Re: [PATCH v2 2/4] xen/arm: its: separate ITS and host LPI quirk scopes

[Mykola Kvach <mykola_kvach@xxxxxxxx>]

Hi Michal,

Thanks for the follow-up.

On Fri, Jul 31, 2026 at 10:24:47AM +0200, Orzel, Michal wrote:
> 
> 
> On 28-May-26 02:25, Mykola Kvach wrote:
> > From: Mykola Kvach <mykola_kvach@xxxxxxxx>
> > 
> > ITS quirks can impose restrictions on memory accessed by the ITS itself and
> > on shared host LPI/Redistributor state. These scopes are not identical, so
> > a single global ITS quirk state makes the host LPI policy depend implicitly
> > on the quirks seen while initializing host ITSes.
> > 
> > Add per-ITS quirk_flags to struct host_its and keep a separate
> > host_lpi_flags state in the LPI code. The quirk table now records the
> > ITS-private and host LPI scopes explicitly through its_flags and lpi_flags.
> > The R-Car Gen4 quirk applies the same memory-related restrictions to both
> > scopes, preserving the existing behavior without relying on an implicit
> > aggregation step.
> > 
> > This also removes the old assumption that all host ITSes must expose the
> > same quirk state. Host LPI restrictions are accumulated only from quirk
> > entries that explicitly set lpi_flags.
> > 
> > Use per-ITS quirk_flags for GITS_CBASER, GITS_BASER<n> and ITT allocations.
> > Use host_lpi_flags directly in gic-v3-lpi.c for GICR_PROPBASER and
> > GICR_PENDBASER setup. Memory-related quirk bits are named GICV3_QUIRK_MEM_*
> > and are translated by shared gicv3_mem_get_*() helpers.
> > 
> > Signed-off-by: Mykola Kvach <mykola_kvach@xxxxxxxx>
> I already gave R-b for this patch but noticed two issues:
> 
> [...]
> 
> >  
> > -static void gicv3_its_enable_quirks(struct host_its *hw_its)
> > +static void __init gicv3_its_collect_quirks(struct host_its *hw_its)
> The only caller of gicv3_its_collect_quirks() is
> gicv3_its_init_single_its(), which stays non-init until patch 4/4.
> Please annotate the caller here as well.

I plan to replace the first patch, whose release fix is now upstream,
with the initialization-order follow-up discussed with Julien. It will
prepare all ITSes and collect their quirks, initialize host LPI state,
and then activate the ITSes.

I'll put the __init annotations on the ITS preparation and activation
functions, and gicv3_its_init(), in that replacement patch. This will
make the quirk collector's caller init-only before the quirk-scope
changes are introduced.

> 
> [...]
> 
> > @@ -157,6 +164,7 @@ int gicv3_lpi_init_rdist(void __iomem * rdist_base);
> >  /* Initialize the host structures for LPIs and the host ITSes. */
> >  int gicv3_lpi_init_host_lpis(unsigned int host_lpi_bits);
> >  int gicv3_its_init(void);
> > +void __init gicv3_lpi_update_host_flags(uint32_t flags);
> Please, do not add __init here for a prototype.

I'll also remove __init from the gicv3_lpi_update_host_flags() prototype
and keep it on the definition.

Best regards,
Mykola