Re: [PATCH v2 2/2] acpi, gicv3-its, numa: Adding numa node mapping for gic-its units

[Lorenzo Pieralisi]

On Tue, Jun 20, 2017 at 10:47:24PM +0530, Ganapatrao Kulkarni wrote:
> Hi Lorenzo,
> 
> On Tue, Jun 20, 2017 at 8:47 PM, Lorenzo Pieralisi
> <lorenzo.pieralisi@xxxxxxx> wrote:
> > Hi Ganapatrao,
> >
> > On Tue, Jun 20, 2017 at 12:37:17PM +0530, Ganapatrao Kulkarni wrote:
> >> Add code to parse SRAT ITS Affinity sub table as defined in ACPI 6.2
> >> Later in per device probe, ITS devices are mapped to
> >> numa node using ITS id to proximity domain mapping.
> >>
> >> Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@xxxxxxxxxx>
> >> ---
> >>  drivers/irqchip/irq-gic-v3-its.c | 76 +++++++++++++++++++++++++++++++++++++++-
> >>  1 file changed, 75 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> >> index 45ea1933..5865a75 100644
> >> --- a/drivers/irqchip/irq-gic-v3-its.c
> >> +++ b/drivers/irqchip/irq-gic-v3-its.c
> >> @@ -1833,6 +1833,78 @@ static int __init its_of_probe(struct device_node *node)
> >>
> >>  #define ACPI_GICV3_ITS_MEM_SIZE (SZ_128K)
> >>
> >> +#ifdef CONFIG_ACPI_NUMA
> >> +struct its_srat_map {
> >> +     u32                     numa_node;  /* numa node id */
> >> +     u32                     its_id;  /* GIC ITS ID */
> >> +     struct list_head        entry;
> >> +};
> >> +
> >> +static LIST_HEAD(its_srat_maps);
> >> +
> >> +static int acpi_get_its_numa_node(u32 its_id)
> >> +{
> >> +     struct its_srat_map *srat_map;
> >> +
> >> +     list_for_each_entry(srat_map, &its_srat_maps, entry) {
> >> +             if (its_id == srat_map->its_id)
> >> +                     return srat_map->numa_node;
> >> +     }
> >> +     return NUMA_NO_NODE;
> >> +}
> >
> > I do not want to come across as pedantic and I understand that the API
> > to parse static ACPI tables sucks (ie in theory you could avoid stashing
> > nodes altogether and just use a global variable to parse an ITS ID at
> > a time but it sucks to go through the SRAT multiple times) but would not
> > it be easier to just declare an __initdata static array and counter and
> > be done with this ? We do not need this stuff after boot so I do not see
> > a point in keeping it in memory and in allocating the nodes dynamically.
> 
> yes, it was my initial thought (as done v1), and i have replaced to
> dynamic array in this series. I might have misunderstood your comments.
> if you have no objection for the static array of size MAX_NUMNODES
> as done v1 [1], i can send v3 with that change?
> 
> [1] https://patchwork.kernel.org/patch/9768869/
>
It is ok by me sorry for delaying you further.

> > Apologies if I was not clear in my comments to the previous set, I did
> > not like stashing ITS PXM values in arch/arm64 code but I understand you
> > need an array (__initdata) to avoid reading the SRAT multiple times.
> 
> yes, having static array to hold parsed table is required to avoid
> multiple iterations
> of parsing functions.
> This array can go in __initdata.

Agreed, thanks.

Lorenzo

> 
> >
> > Thanks,
> > Lorenzo
> >
> >> +
> >> +static int __init
> >> +gic_acpi_parse_srat_its(struct acpi_subtable_header *header,
> >> +                      const unsigned long end)
> >> +{
> >> +     int pxm, node;
> >> +     struct its_srat_map *srat_map;
> >> +     struct acpi_srat_its_affinity *its_affinity;
> >> +
> >> +     its_affinity = (struct acpi_srat_its_affinity *)header;
> >> +     if (!its_affinity)
> >> +             return -EINVAL;
> >> +
> >> +     if (its_affinity->header.length <
> >> +                     sizeof(struct acpi_srat_its_affinity)) {
> >> +             pr_err("SRAT:ITS: Invalid SRAT header length: %d\n",
> >> +                     its_affinity->header.length);
> >> +             return -EINVAL;
> >> +     }
> >> +
> >> +     pxm = its_affinity->proximity_domain;
> >> +     node = acpi_map_pxm_to_node(pxm);
> >> +
> >> +     if (node == NUMA_NO_NODE || node >= MAX_NUMNODES) {
> >> +             pr_err("SRAT:ITS Invalid numa node %d\n", node);
> >> +             return -EINVAL;
> >> +     }
> >> +
> >> +     srat_map = kzalloc(sizeof(*srat_map), GFP_KERNEL);
> >> +     if (!srat_map)
> >> +             return -ENOMEM;
> >> +
> >> +     srat_map->numa_node = node;
> >> +     srat_map->its_id = its_affinity->its_id;
> >> +     list_add(&srat_map->entry, &its_srat_maps);
> >> +     pr_info("ACPI: NUMA: SRAT: ITS: PXM %d -> ITS_ID %d -> NODE %d\n",
> >> +             srat_map->its_id, pxm, node);
> >> +
> >> +     return 0;
> >> +}
> >> +
> >> +static int __init acpi_table_parse_srat_its(void)
> >> +{
> >> +     return acpi_table_parse_entries(ACPI_SIG_SRAT,
> >> +                                     sizeof(struct acpi_table_srat),
> >> +                                     ACPI_SRAT_TYPE_GIC_ITS_AFFINITY,
> >> +                                     gic_acpi_parse_srat_its, 0);
> >> +}
> >> +#else
> >> +#define acpi_table_parse_srat_its(void) { }
> >> +#define acpi_get_its_numa_node(its_id) NUMA_NO_NODE
> >> +#endif
> >> +
> >>  static int __init gic_acpi_parse_madt_its(struct acpi_subtable_header *header,
> >>                                         const unsigned long end)
> >>  {
> >> @@ -1861,7 +1933,8 @@ static int __init gic_acpi_parse_madt_its(struct acpi_subtable_header *header,
> >>               goto dom_err;
> >>       }
> >>
> >> -     err = its_probe_one(&res, dom_handle, NUMA_NO_NODE);
> >> +     err = its_probe_one(&res, dom_handle,
> >> +                     acpi_get_its_numa_node(its_entry->translation_id));
> >>       if (!err)
> >>               return 0;
> >>
> >> @@ -1873,6 +1946,7 @@ static int __init gic_acpi_parse_madt_its(struct acpi_subtable_header *header,
> >>
> >>  static void __init its_acpi_probe(void)
> >>  {
> >> +     acpi_table_parse_srat_its();
> >>       acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
> >>                             gic_acpi_parse_madt_its, 0);
> >>  }
> >> --
> >> 1.8.1.4
> >>
> 
> thanks
> Ganapat