[Qemu-devel] [RFC PATCH v4 5/5] spapr: Memory hotplug support

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

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

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
 hw/ppc/spapr.c        | 126 ++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/ppc/spapr_events.c |   8 ++--
 2 files changed, 131 insertions(+), 3 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 24e5a8c..173f639 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -33,6 +33,7 @@
 #include "sysemu/block-backend.h"
 #include "sysemu/cpus.h"
 #include "sysemu/kvm.h"
+#include "sysemu/device_tree.h"
 #include "kvm_ppc.h"
 #include "mmu-hash64.h"
 #include "qom/cpu.h"
@@ -930,6 +931,10 @@ static void spapr_finalize_fdt(sPAPRMachineState *spapr,
         spapr_populate_chosen_stdout(fdt, spapr->vio_bus);
     }
 
+    if (spapr->dr_lmb_enabled) {
+        _FDT(spapr_drc_populate_dt(fdt, 0, NULL, SPAPR_DR_CONNECTOR_TYPE_LMB));
+    }
+
     _FDT((fdt_pack(fdt)));
 
     if (fdt_totalsize(fdt) > FDT_MAX_SIZE) {
@@ -2037,12 +2042,129 @@ static void spapr_nmi(NMIState *n, int cpu_index, Error **errp)
     }
 }
 
+static void spapr_add_lmbs(DeviceState *dev, uint64_t addr, uint64_t size,
+                           uint32_t node, Error **errp)
+{
+    sPAPRDRConnector *drc;
+    sPAPRDRConnectorClass *drck;
+    uint32_t nr_lmbs = size/SPAPR_MEMORY_BLOCK_SIZE;
+    int i, fdt_offset, fdt_size;
+    void *fdt;
+    Error *local_err = NULL;
+
+    if (size % SPAPR_MEMORY_BLOCK_SIZE) {
+        error_setg(errp, "Hotplugged memory size must be a multiple of "
+                      "%lld MB", SPAPR_MEMORY_BLOCK_SIZE/M_BYTE);
+        return;
+    }
+
+    /*
+     * Check for DRC connectors and send hotplug notification to the
+     * guest only in case of hotplugged memory. This allows cold plugged
+     * memory to be specified at boot time.
+     */
+    if (!dev->hotplugged) {
+        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);
+
+        fdt = create_device_tree(&fdt_size);
+        fdt_offset = spapr_populate_memory_node(fdt, node, addr,
+                                                SPAPR_MEMORY_BLOCK_SIZE);
+
+        drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
+        drck->attach(drc, dev, fdt, fdt_offset, !dev->hotplugged, &local_err);
+        if (local_err) {
+            g_free(fdt);
+            error_propagate(errp, local_err);
+            return;
+        }
+
+        spapr_hotplug_req_add_event(drc);
+        addr += SPAPR_MEMORY_BLOCK_SIZE;
+    }
+}
+
+static void spapr_memory_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
+                              uint32_t node, Error **errp)
+{
+    Error *local_err = NULL;
+    sPAPRMachineState *ms = SPAPR_MACHINE(hotplug_dev);
+    PCDIMMDevice *dimm = PC_DIMM(dev);
+    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
+    MemoryRegion *mr = ddc->get_memory_region(dimm);
+    uint64_t align = memory_region_get_alignment(mr);
+    uint64_t addr;
+
+    pc_dimm_memory_plug(dev, &ms->hotplug_memory, mr, align, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    addr = object_property_get_int(OBJECT(dimm), PC_DIMM_ADDR_PROP, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    spapr_add_lmbs(dev, addr, memory_region_size(mr), node, &local_err);
+    if (local_err) {
+        goto out;
+    }
+    return;
+
+out:
+    pc_dimm_memory_unplug(dev, &ms->hotplug_memory, mr);
+    error_propagate(errp, local_err);
+}
+
+static void spapr_machine_device_plug(HotplugHandler *hotplug_dev,
+                                      DeviceState *dev, Error **errp)
+{
+    sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
+
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+        uint32_t node;
+
+        if (!spapr->dr_lmb_enabled) {
+            error_setg(errp, "Memory hotplug not supported for this machine");
+            return;
+        }
+        node = object_property_get_int(OBJECT(dev), PC_DIMM_NODE_PROP, errp);
+        if (*errp) {
+            return;
+        }
+        spapr_memory_plug(hotplug_dev, dev, node, errp);
+    }
+}
+
+static void spapr_machine_device_unplug(HotplugHandler *hotplug_dev,
+                                      DeviceState *dev, Error **errp)
+{
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+        error_setg(errp, "Memory hot unplug not supported by sPAPR");
+    }
+}
+
+static HotplugHandler *spapr_get_hotpug_handler(MachineState *machine,
+                                             DeviceState *dev)
+{
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+        return HOTPLUG_HANDLER(machine);
+    }
+    return NULL;
+}
+
 static void spapr_machine_class_init(ObjectClass *oc, void *data)
 {
     MachineClass *mc = MACHINE_CLASS(oc);
     sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(oc);
     FWPathProviderClass *fwc = FW_PATH_PROVIDER_CLASS(oc);
     NMIClass *nc = NMI_CLASS(oc);
+    HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(oc);
 
     mc->init = ppc_spapr_init;
     mc->reset = ppc_spapr_reset;
@@ -2053,6 +2175,9 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
     mc->default_ram_size = 512 * M_BYTE;
     mc->kvm_type = spapr_kvm_type;
     mc->has_dynamic_sysbus = true;
+    mc->get_hotplug_handler = spapr_get_hotpug_handler;
+    hc->plug = spapr_machine_device_plug;
+    hc->unplug = spapr_machine_device_unplug;
 
     smc->dr_lmb_enabled = false;
     fwc->get_dev_path = spapr_get_fw_dev_path;
@@ -2070,6 +2195,7 @@ static const TypeInfo spapr_machine_info = {
     .interfaces = (InterfaceInfo[]) {
         { TYPE_FW_PATH_PROVIDER },
         { TYPE_NMI },
+        { TYPE_HOTPLUG_HANDLER },
         { }
     },
 };
diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
index f626eb7..98bf7ae 100644
--- a/hw/ppc/spapr_events.c
+++ b/hw/ppc/spapr_events.c
@@ -427,14 +427,16 @@ static void spapr_hotplug_req_event(sPAPRDRConnector *drc, uint8_t hp_action)
     hp->hdr.section_length = cpu_to_be16(sizeof(*hp));
     hp->hdr.section_version = 1; /* includes extended modifier */
     hp->hotplug_action = hp_action;
-
+    hp->drc.index = cpu_to_be32(drck->get_index(drc));
+    hp->hotplug_identifier = RTAS_LOG_V6_HP_ID_DRC_INDEX;
 
     switch (drc_type) {
     case SPAPR_DR_CONNECTOR_TYPE_PCI:
-        hp->drc.index = cpu_to_be32(drck->get_index(drc));
-        hp->hotplug_identifier = RTAS_LOG_V6_HP_ID_DRC_INDEX;
         hp->hotplug_type = RTAS_LOG_V6_HP_TYPE_PCI;
         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