Re: [PATCH] arm/gicv3: Detect normal NC ITS command queues

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

Oleksii, can we have a release ack on this fix?

On Fri, 15 May 2026, Luca Fancellu wrote:
> Hi Mykola,
> 
> > On 15 May 2026, at 10:40, Mykola Kvach <xakep.amatop@xxxxxxxxx> wrote:
> > 
> > From: Mykola Kvach <mykola_kvach@xxxxxxxx>
> > 
> > GITS_CBASER.InnerCache uses the GIC BASER cacheability encoding.
> > Both 0b000 (Device-nGnRnE) and 0b001 (Normal Inner
> > Non-cacheable) describe non-cacheable accesses to the command queue.
> > 
> > its_map_cbaser() only checked whether the shifted field was zero,
> > so an ITS that reports Normal Inner Non-cacheable would not set
> > HOST_ITS_FLUSH_CMD_QUEUE. Decode the field before comparing it with
> > the unshifted enum value, matching the handling of ITS BASER tables
> > and GICR_PROPBASER.
> > 
> > Fixes: 8ed8d21373be ("ARM: GICv3 ITS: map ITS command buffer")
> > Signed-off-by: Mykola Kvach <mykola_kvach@xxxxxxxx>
> > ---
> > xen/arch/arm/gic-v3-its.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
> > index 9005ce8ce5..7560d46c6d 100644
> > --- a/xen/arch/arm/gic-v3-its.c
> > +++ b/xen/arch/arm/gic-v3-its.c
> > @@ -424,7 +424,8 @@ static void *its_map_cbaser(struct host_its *its)
> >      * If the command queue memory is mapped as uncached, we need to flush
> >      * it on every access.
> >      */
> > -    if ( !(reg & GITS_BASER_INNER_CACHEABILITY_MASK) )
> > +    if ( MASK_EXTR(reg, GITS_BASER_INNER_CACHEABILITY_MASK) <=
> > +         GIC_BASER_CACHE_nC )
> >     {
> >         its->flags |= HOST_ITS_FLUSH_CMD_QUEUE;
> >         printk(XENLOG_WARNING "using non-cacheable ITS command queue\n");
> > -- 
> > 2.43.0
> > 
> > 
> 
> Looks ok to me
> 
> Reviewed-by: Luca Fancellu <luca.fancellu@xxxxxxx>