RE: [PATCH for-4.14] x86/shim: Fix defconfig selection and trim the build further

[Paul Durrant <xadimgnik@xxxxxxxxx>]

> -----Original Message-----
> From: Jan Beulich <jbeulich@xxxxxxxx>
> Sent: 04 June 2020 07:43
> To: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Cc: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>; Wei Liu <wl@xxxxxxx>; Roger 
> Pau Monné
> <roger.pau@xxxxxxxxxx>; Juergen Gross <jgross@xxxxxxxx>; Paul Durrant 
> <paul@xxxxxxx>; Dario Faggioli
> <dfaggioli@xxxxxxxx>
> Subject: Re: [PATCH for-4.14] x86/shim: Fix defconfig selection and trim the 
> build further
> 
> On 03.06.2020 19:09, Andrew Cooper wrote:
> > Several options (TBOOT, XENOPROF, Scheduler) depend on EXPERT to be able to
> > deselect/configure.
> >
> > Enabling EXPERT now causes the request of the Credit1 scheduler to be 
> > honoured
> > (rather than giving us Credit2), but take this opportunity to switch to 
> > Null,
> > as the previously problematic issues are now believed to be fixed.
> >
> > Enabling EXPERT also allows XEN_SHSTK to be selected, and we don't want this
> > being built for shim.  We also don't want TRACEBUFFER or GDBSX either.
> >
> > Take this oppotunity to swap the disable of HVM_FEP for a general disable of
> > HVM (likely to have wider impliciations in the future), and disable ARGO 
> > (will
> > necesserily need plumbing work to function in shim).
> 
> Odd. I was quite sure this is the case already; in particular my
> own build test of a shim config has this already.
> 
> > Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> 
> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Release-acked-by: Paul Durrant <paul@xxxxxxx>

> 
> I have a question though (without implying the patch here needs
> adjusting, but rather with a look towards after 4.14):
> 
> > --- a/xen/arch/x86/configs/pvshim_defconfig
> > +++ b/xen/arch/x86/configs/pvshim_defconfig
> > @@ -5,19 +5,25 @@ CONFIG_PVH_GUEST=y
> >  CONFIG_PV_SHIM=y
> >  CONFIG_PV_SHIM_EXCLUSIVE=y
> >  CONFIG_NR_CPUS=32
> > +CONFIG_EXPERT=y
> > +CONFIG_SCHED_NULL=y
> >  # Disable features not used by the PV shim
> > +# CONFIG_HVM is not set
> > +# CONFIG_XEN_SHSTK is not set
> >  # CONFIG_HYPFS is not set
> >  # CONFIG_SHADOW_PAGING is not set
> >  # CONFIG_BIGMEM is not set
> > -# CONFIG_HVM_FEP is not set
> >  # CONFIG_TBOOT is not set
> >  # CONFIG_KEXEC is not set
> >  # CONFIG_XENOPROF is not set
> >  # CONFIG_XSM is not set
> > +# CONFIG_ARGO is not set
> > +# CONFIG_SCHED_CREDIT is not set
> >  # CONFIG_SCHED_CREDIT2 is not set
> >  # CONFIG_SCHED_RTDS is not set
> >  # CONFIG_SCHED_ARINC653 is not set
> > -# CONFIG_SCHED_NULL is not set
> >  # CONFIG_LIVEPATCH is not set
> >  # CONFIG_SUPPRESS_DUPLICATE_SYMBOL_WARNINGS is not set
> > +# CONFIG_TRACEBUFFER is not set
> >  # CONFIG_DEBUG is not set
> > +# CONFIG_GDBSX is not set
> 
> I assume both the "enable" and "disable" sections here are ordered
> like they would be in a resulting full .config. But this being two
> separate sections, doing so doesn't help e.g. diff-ing. How about
> we sort both sections alphabetically (short of other good sorting
> criteria, yet better than entirely unsorted)?
> 
> Jan