x86: move cpu hotplug from pc to x86

The cpu hotplug code handles the initialization of coldplugged cpus
too, so it is needed even in case cpu hotplug is not supported.

Move the code from pc to x86, so microvm can use it.

Move both plug and unplug to keep everything in one place, even
though microvm needs plug only.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Sergio Lopez <slp@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-id: 20200915120909.20838-16-kraxel@redhat.com

1 files changed, 271 insertions, 0 deletions

diff --git a/hw/i386/x86.c b/hw/i386/x86.c
index e2a5005..c2ea989 100644
--- a/hw/i386/x86.c
+++ b/hw/i386/x86.c
@@ -41,6 +41,7 @@
 #include "hw/i386/topology.h"
 #include "hw/i386/fw_cfg.h"
 #include "hw/intc/i8259.h"
+#include "hw/rtc/mc146818rtc.h"
 
 #include "hw/acpi/cpu_hotplug.h"
 #include "hw/irq.h"
@@ -137,6 +138,276 @@ void x86_cpus_init(X86MachineState *x86ms, int default_cpu_version)
     }
 }
 
+void x86_rtc_set_cpus_count(ISADevice *rtc, uint16_t cpus_count)
+{
+    if (cpus_count > 0xff) {
+        /*
+         * If the number of CPUs can't be represented in 8 bits, the
+         * BIOS must use "FW_CFG_NB_CPUS". Set RTC field to 0 just
+         * to make old BIOSes fail more predictably.
+         */
+        rtc_set_memory(rtc, 0x5f, 0);
+    } else {
+        rtc_set_memory(rtc, 0x5f, cpus_count - 1);
+    }
+}
+
+static int x86_apic_cmp(const void *a, const void *b)
+{
+   CPUArchId *apic_a = (CPUArchId *)a;
+   CPUArchId *apic_b = (CPUArchId *)b;
+
+   return apic_a->arch_id - apic_b->arch_id;
+}
+
+/*
+ * returns pointer to CPUArchId descriptor that matches CPU's apic_id
+ * in ms->possible_cpus->cpus, if ms->possible_cpus->cpus has no
+ * entry corresponding to CPU's apic_id returns NULL.
+ */
+CPUArchId *x86_find_cpu_slot(MachineState *ms, uint32_t id, int *idx)
+{
+    CPUArchId apic_id, *found_cpu;
+
+    apic_id.arch_id = id;
+    found_cpu = bsearch(&apic_id, ms->possible_cpus->cpus,
+        ms->possible_cpus->len, sizeof(*ms->possible_cpus->cpus),
+        x86_apic_cmp);
+    if (found_cpu && idx) {
+        *idx = found_cpu - ms->possible_cpus->cpus;
+    }
+    return found_cpu;
+}
+
+void x86_cpu_plug(HotplugHandler *hotplug_dev,
+                  DeviceState *dev, Error **errp)
+{
+    CPUArchId *found_cpu;
+    Error *local_err = NULL;
+    X86CPU *cpu = X86_CPU(dev);
+    X86MachineState *x86ms = X86_MACHINE(hotplug_dev);
+
+    if (x86ms->acpi_dev) {
+        hotplug_handler_plug(x86ms->acpi_dev, dev, &local_err);
+        if (local_err) {
+            goto out;
+        }
+    }
+
+    /* increment the number of CPUs */
+    x86ms->boot_cpus++;
+    if (x86ms->rtc) {
+        x86_rtc_set_cpus_count(x86ms->rtc, x86ms->boot_cpus);
+    }
+    if (x86ms->fw_cfg) {
+        fw_cfg_modify_i16(x86ms->fw_cfg, FW_CFG_NB_CPUS, x86ms->boot_cpus);
+    }
+
+    found_cpu = x86_find_cpu_slot(MACHINE(x86ms), cpu->apic_id, NULL);
+    found_cpu->cpu = OBJECT(dev);
+out:
+    error_propagate(errp, local_err);
+}
+
+void x86_cpu_unplug_request_cb(HotplugHandler *hotplug_dev,
+                               DeviceState *dev, Error **errp)
+{
+    int idx = -1;
+    X86CPU *cpu = X86_CPU(dev);
+    X86MachineState *x86ms = X86_MACHINE(hotplug_dev);
+
+    if (!x86ms->acpi_dev) {
+        error_setg(errp, "CPU hot unplug not supported without ACPI");
+        return;
+    }
+
+    x86_find_cpu_slot(MACHINE(x86ms), cpu->apic_id, &idx);
+    assert(idx != -1);
+    if (idx == 0) {
+        error_setg(errp, "Boot CPU is unpluggable");
+        return;
+    }
+
+    hotplug_handler_unplug_request(x86ms->acpi_dev, dev,
+                                   errp);
+}
+
+void x86_cpu_unplug_cb(HotplugHandler *hotplug_dev,
+                       DeviceState *dev, Error **errp)
+{
+    CPUArchId *found_cpu;
+    Error *local_err = NULL;
+    X86CPU *cpu = X86_CPU(dev);
+    X86MachineState *x86ms = X86_MACHINE(hotplug_dev);
+
+    hotplug_handler_unplug(x86ms->acpi_dev, dev, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    found_cpu = x86_find_cpu_slot(MACHINE(x86ms), cpu->apic_id, NULL);
+    found_cpu->cpu = NULL;
+    qdev_unrealize(dev);
+
+    /* decrement the number of CPUs */
+    x86ms->boot_cpus--;
+    /* Update the number of CPUs in CMOS */
+    x86_rtc_set_cpus_count(x86ms->rtc, x86ms->boot_cpus);
+    fw_cfg_modify_i16(x86ms->fw_cfg, FW_CFG_NB_CPUS, x86ms->boot_cpus);
+ out:
+    error_propagate(errp, local_err);
+}
+
+void x86_cpu_pre_plug(HotplugHandler *hotplug_dev,
+                      DeviceState *dev, Error **errp)
+{
+    int idx;
+    CPUState *cs;
+    CPUArchId *cpu_slot;
+    X86CPUTopoIDs topo_ids;
+    X86CPU *cpu = X86_CPU(dev);
+    CPUX86State *env = &cpu->env;
+    MachineState *ms = MACHINE(hotplug_dev);
+    X86MachineState *x86ms = X86_MACHINE(hotplug_dev);
+    unsigned int smp_cores = ms->smp.cores;
+    unsigned int smp_threads = ms->smp.threads;
+    X86CPUTopoInfo topo_info;
+
+    if (!object_dynamic_cast(OBJECT(cpu), ms->cpu_type)) {
+        error_setg(errp, "Invalid CPU type, expected cpu type: '%s'",
+                   ms->cpu_type);
+        return;
+    }
+
+    init_topo_info(&topo_info, x86ms);
+
+    env->nr_dies = x86ms->smp_dies;
+
+    /*
+     * If APIC ID is not set,
+     * set it based on socket/die/core/thread properties.
+     */
+    if (cpu->apic_id == UNASSIGNED_APIC_ID) {
+        int max_socket = (ms->smp.max_cpus - 1) /
+                                smp_threads / smp_cores / x86ms->smp_dies;
+
+        /*
+         * die-id was optional in QEMU 4.0 and older, so keep it optional
+         * if there's only one die per socket.
+         */
+        if (cpu->die_id < 0 && x86ms->smp_dies == 1) {
+            cpu->die_id = 0;
+        }
+
+        if (cpu->socket_id < 0) {
+            error_setg(errp, "CPU socket-id is not set");
+            return;
+        } else if (cpu->socket_id > max_socket) {
+            error_setg(errp, "Invalid CPU socket-id: %u must be in range 0:%u",
+                       cpu->socket_id, max_socket);
+            return;
+        }
+        if (cpu->die_id < 0) {
+            error_setg(errp, "CPU die-id is not set");
+            return;
+        } else if (cpu->die_id > x86ms->smp_dies - 1) {
+            error_setg(errp, "Invalid CPU die-id: %u must be in range 0:%u",
+                       cpu->die_id, x86ms->smp_dies - 1);
+            return;
+        }
+        if (cpu->core_id < 0) {
+            error_setg(errp, "CPU core-id is not set");
+            return;
+        } else if (cpu->core_id > (smp_cores - 1)) {
+            error_setg(errp, "Invalid CPU core-id: %u must be in range 0:%u",
+                       cpu->core_id, smp_cores - 1);
+            return;
+        }
+        if (cpu->thread_id < 0) {
+            error_setg(errp, "CPU thread-id is not set");
+            return;
+        } else if (cpu->thread_id > (smp_threads - 1)) {
+            error_setg(errp, "Invalid CPU thread-id: %u must be in range 0:%u",
+                       cpu->thread_id, smp_threads - 1);
+            return;
+        }
+
+        topo_ids.pkg_id = cpu->socket_id;
+        topo_ids.die_id = cpu->die_id;
+        topo_ids.core_id = cpu->core_id;
+        topo_ids.smt_id = cpu->thread_id;
+        cpu->apic_id = x86_apicid_from_topo_ids(&topo_info, &topo_ids);
+    }
+
+    cpu_slot = x86_find_cpu_slot(MACHINE(x86ms), cpu->apic_id, &idx);
+    if (!cpu_slot) {
+        MachineState *ms = MACHINE(x86ms);
+
+        x86_topo_ids_from_apicid(cpu->apic_id, &topo_info, &topo_ids);
+        error_setg(errp,
+            "Invalid CPU [socket: %u, die: %u, core: %u, thread: %u] with"
+            " APIC ID %" PRIu32 ", valid index range 0:%d",
+            topo_ids.pkg_id, topo_ids.die_id, topo_ids.core_id, topo_ids.smt_id,
+            cpu->apic_id, ms->possible_cpus->len - 1);
+        return;
+    }
+
+    if (cpu_slot->cpu) {
+        error_setg(errp, "CPU[%d] with APIC ID %" PRIu32 " exists",
+                   idx, cpu->apic_id);
+        return;
+    }
+
+    /* if 'address' properties socket-id/core-id/thread-id are not set, set them
+     * so that machine_query_hotpluggable_cpus would show correct values
+     */
+    /* TODO: move socket_id/core_id/thread_id checks into x86_cpu_realizefn()
+     * once -smp refactoring is complete and there will be CPU private
+     * CPUState::nr_cores and CPUState::nr_threads fields instead of globals */
+    x86_topo_ids_from_apicid(cpu->apic_id, &topo_info, &topo_ids);
+    if (cpu->socket_id != -1 && cpu->socket_id != topo_ids.pkg_id) {
+        error_setg(errp, "property socket-id: %u doesn't match set apic-id:"
+            " 0x%x (socket-id: %u)", cpu->socket_id, cpu->apic_id,
+            topo_ids.pkg_id);
+        return;
+    }
+    cpu->socket_id = topo_ids.pkg_id;
+
+    if (cpu->die_id != -1 && cpu->die_id != topo_ids.die_id) {
+        error_setg(errp, "property die-id: %u doesn't match set apic-id:"
+            " 0x%x (die-id: %u)", cpu->die_id, cpu->apic_id, topo_ids.die_id);
+        return;
+    }
+    cpu->die_id = topo_ids.die_id;
+
+    if (cpu->core_id != -1 && cpu->core_id != topo_ids.core_id) {
+        error_setg(errp, "property core-id: %u doesn't match set apic-id:"
+            " 0x%x (core-id: %u)", cpu->core_id, cpu->apic_id,
+            topo_ids.core_id);
+        return;
+    }
+    cpu->core_id = topo_ids.core_id;
+
+    if (cpu->thread_id != -1 && cpu->thread_id != topo_ids.smt_id) {
+        error_setg(errp, "property thread-id: %u doesn't match set apic-id:"
+            " 0x%x (thread-id: %u)", cpu->thread_id, cpu->apic_id,
+            topo_ids.smt_id);
+        return;
+    }
+    cpu->thread_id = topo_ids.smt_id;
+
+    if (hyperv_feat_enabled(cpu, HYPERV_FEAT_VPINDEX) &&
+        !kvm_hv_vpindex_settable()) {
+        error_setg(errp, "kernel doesn't allow setting HyperV VP_INDEX");
+        return;
+    }
+
+    cs = CPU(cpu);
+    cs->cpu_index = idx;
+
+    numa_cpu_pre_plug(cpu_slot, dev, errp);
+}
+
 CpuInstanceProperties
 x86_cpu_index_to_props(MachineState *ms, unsigned cpu_index)
 {