[PATCH 1/2] numa: Set default distance map if needed

[Gavin Shan]

The following option is used to specify the distance map. It's
possible the option isn't provided by user. In this case, the
distance map isn't populated and exposed to platform. On the
other hand, the empty NUMA node, where no memory resides, is
allowed on ARM64 virt platform. For these empty NUMA nodes,
their corresponding device-tree nodes aren't populated, but
their NUMA IDs should be included in the "/distance-map"
device-tree node, so that kernel can probe them properly if
device-tree is used.

  -numa,dist,src=<numa_id>,dst=<numa_id>,val=<distance>

So when user doesn't specify distance map, we need to generate
the default distance map, where the local and remote distances
are 10 and 20 separately. This adds an extra parameter to the
exiting complete_init_numa_distance() to generate the default
distance map for this case.

Signed-off-by: Gavin Shan <gshan@redhat.com>
---
 hw/core/numa.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/hw/core/numa.c b/hw/core/numa.c
index 510d096a88..fdb3a4aeca 100644
--- a/hw/core/numa.c
+++ b/hw/core/numa.c
@@ -594,7 +594,7 @@ static void validate_numa_distance(MachineState *ms)
     }
 }
 
-static void complete_init_numa_distance(MachineState *ms)
+static void complete_init_numa_distance(MachineState *ms, bool is_default)
 {
     int src, dst;
     NodeInfo *numa_info = ms->numa_state->nodes;
@@ -609,6 +609,8 @@ static void complete_init_numa_distance(MachineState *ms)
             if (numa_info[src].distance[dst] == 0) {
                 if (src == dst) {
                     numa_info[src].distance[dst] = NUMA_DISTANCE_MIN;
+                } else if (is_default) {
+                    numa_info[src].distance[dst] = NUMA_DISTANCE_DEFAULT;
                 } else {
                     numa_info[src].distance[dst] = 
numa_info[dst].distance[src];
                 }
@@ -716,13 +718,20 @@ void numa_complete_configuration(MachineState *ms)
          * A->B != distance B->A, then that means the distance table is
          * asymmetric. In this case, the distances for both directions
          * of all node pairs are required.
+         *
+         * The default node pair distances, which are 10 and 20 for the
+         * local and remote nodes separatly, are provided if user doesn't
+         * specify any node pair distances.
          */
         if (ms->numa_state->have_numa_distance) {
             /* Validate enough NUMA distance information was provided. */
             validate_numa_distance(ms);
 
             /* Validation succeeded, now fill in any missing distances. */
-            complete_init_numa_distance(ms);
+            complete_init_numa_distance(ms, false);
+        } else {
+            complete_init_numa_distance(ms, true);
+            ms->numa_state->have_numa_distance = true;
         }
     }
 }
-- 
2.23.0