On Fri, Jun 09, 2017 at 11:48:59AM +0800, Peter Xu wrote:
> Put it into MigrationState then we can use the properties to specify
> whether to enable storing global state.
>
> Removing global_state_set_optional() since now we can use HW_COMPAT_2_3
> for x86/power in general, and the register_compat_prop() for xen_init().
>
> Signed-off-by: Peter Xu <pet...@redhat.com>
> ---
> hw/i386/pc_piix.c | 1 -
> hw/ppc/spapr.c | 1 -
> hw/xen/xen-common.c | 8 +++++++-
> include/hw/compat.h | 4 ++++
> include/migration/migration.h | 7 ++++++-
> migration/migration.c | 24 ++++++++++++++++--------
> 6 files changed, 33 insertions(+), 12 deletions(-)
>
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 2234bd0..c83cec5 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -317,7 +317,6 @@ static void pc_compat_2_3(MachineState *machine)
> if (kvm_enabled()) {
> pcms->smm = ON_OFF_AUTO_OFF;
> }
> - global_state_set_optional();
> savevm_skip_configuration();
> }
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index ab3aab1..3e78bb9 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -3593,7 +3593,6 @@ static void
> spapr_machine_2_3_instance_options(MachineState *machine)
> {
> spapr_machine_2_4_instance_options(machine);
> savevm_skip_section_footers();
> - global_state_set_optional();
> savevm_skip_configuration();
> }
This is a good thing: makes the migration behavior of the
machine-types introspectable in compat_props.
I suggest moving this part (and all the rest except the new
register_compat_prop() call below) to a separate patch, because
it is an improvement on its own.
>
> diff --git a/hw/xen/xen-common.c b/hw/xen/xen-common.c
> index 0bed577..8240d50 100644
> --- a/hw/xen/xen-common.c
> +++ b/hw/xen/xen-common.c
> @@ -138,7 +138,13 @@ static int xen_init(MachineState *ms)
> }
> qemu_add_vm_change_state_handler(xen_change_state_handler, NULL);
>
> - global_state_set_optional();
> + /*
> + * TODO: make sure global MigrationState has not yet been created
> + * (otherwise the compat trick won't work). For now we are in
> + * configure_accelerator() so we are mostly good. Better to
> + * confirm that in the future.
> + */
So, this makes accelerator initialization very sensitive to
ordering.
> + register_compat_prop("migration", "store-global-state", "off");
It's already hard to track down machine-type stuff that is
initialized at machine->init() time but it's not introspectable,
let's not do the same mistake with accelerators.
Can't this be solved by a AcceleratorClass::global_props field,
so we are sure there's a single place in the code where globals
are registered? (Currently, they are all registered by the few
lines around the machine_register_compat_props() call in main()).
I think I see other use cases for a new
AcceleratorClass::global_props field. e.g.: replacing
kvm_default_props and tcg_default_props in target/i386/cpu.c.
> savevm_skip_configuration();
> savevm_skip_section_footers();
>
> diff --git a/include/hw/compat.h b/include/hw/compat.h
> index 400c64b..5b5c8de 100644
> --- a/include/hw/compat.h
> +++ b/include/hw/compat.h
> @@ -177,6 +177,10 @@
> .driver = TYPE_PCI_DEVICE,\
> .property = "x-pcie-lnksta-dllla",\
> .value = "off",\
> + },{\
> + .driver = "migration",\
> + .property = "store-global-state",\
> + .value = "off",\
> },
>
> #define HW_COMPAT_2_2 \
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index bd0186c..d3ec719 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -162,6 +162,12 @@ struct MigrationState
> /* Do we have to clean up -b/-i from old migrate parameters */
> /* This feature is deprecated and will be removed */
> bool must_remove_block_options;
> +
> + /*
> + * Global switch on whether we need to store the global state
> + * during migration.
> + */
> + bool store_global_state;
> };
>
> void migrate_set_state(int *state, int old_state, int new_state);
> @@ -240,7 +246,6 @@ size_t ram_control_save_page(QEMUFile *f, ram_addr_t
> block_offset,
>
> void savevm_skip_section_footers(void);
> void register_global_state(void);
> -void global_state_set_optional(void);
> void savevm_skip_configuration(void);
> int global_state_store(void);
> void global_state_store_running(void);
> diff --git a/migration/migration.c b/migration/migration.c
> index 98b77e2..79d886c 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -138,13 +138,13 @@ void migration_incoming_state_destroy(void)
>
>
> typedef struct {
> - bool optional;
> uint32_t size;
> uint8_t runstate[100];
> RunState state;
> bool received;
> } GlobalState;
>
> +/* This is only used if MigrationState.store_global_state is set. */
> static GlobalState global_state;
>
> int global_state_store(void)
> @@ -175,19 +175,13 @@ static RunState global_state_get_runstate(void)
> return global_state.state;
> }
>
> -void global_state_set_optional(void)
> -{
> - global_state.optional = true;
> -}
> -
> static bool global_state_needed(void *opaque)
> {
> GlobalState *s = opaque;
> char *runstate = (char *)s->runstate;
>
> /* If it is not optional, it is mandatory */
> -
> - if (s->optional == false) {
> + if (migrate_get_current()->store_global_state) {
> return true;
> }
>
> @@ -2107,6 +2101,19 @@ void migrate_fd_connect(MigrationState *s)
> s->migration_thread_running = true;
> }
>
> +static Property migration_properties[] = {
> + DEFINE_PROP_BOOL("store-global-state", MigrationState,
> + store_global_state, true),
> + DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static void migration_class_init(ObjectClass *klass, void *data)
> +{
> + DeviceClass *dc = DEVICE_CLASS(klass);
> +
> + dc->props = migration_properties;
> +}
> +
> static void migration_instance_init(Object *obj)
> {
> MigrationState *ms = MIGRATION_OBJ(obj);
> @@ -2131,6 +2138,7 @@ static void migration_instance_init(Object *obj)
> static const TypeInfo migration_type = {
> .name = TYPE_MIGRATION,
> .parent = TYPE_DEVICE,
> + .class_init = migration_class_init,
> .class_size = sizeof(MigrationClass),
> .instance_size = sizeof(MigrationState),
> .instance_init = migration_instance_init,
> --
> 2.7.4
>
>
--
Eduardo
