely(num > 1024) ||
> >                unlikely(num != domctl->u.getpageframeinfo3.num) )
> >           {
> > diff --git a/xen/common/domctl.c b/xen/common/domctl.c
> > index 3efa5b9d55b9..35144d95b808 100644
> > --- a/xen/common/domctl.c
> > +++ b/xen/common/domctl.c
> > @@ -555,6 +555,7 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
> >       case XEN_DOMCTL_gsi_permission:
> >       case XEN_DOMCTL_bind_pt_irq:
> >       case XEN_DOMCTL_unbind_pt_irq:
> > +    case XEN_DOMCTL_getpageframeinfo3:
> >           ret = arch_do_domctl(op, d, u_domctl);
> >           goto domctl_out_unlock_domonly;
> I would respectfully ask to be mindful when XSM hooks are being manipulated
> in a patch that a review from an XSM maintainer should be sought before
> committing a patch. In this case case the change itself is good, though I
> would have liked the opportunity to comment that the commit message should
> have had some explanation on the xsm change.

I've already replied to 2/2, but would like to re-instate my apology
here so it doesn't seem like this went unnoticed:

Sorry, this was already picked up in a rush to get it into 4.22 and I
didn't realize it was missing an XSM maintainer Ack.  That's entirely
my fault, there was no intention to bypass or overrule your opinion.

Regards, Roger.