[Qemu-devel] [RFC PATCH v1 13/13] spapr: Memory hotplug support

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

Make use of pc-dimm infrastructure to support memory hotplug
for PowerPC.

Modelled on i386 memory hotplug.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
 hw/ppc/spapr.c        | 107 +++++++++++++++++++++++++++++++++++++++++++++++++-
 hw/ppc/spapr_events.c |   3 ++
 2 files changed, 108 insertions(+), 2 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 6964b06..1ffff39 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -58,7 +58,8 @@
 #include "hw/nmi.h"
 
 #include "hw/compat.h"
-
+#include "hw/mem/pc-dimm.h"
+#include "qapi/qmp/qerror.h"
 #include <libfdt.h>
 
 /* SLOF memory layout:
@@ -2165,6 +2166,103 @@ static void spapr_cpu_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,
     return;
 }
 
+static int spapr_dimms_capacity(Object *obj, void *opaque)
+{
+    Error *local_err = NULL;
+    uint64_t *size = opaque;
+
+    if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
+        (*size) += object_property_get_int(obj, PC_DIMM_SIZE_PROP, &local_err);
+
+        if (local_err) {
+            qerror_report_err(local_err);
+            error_free(local_err);
+            return 1;
+        }
+    }
+
+    object_child_foreach(obj, spapr_dimms_capacity, opaque);
+    return 0;
+}
+
+static void spapr_memory_plug(HotplugHandler *hotplug_dev,
+                         DeviceState *dev, Error **errp)
+{
+    int slot;
+    Error *local_err = NULL;
+    sPAPRMachineState *ms = SPAPR_MACHINE(hotplug_dev);
+    MachineState *machine = MACHINE(hotplug_dev);
+    PCDIMMDevice *dimm = PC_DIMM(dev);
+    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
+    MemoryRegion *mr = ddc->get_memory_region(dimm);
+    uint64_t dimms_capacity = 0;
+    uint64_t align = TARGET_PAGE_SIZE; /* TODO: enforce alignment */
+    uint64_t addr;
+    sPAPRDRConnector *drc;
+
+    addr = object_property_get_int(OBJECT(dimm), PC_DIMM_ADDR_PROP, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    addr = pc_dimm_get_free_addr(ms->hotplug_memory_base,
+                                 memory_region_size(&ms->hotplug_memory),
+                                 !addr ? NULL : &addr, align,
+                                 memory_region_size(mr), &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    if (spapr_dimms_capacity(OBJECT(machine), &dimms_capacity)) {
+        error_setg(&local_err, "failed to get total size of existing DIMMs");
+        goto out;
+    }
+
+    if (dimms_capacity > machine->maxram_size - machine->ram_size) {
+        error_setg(&local_err, "not enough space, proposed use of 0x%" PRIx64
+                   " from total of 0x" RAM_ADDR_FMT,
+                   dimms_capacity, machine->maxram_size);
+        goto out;
+    }
+
+    object_property_set_int(OBJECT(dev), addr, PC_DIMM_ADDR_PROP, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    slot = object_property_get_int(OBJECT(dev), PC_DIMM_SLOT_PROP, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    slot = pc_dimm_get_free_slot(slot == PC_DIMM_UNASSIGNED_SLOT ? NULL : &slot,
+                                 machine->ram_slots, &local_err);
+    if (local_err) {
+        goto out;
+    }
+    object_property_set_int(OBJECT(dev), slot, PC_DIMM_SLOT_PROP, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    if (kvm_enabled() && !kvm_has_free_slot(machine)) {
+        error_setg(&local_err, "hypervisor has no free memory slots left");
+        goto out;
+    }
+
+    memory_region_add_subregion(&ms->hotplug_memory,
+                                addr - ms->hotplug_memory_base, mr);
+    vmstate_register_ram(mr, dev);
+
+    drc = spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_LMB,
+            addr/SPAPR_MIN_MEMORY_BLOCK_SIZE);
+    g_assert(drc);
+    spapr_hotplug_req_add_event(drc);
+
+out:
+    error_propagate(errp, local_err);
+}
+
 static void spapr_machine_device_plug(HotplugHandler *hotplug_dev,
                                       DeviceState *dev, Error **errp)
 {
@@ -2172,6 +2270,8 @@ static void spapr_machine_device_plug(HotplugHandler *hotplug_dev,
         if (dev->hotplugged) {
             spapr_cpu_plug(hotplug_dev, dev, errp);
         }
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+        spapr_memory_plug(hotplug_dev, dev, errp);
     }
 }
 
@@ -2182,13 +2282,16 @@ static void spapr_machine_device_unplug(HotplugHandler *hotplug_dev,
         if (dev->hotplugged) {
             spapr_cpu_unplug(hotplug_dev, dev, errp);
         }
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+        error_setg(errp, "Memory hot unplug is not yet supported\n");
     }
 }
 
 static HotplugHandler *spapr_get_hotpug_handler(MachineState *machine,
                                              DeviceState *dev)
 {
-    if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
+    if (object_dynamic_cast(OBJECT(dev), TYPE_CPU) ||
+            object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
         return HOTPLUG_HANDLER(machine);
     }
     return NULL;
diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
index 035d8c9..f559661 100644
--- a/hw/ppc/spapr_events.c
+++ b/hw/ppc/spapr_events.c
@@ -374,6 +374,9 @@ static void spapr_hotplug_req_event(sPAPRDRConnector *drc, uint8_t hp_action)
     case SPAPR_DR_CONNECTOR_TYPE_CPU:
         hp->hotplug_type = RTAS_LOG_V6_HP_TYPE_CPU;
         break;
+    case SPAPR_DR_CONNECTOR_TYPE_LMB:
+        hp->hotplug_type = RTAS_LOG_V6_HP_TYPE_MEMORY;
+        break;
     default:
         /* skip notification for unknown connector types */
         g_free(new_hp);
-- 
2.1.0