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-rw-r--r--hw/arm/boot.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index 57efb61ee4..74ad397b1f 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -599,10 +599,23 @@ int arm_load_dtb(hwaddr addr, const struct arm_boot_info *binfo,
     }
     g_strfreev(node_path);
 
+    /*
+     * We drop all the memory nodes which correspond to empty NUMA nodes
+     * from the device tree, because the Linux NUMA binding document
+     * states they should not be generated. Linux will get the NUMA node
+     * IDs of the empty NUMA nodes from the distance map if they are needed.
+     * This means QEMU users may be obliged to provide command lines which
+     * configure distance maps when the empty NUMA node IDs are needed and
+     * Linux's default distance map isn't sufficient.
+     */
     if (ms->numa_state != NULL && ms->numa_state->num_nodes > 0) {
         mem_base = binfo->loader_start;
         for (i = 0; i < ms->numa_state->num_nodes; i++) {
             mem_len = ms->numa_state->nodes[i].node_mem;
+            if (!mem_len) {
+                continue;
+            }
+
             rc = fdt_add_memory_node(fdt, acells, mem_base,
                                      scells, mem_len, i);
             if (rc < 0) {