spapr: Refactor spapr_populate_memory() to allow memoryless nodes

Current QEMU does not support memoryless NUMA nodes, however
actual hardware may have them so it makes sense to have a way
to emulate them in QEMU. This prepares SPAPR for that.

This moves 2 calls of spapr_populate_memory_node() into
the existing loop over numa nodes so first several nodes may
have no memory and this still will work.

If there is no numa configuration, the code assumes there is just
a single node at 0 and it has all the guest memory.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>

hw/ppc/spapr.c

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 9b9b6c4..718a201 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -661,36 +661,36 @@
 
 static int spapr_populate_memory(sPAPREnvironment *spapr, void *fdt)
 {
-    hwaddr node0_size, mem_start, node_size;
-    int i;
+    hwaddr mem_start, node_size;
+    int i, nb_nodes = nb_numa_nodes;
+    NodeInfo *nodes = numa_info;
+    NodeInfo ramnode;
 
-    /* memory node(s) */
-    if (nb_numa_nodes > 1 && numa_info[0].node_mem < ram_size) {
-        node0_size = numa_info[0].node_mem;
-    } else {
-        node0_size = ram_size;
+    /* No NUMA nodes, assume there is just one node with whole RAM */
+    if (!nb_numa_nodes) {
+        nb_nodes = 1;
+        ramnode.node_mem = ram_size;
+        nodes = &ramnode;
     }
 
-    /* RMA */
-    spapr_populate_memory_node(fdt, 0, 0, spapr->rma_size);
-
-    /* RAM: Node 0 */
-    if (node0_size > spapr->rma_size) {
-        spapr_populate_memory_node(fdt, 0, spapr->rma_size,
-                                   node0_size - spapr->rma_size);
-    }
-
-    /* RAM: Node 1 and beyond */
-    mem_start = node0_size;
-    for (i = 1; i < nb_numa_nodes; i++) {
+    for (i = 0, mem_start = 0; i < nb_nodes; ++i) {
+        if (!nodes[i].node_mem) {
+            continue;
+        }
         if (mem_start >= ram_size) {
             node_size = 0;
         } else {
-            node_size = numa_info[i].node_mem;
+            node_size = nodes[i].node_mem;
             if (node_size > ram_size - mem_start) {
                 node_size = ram_size - mem_start;
             }
         }
+        if (!mem_start) {
+            /* ppc_spapr_init() checks for rma_size <= node0_size already */
+            spapr_populate_memory_node(fdt, i, 0, spapr->rma_size);
+            mem_start += spapr->rma_size;
+            node_size -= spapr->rma_size;
+        }
         spapr_populate_memory_node(fdt, i, mem_start, node_size);
         mem_start += node_size;
     }