On Tue, 12 Jul 2016 15:07:09 +1000
David Gibson <da...@gibson.dropbear.id.au> wrote:
> On Mon, Jul 11, 2016 at 03:42:29PM +0200, Igor Mammedov wrote:
> > this approach i I preffer as it uses less per machine migration glue
> > and follows typical compat pattern for devices
> >
> > Signed-off-by: Igor Mammedov <imamm...@redhat.com>
> > Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.com>
>
> After our IRC discussion last night, I prefer this version as well.
> We can definitely work with this on Power as well.
>
> Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>
Bharata,
Could you take this patch but strip out PC parts which were meant
as usage example only?
I'll post a separate PC patch on top of it as part of or on top of
cpu-hotplug for PC, as that series changes pc.c significantly and
resulting PC part of patch will look a bit simpler/different.
>
> One query regarding the x86 specific implementation below, though.
>
> > ---
> > exec.c | 7 +++++--
> > hw/i386/pc.c | 10 +++++++---
> > include/hw/compat.h | 6 +++++-
> > include/qom/cpu.h | 3 +++
> > qom/cpu.c | 13 +++++++++++++
> > 5 files changed, 33 insertions(+), 6 deletions(-)
> >
> > diff --git a/exec.c b/exec.c
> > index 0122ef7..79e1dcb 100644
> > --- a/exec.c
> > +++ b/exec.c
> > @@ -670,6 +670,7 @@ void cpu_exec_init(CPUState *cpu, Error **errp)
> > {
> > CPUClass *cc = CPU_GET_CLASS(cpu);
> > Error *local_err = NULL;
> > + int migration_id;
> >
> > cpu->as = NULL;
> > cpu->num_ases = 0;
> > @@ -708,11 +709,13 @@ void cpu_exec_init(CPUState *cpu, Error **errp)
> > (void) cc;
> > cpu_list_unlock();
> > #else
> > + migration_id = cc->use_migration_id > 0 ?
> > + cpu->migration_id : cpu->cpu_index;
> > if (qdev_get_vmsd(DEVICE(cpu)) == NULL) {
> > - vmstate_register(NULL, cpu->cpu_index, &vmstate_cpu_common, cpu);
> > + vmstate_register(NULL, migration_id, &vmstate_cpu_common, cpu);
> > }
> > if (cc->vmsd != NULL) {
> > - vmstate_register(NULL, cpu->cpu_index, cc->vmsd, cpu);
> > + vmstate_register(NULL, migration_id, cc->vmsd, cpu);
> > }
> > #endif
> > }
> > diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> > index cd1745e..f041279 100644
> > --- a/hw/i386/pc.c
> > +++ b/hw/i386/pc.c
> > @@ -1040,9 +1040,10 @@ void pc_acpi_smi_interrupt(void *opaque, int irq,
> > int level)
> > }
> >
> > static X86CPU *pc_new_cpu(const char *cpu_model, int64_t apic_id,
> > - Error **errp)
> > + Error **errp, int migration_id)
> > {
> > X86CPU *cpu = NULL;
> > + CPUState *cs = CPU(cpu);
> > Error *local_err = NULL;
> >
>
> Any reason not to re-use the apic_id as the migration_id? It's 64-bit
> here which is no good, but apic_id_t is defined as uint32_t elsewhere,
> so is that just a bug with the function signature?
It could be apic_id but I chose to use possible_cpus index to make code
similar as much as possible so that when I start adding cpu-hotplug to ARM
it would be possible to reuse some of x86 code that could be generalized
shared between both archs.
> > cpu = cpu_x86_create(cpu_model, &local_err);
> > @@ -1050,6 +1051,7 @@ static X86CPU *pc_new_cpu(const char *cpu_model,
> > int64_t apic_id,
> > goto out;
> > }
> >
> > + cs->migration_id = migration_id;
> > object_property_set_int(OBJECT(cpu), apic_id, "apic-id", &local_err);
> > object_property_set_bool(OBJECT(cpu), true, "realized", &local_err);
> >
> > @@ -1093,7 +1095,7 @@ void pc_hot_add_cpu(const int64_t id, Error **errp)
> > return;
> > }
> >
> > - cpu = pc_new_cpu(machine->cpu_model, apic_id, &local_err);
> > + cpu = pc_new_cpu(machine->cpu_model, apic_id, &local_err, id);
> > if (local_err) {
> > error_propagate(errp, local_err);
> > return;
> > @@ -1137,7 +1139,7 @@ void pc_cpus_init(PCMachineState *pcms)
> > pcms->possible_cpus->len++;
> > if (i < smp_cpus) {
> > cpu = pc_new_cpu(machine->cpu_model,
> > x86_cpu_apic_id_from_index(i),
> > - &error_fatal);
> > + &error_fatal, i);
> > pcms->possible_cpus->cpus[i].cpu = CPU(cpu);
> > object_unref(OBJECT(cpu));
> > }
> > @@ -2012,7 +2014,9 @@ static void pc_machine_class_init(ObjectClass *oc,
> > void *data)
> > PCMachineClass *pcmc = PC_MACHINE_CLASS(oc);
> > HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(oc);
> > NMIClass *nc = NMI_CLASS(oc);
> > + CPUClass *cc = CPU_CLASS(object_class_by_name(TYPE_CPU));
> >
> > + cc->use_migration_id = true;
> > pcmc->get_hotplug_handler = mc->get_hotplug_handler;
> > pcmc->pci_enabled = true;
> > pcmc->has_acpi_build = true;
> > diff --git a/include/hw/compat.h b/include/hw/compat.h
> > index 636befe..a66e80d 100644
> > --- a/include/hw/compat.h
> > +++ b/include/hw/compat.h
> > @@ -2,7 +2,11 @@
> > #define HW_COMPAT_H
> >
> > #define HW_COMPAT_2_6 \
> > - /* empty */
> > + { \
> > + .driver = TYPE_CPU, \
> > + .property = "use-migration-id", \
> > + .value = "off", \
> > + },
> >
> > #define HW_COMPAT_2_5 \
> > {\
> > diff --git a/include/qom/cpu.h b/include/qom/cpu.h
> > index 32f3af3..a29a2c9 100644
> > --- a/include/qom/cpu.h
> > +++ b/include/qom/cpu.h
> > @@ -177,6 +177,8 @@ typedef struct CPUClass {
> > void *opaque);
> >
> > const struct VMStateDescription *vmsd;
> > + int use_migration_id;
> > +
> > int gdb_num_core_regs;
> > const char *gdb_core_xml_file;
> > gchar * (*gdb_arch_name)(CPUState *cpu);
> > @@ -360,6 +362,7 @@ struct CPUState {
> > (absolute value) offset as small as possible. This reduces code
> > size, especially for hosts without large memory offsets. */
> > uint32_t tcg_exit_req;
> > + int migration_id;
>
> Not really in scope for this patch, but I do wonder if
> vmstate_register() should actually take a uint32_t instead of an int,
> since that's what it is on the wire, IIUC.
I think vmstate_register() uses -1 as a way to detect if it should
do instance_id auto assignment.
Any way I'll leave answer to this this question to migration experts.
>
> > };
> >
> > QTAILQ_HEAD(CPUTailQ, CPUState);
> > diff --git a/qom/cpu.c b/qom/cpu.c
> > index 751e992..3eb48b9 100644
> > --- a/qom/cpu.c
> > +++ b/qom/cpu.c
> > @@ -342,11 +342,24 @@ static int64_t cpu_common_get_arch_id(CPUState *cpu)
> > return cpu->cpu_index;
> > }
> >
> > +static void cpu_common_set_use_migration_id(Object *obj, bool value,
> > + Error **err)
> > +{
> > + CPUClass *cc = CPU_GET_CLASS(obj);
> > + cc->use_migration_id = value ? 1 : 0;
> > +}
> > +
> > static void cpu_class_init(ObjectClass *klass, void *data)
> > {
> > DeviceClass *dc = DEVICE_CLASS(klass);
> > CPUClass *k = CPU_CLASS(klass);
> >
> > + k->use_migration_id = -1;
> > + object_class_property_add_bool(klass, "use-migration-id",
> > + NULL,
> > + cpu_common_set_use_migration_id,
> > + &error_abort);
> > +
> > k->class_by_name = cpu_common_class_by_name;
> > k->parse_features = cpu_common_parse_features;
> > k->reset = cpu_common_reset;
>
