[PATCH v2 21/24] xen/arm: Generate distance-map node for Dom0 Device Tree

[Hirokazu Takahashi <taka@xxxxxxxxxxxxx>]

Generate the 'distance-map' node within the Domain-0 Device Tree.
This ensures that distances are populated only for the specific NUMA
nodes assigned to Domain-0.
---
 xen/arch/arm/domain_build.c | 50 +++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 750c3d53c2..e71d6cb254 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -718,6 +718,51 @@ static int __init fdt_property_interrupts(const struct 
kernel_info *kinfo,
     return res;
 }
 
+#ifdef CONFIG_NUMA
+static int __init make_distance_map_node(const struct domain *d, void *fdt)
+{
+    nodeid_t from, to;
+    unsigned int count = 0;
+    int res;
+
+    static uint32_t __initdata matrix[MAX_NUMNODES * MAX_NUMNODES * 3];
+
+    if ( nodes_weight(d->node_affinity) <= 1 )
+        return 0;
+
+    for_each_node_mask(from, d->node_affinity)
+    {
+        for_each_node_mask(to, d->node_affinity)
+        {
+            matrix[count * 3 + 0] = cpu_to_fdt32(from);
+            matrix[count * 3 + 1] = cpu_to_fdt32(to);
+            matrix[count * 3 + 2] = cpu_to_fdt32(__node_distance(from, to));
+            count++;
+        }
+    }
+
+    res = fdt_begin_node(fdt, "distance-map");
+    if ( res )
+        return res;
+
+    res = fdt_property_string(fdt, "compatible", "numa-distance-map-v1");
+    if ( res )
+        return res;
+
+    res = fdt_property(fdt, "distance-matrix", matrix, count * 3 * 
sizeof(uint32_t));
+    if ( res )
+        return res;
+
+    res = fdt_end_node(fdt);
+    if ( res )
+        return res;
+
+    return 0;
+}
+#else /* CONFIG_NUMA */
+#define make_distance_map_node(d, fdt) (0)
+#endif /* CONFIG_NUMA */
+
 int __init add_ext_regions(unsigned long s_gfn, unsigned long e_gfn,
                            void *data)
 {
@@ -1568,6 +1613,7 @@ static int __init handle_node(struct domain *d, struct 
kernel_info *kinfo,
         DT_MATCH_TYPE("memory"),
         /* The memory mapped timer is not supported by Xen. */
         DT_MATCH_COMPATIBLE("arm,armv7-timer-mem"),
+        DT_MATCH_COMPATIBLE("numa-distance-map-v1"),
         { /* sentinel */ },
     };
     static const struct dt_device_match timer_matches[] __initconst =
@@ -1733,6 +1779,10 @@ static int __init handle_node(struct domain *d, struct 
kernel_info *kinfo,
         if ( res )
             return res;
 
+        res = make_distance_map_node(d, kinfo->fdt);
+        if ( res )
+            return res;
+
         res = sci_dt_finalize(d, kinfo->fdt);
         if ( res )
             return res;
-- 
2.43.0