[PATCH v3 02/22] xen/common: Default function to get the distance between nodes

[Hirokazu Takahashi <taka@xxxxxxxxxxxxx>]

Provide a fallback function to get the distance between NUMA nodes.

Signed-off-by: Hirokazu Takahashi <taka@xxxxxxxxxxxxx>
---
 xen/common/Makefile            |  1 +
 xen/common/numa-distance-map.c | 19 +++++++++++++++++++
 xen/include/xen/numa.h         |  2 ++
 3 files changed, 22 insertions(+)
 create mode 100644 xen/common/numa-distance-map.c

diff --git a/xen/common/Makefile b/xen/common/Makefile
index 6018e25614..062f9ab72b 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -32,6 +32,7 @@ obj-$(CONFIG_VM_EVENT) += monitor.o
 obj-y += multicall.o
 obj-y += notifier.o
 obj-$(CONFIG_NUMA) += numa.o
+obj-$(CONFIG_NUMA_DISTANCE_MAP) += numa-distance-map.o
 obj-y += page_alloc.o
 obj-y += pdx.o
 obj-y += percpu.o
diff --git a/xen/common/numa-distance-map.c b/xen/common/numa-distance-map.c
new file mode 100644
index 0000000000..73344f7f33
--- /dev/null
+++ b/xen/common/numa-distance-map.c
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <xen/errno.h>
+#include <xen/init.h>
+#include <xen/nodemask.h>
+#include <xen/numa.h>
+
+#define LOCAL_DISTANCE      10
+#define REMOTE_DISTANCE     20
+
+/*
+ * Get the distance between node 'from' and node 'to'.
+ */
+uint8_t numa_node_distance(unsigned int from, unsigned int to)
+{
+    if ( from != to )
+        return REMOTE_DISTANCE;
+    return LOCAL_DISTANCE;
+}
diff --git a/xen/include/xen/numa.h b/xen/include/xen/numa.h
index f6c1f27ca1..18c22d3d30 100644
--- a/xen/include/xen/numa.h
+++ b/xen/include/xen/numa.h
@@ -128,6 +128,8 @@ extern bool numa_update_node_memblks(nodeid_t node, 
unsigned int arch_nid,
                                      paddr_t start, paddr_t size, bool 
hotplug);
 extern void numa_set_processor_nodes_parsed(nodeid_t node);
 
+extern uint8_t numa_node_distance(unsigned int from, unsigned int to);
+
 #else
 
 /* Fake one node for now. See also node_online_map. */
-- 
2.43.0