[Qemu-devel] [RFC PATCH v2 04/23] spapr: Support ibm, lrdr-capacity device tree property

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

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.

Define minimum hotpluggable memory size as 256MB and start storing maximum
possible memory for the guest in sPAPREnvironment.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
 docs/specs/ppc-spapr-hotplug.txt | 18 ++++++++++++++++++
 hw/ppc/spapr.c                   |  3 ++-
 hw/ppc/spapr_rtas.c              | 18 ++++++++++++++++--
 include/hw/ppc/spapr.h           |  7 +++++--
 4 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/docs/specs/ppc-spapr-hotplug.txt b/docs/specs/ppc-spapr-hotplug.txt
index d35771c..46e0719 100644
--- a/docs/specs/ppc-spapr-hotplug.txt
+++ b/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
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 3b26ede..36ff754 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -777,7 +777,7 @@ static void spapr_finalize_fdt(sPAPREnvironment *spapr,
     }
 
     /* RTAS */
-    ret = spapr_rtas_device_tree_setup(fdt, rtas_addr, rtas_size);
+    ret = spapr_rtas_device_tree_setup(spapr, fdt, rtas_addr, rtas_size);
     if (ret < 0) {
         fprintf(stderr, "Couldn't set up RTAS device tree properties\n");
     }
@@ -1536,6 +1536,7 @@ static void ppc_spapr_init(MachineState *machine)
 
     /* allocate RAM */
     spapr->ram_limit = ram_size;
+    spapr->maxram_limit = machine->maxram_size;
     memory_region_allocate_system_memory(ram, NULL, "ppc_spapr.ram",
                                          spapr->ram_limit);
     memory_region_add_subregion(sysmem, 0, ram);
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index b4047af..57ec97a 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/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"
@@ -613,11 +614,12 @@ void spapr_rtas_register(int token, const char *name, spapr_rtas_fn fn)
     rtas_table[token].fn = fn;
 }
 
-int spapr_rtas_device_tree_setup(void *fdt, hwaddr rtas_addr,
-                                 hwaddr rtas_size)
+int spapr_rtas_device_tree_setup(sPAPREnvironment *spapr, void *fdt,
+                                 hwaddr rtas_addr, hwaddr rtas_size)
 {
     int ret;
     int i;
+    uint32_t lrdr_capacity[5];
 
     ret = fdt_add_mem_rsv(fdt, rtas_addr, rtas_size);
     if (ret < 0) {
@@ -666,6 +668,18 @@ int spapr_rtas_device_tree_setup(void *fdt, hwaddr rtas_addr,
         }
 
     }
+
+    lrdr_capacity[0] = cpu_to_be32(spapr->maxram_limit >> 32);
+    lrdr_capacity[1] = cpu_to_be32(spapr->maxram_limit & 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 0;
 }
 
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 4578433..ecac6e3 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -20,6 +20,7 @@ typedef struct sPAPREnvironment {
     DeviceState *rtc;
 
     hwaddr ram_limit;
+    hwaddr maxram_limit;
     void *htab;
     uint32_t htab_shift;
     hwaddr rma_size;
@@ -497,8 +498,8 @@ void spapr_rtas_register(int token, const char *name, spapr_rtas_fn fn);
 target_ulong spapr_rtas_call(PowerPCCPU *cpu, sPAPREnvironment *spapr,
                              uint32_t token, uint32_t nargs, target_ulong args,
                              uint32_t nret, target_ulong rets);
-int spapr_rtas_device_tree_setup(void *fdt, hwaddr rtas_addr,
-                                 hwaddr rtas_size);
+int spapr_rtas_device_tree_setup(sPAPREnvironment *spapr, void *fdt,
+                                 hwaddr rtas_addr, hwaddr rtas_size);
 
 #define SPAPR_TCE_PAGE_SHIFT   12
 #define SPAPR_TCE_PAGE_SIZE    (1ULL << SPAPR_TCE_PAGE_SHIFT)
@@ -539,6 +540,8 @@ struct sPAPREventLogEntry {
     QTAILQ_ENTRY(sPAPREventLogEntry) next;
 };
 
+#define SPAPR_MEMORY_BLOCK_SIZE (1 << 28) /* 256MB */
+
 void spapr_events_init(sPAPREnvironment *spapr);
 void spapr_events_fdt_skel(void *fdt, uint32_t epow_irq);
 int spapr_h_cas_compose_response(target_ulong addr, target_ulong size);
-- 
2.1.0