[Qemu-devel] [RFC PATCH v1 06/13] spapr: CPU hotplug support

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

Support CPU hotplug via device-add command. Use the exising EPOW event
infrastructure to send CPU hotplug notification to the guest.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
 hw/ppc/spapr.c              | 205 +++++++++++++++++++++++++++++++++++++++++++-
 hw/ppc/spapr_events.c       |   8 +-
 target-ppc/translate_init.c |   6 ++
 3 files changed, 215 insertions(+), 4 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 515d770..a293a59 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -330,6 +330,8 @@ static void add_str(GString *s, const gchar *s1)
     g_string_append_len(s, s1, strlen(s1) + 1);
 }
 
+uint32_t cpus_per_socket;
+
 static void *spapr_create_fdt_skel(hwaddr initrd_base,
                                    hwaddr initrd_size,
                                    hwaddr kernel_size,
@@ -350,9 +352,9 @@ static void *spapr_create_fdt_skel(hwaddr initrd_base,
     unsigned char vec5[] = {0x0, 0x0, 0x0, 0x0, 0x0, 0x80};
     QemuOpts *opts = qemu_opts_find(qemu_find_opts("smp-opts"), NULL);
     unsigned sockets = opts ? qemu_opt_get_number(opts, "sockets", 0) : 0;
-    uint32_t cpus_per_socket = sockets ? (smp_cpus / sockets) : 1;
     char *buf;
 
+    cpus_per_socket = sockets ? (smp_cpus / sockets) : 1;
     add_str(hypertas, "hcall-pft");
     add_str(hypertas, "hcall-term");
     add_str(hypertas, "hcall-dabr");
@@ -1744,12 +1746,209 @@ static void spapr_nmi(NMIState *n, int cpu_index, Error **errp)
     }
 }
 
+/* TODO: Duplicates code from spapr_create_fdt_skel(), Fix this */
+static void spapr_populate_cpu_dt(CPUState *cs, void *fdt, int offset,
+            int drc_index)
+{
+    PowerPCCPU *cpu = POWERPC_CPU(cs);
+    CPUPPCState *env = &cpu->env;
+    PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cs);
+    int index = ppc_get_vcpu_dt_id(cpu);
+    uint32_t segs[] = {cpu_to_be32(28), cpu_to_be32(40),
+                       0xffffffff, 0xffffffff};
+    uint32_t tbfreq = kvm_enabled() ? kvmppc_get_tbfreq() : TIMEBASE_FREQ;
+    uint32_t cpufreq = kvm_enabled() ? kvmppc_get_clockfreq() : 1000000000;
+    uint32_t page_sizes_prop[64];
+    size_t page_sizes_prop_size;
+    int smpt = ppc_get_compat_smt_threads(cpu);
+    uint32_t servers_prop[smpt];
+    uint32_t gservers_prop[smpt * 2];
+    int i;
+    uint32_t pft_size_prop[] = {0, cpu_to_be32(spapr->htab_shift)};
+    uint32_t associativity[] = {cpu_to_be32(0x5),
+                                cpu_to_be32(0x0),
+                                cpu_to_be32(0x0),
+                                cpu_to_be32(0x0),
+                                cpu_to_be32(cs->numa_node),
+                                cpu_to_be32(index)};
+
+    _FDT((fdt_setprop_cell(fdt, offset, "reg", index)));
+    _FDT((fdt_setprop_string(fdt, offset, "device_type", "cpu")));
+
+    _FDT((fdt_setprop_cell(fdt, offset, "cpu-version", env->spr[SPR_PVR])));
+    _FDT((fdt_setprop_cell(fdt, offset, "d-cache-block-size",
+                        env->dcache_line_size)));
+    _FDT((fdt_setprop_cell(fdt, offset, "d-cache-line-size",
+                        env->dcache_line_size)));
+    _FDT((fdt_setprop_cell(fdt, offset, "i-cache-block-size",
+                        env->icache_line_size)));
+    _FDT((fdt_setprop_cell(fdt, offset, "i-cache-line-size",
+                            env->icache_line_size)));
+
+    if (pcc->l1_dcache_size) {
+        _FDT((fdt_setprop_cell(fdt, offset, "d-cache-size",
+            pcc->l1_dcache_size)));
+    } else {
+        fprintf(stderr, "Warning: Unknown L1 dcache size for cpu\n");
+    }
+    if (pcc->l1_icache_size) {
+        _FDT((fdt_setprop_cell(fdt, offset, "i-cache-size",
+            pcc->l1_icache_size)));
+    } else {
+        fprintf(stderr, "Warning: Unknown L1 icache size for cpu\n");
+    }
+
+    _FDT((fdt_setprop_cell(fdt, offset, "timebase-frequency", tbfreq)));
+    _FDT((fdt_setprop_cell(fdt, offset, "clock-frequency", cpufreq)));
+    _FDT((fdt_setprop_cell(fdt, offset, "ibm,slb-size", env->slb_nr)));
+    _FDT((fdt_setprop_string(fdt, offset, "status", "okay")));
+    _FDT((fdt_setprop(fdt, offset, "64-bit", NULL, 0)));
+
+    if (env->spr_cb[SPR_PURR].oea_read) {
+        _FDT((fdt_setprop(fdt, offset, "ibm,purr", NULL, 0)));
+    }
+
+    if (env->mmu_model & POWERPC_MMU_1TSEG) {
+        _FDT((fdt_setprop(fdt, offset, "ibm,processor-segment-sizes",
+                           segs, sizeof(segs))));
+    }
+
+    /* Advertise VMX/VSX (vector extensions) if available
+     *   0 / no property == no vector extensions
+     *   1               == VMX / Altivec available
+     *   2               == VSX available */
+    if (env->insns_flags & PPC_ALTIVEC) {
+        uint32_t vmx = (env->insns_flags2 & PPC2_VSX) ? 2 : 1;
+
+        _FDT((fdt_setprop_cell(fdt, offset, "ibm,vmx", vmx)));
+    }
+
+    /* Advertise DFP (Decimal Floating Point) if available
+     *   0 / no property == no DFP
+     *   1               == DFP available */
+    if (env->insns_flags2 & PPC2_DFP) {
+        _FDT((fdt_setprop_cell(fdt, offset, "ibm,dfp", 1)));
+    }
+
+    page_sizes_prop_size = create_page_sizes_prop(env, page_sizes_prop,
+                                                  sizeof(page_sizes_prop));
+    if (page_sizes_prop_size) {
+        _FDT((fdt_setprop(fdt, offset, "ibm,segment-page-sizes",
+                           page_sizes_prop, page_sizes_prop_size)));
+    }
+
+    _FDT((fdt_setprop_cell(fdt, offset, "ibm,chip-id",
+                                cs->cpu_index / cpus_per_socket)));
+
+    _FDT((fdt_setprop_cell(fdt, offset, "ibm,my-drc-index", drc_index)));
+
+    /* Build interrupt servers and gservers properties */
+    for (i = 0; i < smpt; i++) {
+        servers_prop[i] = cpu_to_be32(index + i);
+        /* Hack, direct the group queues back to cpu 0 */
+        gservers_prop[i*2] = cpu_to_be32(index + i);
+        gservers_prop[i*2 + 1] = 0;
+    }
+    _FDT(fdt_setprop(fdt, offset, "ibm,ppc-interrupt-server#s",
+                       servers_prop, sizeof(servers_prop)));
+    _FDT(fdt_setprop(fdt, offset, "ibm,ppc-interrupt-gserver#s",
+                      gservers_prop, sizeof(gservers_prop)));
+    _FDT(fdt_setprop(fdt, offset, "ibm,pft-size",
+                          pft_size_prop, sizeof(pft_size_prop)));
+
+    if (nb_numa_nodes > 1) {
+        _FDT(fdt_setprop(fdt, offset, "ibm,associativity", associativity,
+                          sizeof(associativity)));
+    }
+}
+
+static void spapr_cpu_hotplug_add(DeviceState *dev, CPUState *cs)
+{
+    PowerPCCPU *cpu = POWERPC_CPU(cs);
+    DeviceClass *dc = DEVICE_GET_CLASS(cs);
+    int id = ppc_get_vcpu_dt_id(cpu);
+    sPAPRDRConnector *drc =
+        spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, id);
+    sPAPRDRConnectorClass *drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
+    int drc_index = drck->get_index(drc);
+    void *fdt, *fdt_orig;
+    int offset, i;
+    char *nodename;
+
+    /* add OF node for CPU and required OF DT properties */
+    fdt_orig = g_malloc0(FDT_MAX_SIZE);
+    offset = fdt_create(fdt_orig, FDT_MAX_SIZE);
+    fdt_begin_node(fdt_orig, "");
+    fdt_end_node(fdt_orig);
+    fdt_finish(fdt_orig);
+
+    fdt = g_malloc0(FDT_MAX_SIZE);
+    fdt_open_into(fdt_orig, fdt, FDT_MAX_SIZE);
+
+    nodename = g_strdup_printf("%s@%x", dc->fw_name, id);
+
+    offset = fdt_add_subnode(fdt, offset, nodename);
+
+    /* Set NUMA node for the added CPU */
+    for (i = 0; i < nb_numa_nodes; i++) {
+        if (test_bit(cs->cpu_index, numa_info[i].node_cpu)) {
+            cs->numa_node = i;
+            break;
+        }
+    }
+
+    spapr_populate_cpu_dt(cs, fdt, offset, drc_index);
+    g_free(fdt_orig);
+    g_free(nodename);
+
+    drck->attach(drc, dev, fdt, offset, false);
+}
+
+static void spapr_cpu_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
+                            Error **errp)
+{
+    Error *local_err = NULL;
+    CPUState *cs = CPU(dev);
+    PowerPCCPU *cpu = POWERPC_CPU(cs);
+    sPAPRDRConnector *drc =
+        spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, cpu->cpu_dt_id);
+
+    /* TODO: Check if DR is enabled ? */
+    g_assert(drc);
+
+    spapr_cpu_reset(POWERPC_CPU(CPU(dev)));
+    spapr_cpu_hotplug_add(dev, cs);
+    spapr_hotplug_req_add_event(drc);
+    error_propagate(errp, local_err);
+    return;
+}
+
+static void spapr_machine_device_plug(HotplugHandler *hotplug_dev,
+                                      DeviceState *dev, Error **errp)
+{
+    if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
+        if (dev->hotplugged) {
+            spapr_cpu_plug(hotplug_dev, dev, errp);
+        }
+    }
+}
+
+static HotplugHandler *spapr_get_hotpug_handler(MachineState *machine,
+                                             DeviceState *dev)
+{
+    if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
+        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;
@@ -1759,6 +1958,9 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
     mc->default_boot_order = NULL;
     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;
     smc->dr_phb_enabled = false;
     smc->dr_cpu_enabled = false;
     smc->dr_lmb_enabled = false;
@@ -1778,6 +1980,7 @@ 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 434a75d..035d8c9 100644
--- a/hw/ppc/spapr_events.c
+++ b/hw/ppc/spapr_events.c
@@ -364,14 +364,16 @@ 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_CPU:
+        hp->hotplug_type = RTAS_LOG_V6_HP_TYPE_CPU;
+        break;
     default:
         /* skip notification for unknown connector types */
         g_free(new_hp);
diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
index 9c642a5..cf9d8d3 100644
--- a/target-ppc/translate_init.c
+++ b/target-ppc/translate_init.c
@@ -32,6 +32,7 @@
 #include "hw/qdev-properties.h"
 #include "hw/ppc/spapr.h"
 #include "hw/ppc/ppc.h"
+#include "sysemu/sysemu.h"
 
 //#define PPC_DUMP_CPU
 //#define PPC_DEBUG_SPR
@@ -8909,6 +8910,11 @@ static void ppc_cpu_realizefn(DeviceState *dev, Error **errp)
         return;
     }
 
+    if (cs->cpu_index >= max_cpus) {
+        error_setg(errp, "Can't have more CPUs, maxcpus limit reached");
+        return;
+    }
+
     cpu->cpu_dt_id = (cs->cpu_index / smp_threads) * max_smt
         + (cs->cpu_index % smp_threads);
 #endif
-- 
2.1.0