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

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 11 Aug 2021, 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>
> +#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);

Given that this is not actually a warning (is it?) then I would move it
to XENLOG_INFO


> +    if ( nid >= MAX_NUMNODES )
> +    {
> +        printk(XENLOG_WARNING "Node id %u exceeds maximum value\n", nid);

This could be XENLOG_ERR


> +        return -EINVAL;
> +    }
> +
> +    return dtb_numa_processor_affinity_init(nid);
> +}