Re: [PATCH v5 1/2] xen/domain: introduce common hardware emulation flags

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 5 Jun 2025, Jan Beulich wrote:
> On 05.06.2025 03:17, dmkhn@xxxxxxxxx wrote:
> > On Wed, Jun 04, 2025 at 12:36:17PM +0200, Jan Beulich wrote:
> >> On 02.06.2025 21:17, dmkhn@xxxxxxxxx wrote:
> >>> From: Denis Mukhin <dmukhin@xxxxxxxx>
> >>>
> >>> Add common emulation_flags for configuring domain emulation features.
> >>>
> >>> Print d->emulation_flags from 'q' keyhandler for better traceability while
> >>> debugging.
> >>>
> >>> Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
> >>> Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> >>
> >> It's not becoming clear why this would want doing, nor in how far some of
> >> the bits there may gain "common" meaning, too. Imo this kind of change is
> >> meaningful only in a series where later the common-ness is also used.
> > 
> > I have a set of upcoming changes here:
> >   
> > https://gitlab.com/xen-project/people/dmukhin/xen/-/tree/vuart-framework?ref_type=heads
> > 
> > Specifically,
> >  
> > https://gitlab.com/xen-project/people/dmukhin/xen/-/commit/17f44d23c1904374963c4ec839bc8219041b5d26
> > 
> > enables the use of emulation_flags on Arm.
> > 
> > I can move this patch to the upcoming series, if needed, but looks like it 
> > is
> > OK to have it for Arm even now.
> 
> Prior to that series making it to a ready-to-be-committed state, it'll be
> (effectively) dead code on Arm. Which strictly speaking Misra objects to.
> I wonder if you, Stefano, considered that when giving your R-b.

We have not been enforcing the "no dead code" rule (R2.2) especially on
a per patch basis. In general in my view, it is better to reduce dead
code rather than increase dead code, but it is OK to do so temporarily.