spapr: Add ibm, chip-id property in device tree

This adds a "ibm,chip-id" property for CPU nodes which should be the same
for all cores in the same CPU socket. The recent guest kernels use this
information to associate threads with sockets.

Refer to the kernel commit 256f2d4b463d3030ebc8d2b54f427543814a2bdc
for more details.

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

hw/ppc/spapr.c

@@ -313,6 +313,9 @@ static void *spapr_create_fdt_skel(hwaddr initrd_base,
     uint32_t interrupt_server_ranges_prop[] = {0, cpu_to_be32(smp_cpus)};
     int i, smt = kvmppc_smt_threads();
     unsigned char vec5[] = {0x0, 0x0, 0x0, 0x0, 0x0, 0x80};
+    QemuOpts *opts = qemu_opts_find(qemu_find_opts("smp-opts"), NULL);
+    unsigned sockets = opts ? qemu_opt_get_number(opts, "sockets", 0) : 0;
+    uint32_t cpus_per_socket = sockets ? (smp_cpus / sockets) : 1;
 
     fdt = g_malloc0(FDT_MAX_SIZE);
     _FDT((fdt_create(fdt, FDT_MAX_SIZE)));
@@ -470,6 +473,9 @@ static void *spapr_create_fdt_skel(hwaddr initrd_base,
                                page_sizes_prop, page_sizes_prop_size)));
         }
 
+        _FDT((fdt_property_cell(fdt, "ibm,chip-id",
+                                cs->cpu_index / cpus_per_socket)));
+
         _FDT((fdt_end_node(fdt)));
     }