[Qemu-devel] [RFC PATCH v2 23/23] 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        | 119 +++++++++++++++++++++++++++++++++++++++++++++++++-
 hw/ppc/spapr_events.c |   3 ++
 2 files changed, 120 insertions(+), 2 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 4e844ab..bc46acd 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -61,7 +61,8 @@
 #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:
@@ -902,6 +903,10 @@ int spapr_h_cas_compose_response(target_ulong addr, target_ulong size,
         _FDT((spapr_populate_memory(spapr, fdt)));
     }
 
+    if (spapr->dr_lmb_enabled) {
+        _FDT(spapr_drc_populate_dt(fdt, 0, NULL, SPAPR_DR_CONNECTOR_TYPE_LMB));
+    }
+
     /* Pack resulting tree */
     _FDT((fdt_pack(fdt)));
 
@@ -2185,6 +2190,109 @@ static void spapr_cpu_socket_unplug(HotplugHandler *hotplug_dev,
     object_child_foreach(OBJECT(dev), spapr_cpu_core_unplug, errp);
 }
 
+static void spapr_add_lmbs(uint64_t addr, uint64_t size, Error **errp)
+{
+    sPAPRDRConnector *drc;
+    uint32_t nr_lmbs = size/SPAPR_MEMORY_BLOCK_SIZE;
+    int i;
+
+    if (size % SPAPR_MEMORY_BLOCK_SIZE) {
+        error_setg(errp, "Hotplugged memory size must be a multiple of "
+                      "%d MB", SPAPR_MEMORY_BLOCK_SIZE/(1024 * 1024));
+        return;
+    }
+
+    for (i = 0; i < nr_lmbs; i++) {
+        drc = spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_LMB,
+                addr/SPAPR_MEMORY_BLOCK_SIZE);
+        g_assert(drc);
+        spapr_hotplug_req_add_event(drc);
+        addr += SPAPR_MEMORY_BLOCK_SIZE;
+    }
+}
+
+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 existing_dimms_capacity = 0;
+    uint64_t align = TARGET_PAGE_SIZE;
+    uint64_t addr;
+
+    addr = object_property_get_int(OBJECT(dimm), PC_DIMM_ADDR_PROP, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    if (memory_region_get_alignment(mr) && ms->enforce_aligned_dimm) {
+        align = memory_region_get_alignment(mr);
+    }
+
+    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;
+    }
+
+    existing_dimms_capacity = pc_existing_dimms_capacity(&local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    if (existing_dimms_capacity + memory_region_size(mr) >
+        machine->maxram_size - machine->ram_size) {
+        error_setg(&local_err, "not enough space, currently 0x%" PRIx64
+                   " in use of total hot pluggable 0x" RAM_ADDR_FMT,
+                   existing_dimms_capacity,
+                   machine->maxram_size - machine->ram_size);
+        goto out;
+    }
+
+    object_property_set_int(OBJECT(dev), addr, PC_DIMM_ADDR_PROP, &local_err);
+    if (local_err) {
+        goto out;
+    }
+    trace_mhp_pc_dimm_assigned_address(addr);
+
+    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;
+    }
+    trace_mhp_pc_dimm_assigned_slot(slot);
+
+    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);
+
+    spapr_add_lmbs(addr, memory_region_size(mr), &local_err);
+
+out:
+    error_propagate(errp, local_err);
+}
+
 static void spapr_machine_device_plug(HotplugHandler *hotplug_dev,
                                       DeviceState *dev, Error **errp)
 {
@@ -2197,6 +2305,9 @@ static void spapr_machine_device_plug(HotplugHandler *hotplug_dev,
         if (dev->hotplugged && spapr->dr_cpu_enabled) {
             spapr_cpu_plug(hotplug_dev, dev, errp);
         }
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) &&
+                spapr->dr_lmb_enabled) {
+        spapr_memory_plug(hotplug_dev, dev, errp);
     }
 }
 
@@ -2207,6 +2318,9 @@ static void spapr_machine_device_unplug(HotplugHandler *hotplug_dev,
         if (dev->hotplugged && spapr->dr_cpu_enabled) {
             spapr_cpu_socket_unplug(hotplug_dev, dev, errp);
         }
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) &&
+                spapr->dr_lmb_enabled) {
+        error_setg(errp, "Memory hot unplug not supported by sPAPR");
     }
 }
 
@@ -2214,7 +2328,8 @@ static HotplugHandler *spapr_get_hotpug_handler(MachineState *machine,
                                              DeviceState *dev)
 {
     if (object_dynamic_cast(OBJECT(dev), TYPE_CPU) ||
-        object_dynamic_cast(OBJECT(dev), TYPE_CPU_SOCKET)) {
+        object_dynamic_cast(OBJECT(dev), TYPE_CPU_SOCKET) ||
+        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 4ae818a..e2a22d2 100644
--- a/hw/ppc/spapr_events.c
+++ b/hw/ppc/spapr_events.c
@@ -431,6 +431,9 @@ 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:
         /* we shouldn't be signaling hotplug events for resources
          * that don't support them
-- 
2.1.0