spapr: Support ibm, lrdr-capacity device tree property

Add support for ibm,lrdr-capacity since this is needed by the guest
kernel to know about the possible hot-pluggable CPUs and Memory. With
this, pseries kernels will start reporting correct maxcpus in
/sys/devices/system/cpu/possible.

Also define the minimum hotpluggable memory size as 256MB.
Signed-off-by: NBharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
[agraf: Fix compile error on 32bit hosts]
Signed-off-by: NAlexander Graf <agraf@suse.de>

docs/specs/ppc-spapr-hotplug.txt

@@ -284,4 +284,22 @@ struct rtas_event_log_v6_hp {
     } drc;
 } QEMU_PACKED;
 
+== ibm,lrdr-capacity ==
+
+ibm,lrdr-capacity is a property in the /rtas device tree node that identifies
+the dynamic reconfiguration capabilities of the guest. It consists of a triple
+consisting of <phys>, <size> and <maxcpus>.
+
+  <phys>, encoded in BE format represents the maximum address in bytes and
+  hence the maximum memory that can be allocated to the guest.
+
+  <size>, encoded in BE format represents the size increments in which
+  memory can be hot-plugged to the guest.
+
+  <maxcpus>, a BE-encoded integer, represents the maximum number of
+  processors that the guest can have.
+
+pseries guests use this property to note the maximum allowed CPUs for the
+guest.
+
 [1] http://thread.gmane.org/gmane.linux.ports.ppc.embedded/75350/focus=106867

hw/ppc/spapr_rtas.c

@@ -29,6 +29,7 @@
 #include "sysemu/char.h"
 #include "hw/qdev.h"
 #include "sysemu/device_tree.h"
+#include "sysemu/cpus.h"
 
 #include "hw/ppc/spapr.h"
 #include "hw/ppc/spapr_vio.h"
@@ -651,6 +652,8 @@ int spapr_rtas_device_tree_setup(void *fdt, hwaddr rtas_addr,
 {
     int ret;
     int i;
+    uint32_t lrdr_capacity[5];
+    MachineState *machine = MACHINE(qdev_get_machine());
 
     ret = fdt_add_mem_rsv(fdt, rtas_addr, rtas_size);
     if (ret < 0) {
@@ -699,6 +702,19 @@ int spapr_rtas_device_tree_setup(void *fdt, hwaddr rtas_addr,
         }
 
     }
+
+    lrdr_capacity[0] = cpu_to_be32(((uint64_t)machine->maxram_size) >> 32);
+    lrdr_capacity[1] = cpu_to_be32(machine->maxram_size & 0xffffffff);
+    lrdr_capacity[2] = 0;
+    lrdr_capacity[3] = cpu_to_be32(SPAPR_MEMORY_BLOCK_SIZE);
+    lrdr_capacity[4] = cpu_to_be32(max_cpus/smp_threads);
+    ret = qemu_fdt_setprop(fdt, "/rtas", "ibm,lrdr-capacity", lrdr_capacity,
+                     sizeof(lrdr_capacity));
+    if (ret < 0) {
+        fprintf(stderr, "Couldn't add ibm,lrdr-capacity rtas property\n");
+        return ret;
+    }
+
     return 0;
 }
 

include/hw/ppc/spapr.h

@@ -607,4 +607,6 @@ void spapr_ccs_reset_hook(void *opaque);
 void spapr_rtc_read(DeviceState *dev, struct tm *tm, uint32_t *ns);
 int spapr_rtc_import_offset(DeviceState *dev, int64_t legacy_offset);
 
+#define SPAPR_MEMORY_BLOCK_SIZE (1 << 28) /* 256MB */
+
 #endif /* !defined (__HW_SPAPR_H__) */