spapr: Add ibm,max-associativity-domains property

Now recent kernels (i.e. since linux-stable commit a346137e9142
("powerpc/numa: Use ibm,max-associativity-domains to discover possible nodes")
support this property to mark initially memory-less NUMA nodes as "possible"
to allow further memory hot-add to them.

Advertise this property for pSeries machines to let guest kernels detect
maximum supported node configuration and benefit from kernel side change
when hot-add memory to specific, possibly empty before, NUMA node.

Signed-off-by: Serhii Popovych <spopovyc@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

hw/ppc/spapr.c

@@ -909,6 +909,13 @@ static void spapr_dt_rtas(sPAPRMachineState *spapr, void *fdt)
         0, cpu_to_be32(SPAPR_MEMORY_BLOCK_SIZE),
         cpu_to_be32(max_cpus / smp_threads),
     };
+    uint32_t maxdomains[] = {
+        cpu_to_be32(4),
+        cpu_to_be32(0),
+        cpu_to_be32(0),
+        cpu_to_be32(0),
+        cpu_to_be32(nb_numa_nodes ? nb_numa_nodes - 1 : 0),
+    };
 
     _FDT(rtas = fdt_add_subnode(fdt, 0, "rtas"));
 
@@ -945,6 +952,9 @@ static void spapr_dt_rtas(sPAPRMachineState *spapr, void *fdt)
     _FDT(fdt_setprop(fdt, rtas, "ibm,associativity-reference-points",
                      refpoints, sizeof(refpoints)));
 
+    _FDT(fdt_setprop(fdt, rtas, "ibm,max-associativity-domains",
+                     maxdomains, sizeof(maxdomains)));
+
     _FDT(fdt_setprop_cell(fdt, rtas, "rtas-error-log-max",
                           RTAS_ERROR_LOG_MAX));
     _FDT(fdt_setprop_cell(fdt, rtas, "rtas-event-scan-rate",