Re: [XEN PATCH v5 7/8] x86/mm: add defensive return

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Mon, 29 Jul 2024, Stefano Stabellini wrote:
> On Mon, 29 Jul 2024, Federico Serafini wrote:
> > Add defensive return statement at the end of an unreachable
> > default case. Other than improve safety, this meets the requirements
> > to deviate a violation of MISRA C Rule 16.3: "An unconditional `break'
> > statement shall terminate every switch-clause".
> > 
> > Signed-off-by: Federico Serafini <federico.serafini@xxxxxxxxxxx>
> 
> Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> 
> > ---
> > No changes from v3 and v4, further feedback on this thread would be 
> > appreciated:
> > https://lists.xenproject.org/archives/html/xen-devel/2024-07/msg00474.html

Looking at the older threads, I looks like Jan suggested EACCES, I also
think it is marginally better. My R-b stands also for EACCES. Jan, I
think you should go ahead and fix on commit


> > ---
> >  xen/arch/x86/mm.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
> > index 95795567f2..8973e76dff 100644
> > --- a/xen/arch/x86/mm.c
> > +++ b/xen/arch/x86/mm.c
> > @@ -917,6 +917,7 @@ get_page_from_l1e(
> >                  return 0;
> >              default:
> >                  ASSERT_UNREACHABLE();
> > +                return -EPERM;
> >              }
> >          }
> >          else if ( l1f & _PAGE_RW )
> > -- 
> > 2.34.1
> > 
> > 
>