Re: [XEN RFC PATCH 22/40] xen/arm: introduce a helper to parse device tree processor node

[Julien Grall <julien@xxxxxxx>]

On 20/08/2021 03:23, Wei Chen wrote:
> Hi Julien,
Hi Wei,

> > -----Original Message-----
> > From: Julien Grall <julien@xxxxxxx>
> > Sent: 2021年8月20日 2:13
> > To: Wei Chen <Wei.Chen@xxxxxxx>; xen-devel@xxxxxxxxxxxxxxxxxxxx;
> > sstabellini@xxxxxxxxxx; jbeulich@xxxxxxxx
> > Cc: Bertrand Marquis <Bertrand.Marquis@xxxxxxx>
> > Subject: Re: [XEN RFC PATCH 22/40] xen/arm: introduce a helper to parse
> > device tree processor node
> >
> > Hi Wei,
> >
> > On 11/08/2021 11:24, Wei Chen wrote:
> > > Processor NUMA ID information is stored in device tree's processor
> > > node as "numa-node-id". We need a new helper to parse this ID from
> > > processor node. If we get this ID from processor node, this ID's
> > > validity still need to be checked. Once we got a invalid NUMA ID
> > > from any processor node, the device tree will be marked as NUMA
> > > information invalid.
> > >
> > > Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
> > > ---
> > >    xen/arch/arm/numa_device_tree.c | 41 +++++++++++++++++++++++++++++++--
> > >    1 file changed, 39 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/xen/arch/arm/numa_device_tree.c
> > b/xen/arch/arm/numa_device_tree.c
> > > index 1c74ad135d..37cc56acf3 100644
> > > --- a/xen/arch/arm/numa_device_tree.c
> > > +++ b/xen/arch/arm/numa_device_tree.c
> > > @@ -20,16 +20,53 @@
> > >    #include <xen/init.h>
> > >    #include <xen/nodemask.h>
> > >    #include <xen/numa.h>
> > > +#include <xen/device_tree.h>
> > Nothing in this file seems to depend on xen/device_tree.h. So why do you
> > need to include it?
> I remember that without this header file, device_tree_get_u32 in this patch
> will cause compiling failed.
I looked at the prototype of device_tree_get_u32() and I can't find how 
it depends on bits from device_tree.h. Can you paste the compilation error?
> > > +#include <asm/setup.h>
> > >
> > >    s8 device_tree_numa = 0;
> > > +static nodemask_t processor_nodes_parsed __initdata;
> > >
> > > -int srat_disabled(void)
> > > +static int srat_disabled(void)
> > >    {
> > >        return numa_off || device_tree_numa < 0;
> > >    }
> > >
> > > -void __init bad_srat(void)
> > > +static __init void bad_srat(void)
> > >    {
> > >        printk(KERN_ERR "DT: NUMA information is not used.\n");
> > >        device_tree_numa = -1;
> > >    }
> > > +
> > > +/* Callback for device tree processor affinity */
> > > +static int __init dtb_numa_processor_affinity_init(nodeid_t node)
> > > +{
> > > +    if ( srat_disabled() )
> > > +        return -EINVAL;
> > > +    else if ( node == NUMA_NO_NODE || node >= MAX_NUMNODES ) {
> > > +               bad_srat();
> > > +               return -EINVAL;
> > > +       }
> > > +
> > > +    node_set(node, processor_nodes_parsed);
> > > +
> > > +    device_tree_numa = 1;
> > > +    printk(KERN_INFO "DT: NUMA node %u processor parsed\n", node);
> > > +
> > > +    return 0;
> > > +}
> > > +
> > > +/* Parse CPU NUMA node info */
> > > +int __init device_tree_parse_numa_cpu_node(const void *fdt, int node)
> > > +{
> > > +    uint32_t nid;
> > > +
> > > +    nid = device_tree_get_u32(fdt, node, "numa-node-id", MAX_NUMNODES);
> > > +    printk(XENLOG_WARNING "CPU on NUMA node:%u\n", nid);
> > > +    if ( nid >= MAX_NUMNODES )
> > > +    {
> > > +        printk(XENLOG_WARNING "Node id %u exceeds maximum value\n",
> > nid);
> > > +        return -EINVAL;
> > > +    }
> > > +
> > > +    return dtb_numa_processor_affinity_init(nid);
> > > +}
> > --
> > Julien Grall
Cheers,

--
Julien Grall