[Qemu-devel] [PATCH v6 1/6] spapr: Initialize hotplug memory address space

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

Initialize a hotplug memory region under which all the hotplugged
memory is accommodated. Also enable memory hotplug by setting
CONFIG_MEM_HOTPLUG.

Modelled on i386 memory hotplug.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
 default-configs/ppc64-softmmu.mak |  1 +
 hw/ppc/spapr.c                    | 18 ++++++++++++++++++
 include/hw/ppc/spapr.h            | 12 ++++++++++++
 3 files changed, 31 insertions(+)

diff --git a/default-configs/ppc64-softmmu.mak b/default-configs/ppc64-softmmu.mak
index ab62cc7..e77cb1a 100644
--- a/default-configs/ppc64-softmmu.mak
+++ b/default-configs/ppc64-softmmu.mak
@@ -52,3 +52,4 @@ CONFIG_XICS_KVM=$(and $(CONFIG_PSERIES),$(CONFIG_KVM))
 # For PReP
 CONFIG_MC146818RTC=y
 CONFIG_ISA_TESTDEV=y
+CONFIG_MEM_HOTPLUG=y
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 5ca817c..241ecad 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1549,6 +1549,24 @@ static void ppc_spapr_init(MachineState *machine)
         memory_region_add_subregion(sysmem, 0, rma_region);
     }
 
+    /* initialize hotplug memory address space */
+    if (machine->ram_size < machine->maxram_size) {
+        ram_addr_t hotplug_mem_size = machine->maxram_size - machine->ram_size;
+
+        if (machine->ram_slots > SPAPR_MAX_RAM_SLOTS) {
+            error_report("unsupported amount of memory slots: %"PRIu64,
+                          machine->ram_slots);
+            exit(EXIT_FAILURE);
+        }
+
+        spapr->hotplug_memory.base = ROUND_UP(machine->ram_size,
+                                              SPAPR_HOTPLUG_MEM_ALIGN);
+        memory_region_init(&spapr->hotplug_memory.mr, OBJECT(spapr),
+                           "hotplug-memory", hotplug_mem_size);
+        memory_region_add_subregion(sysmem, spapr->hotplug_memory.base,
+                                    &spapr->hotplug_memory.mr);
+    }
+
     filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, "spapr-rtas.bin");
     if (!filename) {
         error_report("Could not find LPAR rtas '%s'", "spapr-rtas.bin");
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 91a61ab..8a1929b 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -5,6 +5,7 @@
 #include "hw/boards.h"
 #include "hw/ppc/xics.h"
 #include "hw/ppc/spapr_drc.h"
+#include "hw/mem/pc-dimm.h"
 
 struct VIOsPAPRBus;
 struct sPAPRPHBState;
@@ -76,6 +77,7 @@ struct sPAPRMachineState {
 
     /*< public >*/
     char *kvm_type;
+    MemoryHotplugState hotplug_memory;
 };
 
 #define H_SUCCESS         0
@@ -609,4 +611,14 @@ int spapr_rtc_import_offset(DeviceState *dev, int64_t legacy_offset);
 
 #define SPAPR_MEMORY_BLOCK_SIZE (1 << 28) /* 256MB */
 
+/*
+ * This defines the maximum number of DIMM slots we can have for sPAPR
+ * guest. This is not defined by sPAPR but we are defining it to 32 slots
+ * based on default number of slots provided by PowerPC kernel.
+ */
+#define SPAPR_MAX_RAM_SLOTS     32
+
+/* 1GB alignment for hotplug memory region */
+#define SPAPR_HOTPLUG_MEM_ALIGN (1ULL << 30)
+
 #endif /* !defined (__HW_SPAPR_H__) */
-- 
2.1.0