Steve Sistare <steven.sist...@oracle.com> writes:
> Add the only-migratable-modes option as a generalization of only-migratable.
> Only devices that support all requested modes are allowed.
>
> Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
> ---
> include/migration/misc.h | 3 +++
> include/sysemu/sysemu.h | 1 -
> migration/migration-hmp-cmds.c | 26 +++++++++++++++++++++++++-
> migration/migration.c | 22 +++++++++++++++++-----
> migration/savevm.c | 2 +-
> qemu-options.hx | 16 ++++++++++++++--
> system/globals.c | 1 -
> system/vl.c | 13 ++++++++++++-
> target/s390x/cpu_models.c | 4 +++-
> 9 files changed, 75 insertions(+), 13 deletions(-)
>
> diff --git a/include/migration/misc.h b/include/migration/misc.h
> index 5b963ba..3ad2cd9 100644
> --- a/include/migration/misc.h
> +++ b/include/migration/misc.h
> @@ -119,6 +119,9 @@ bool migration_incoming_postcopy_advised(void);
> /* True if background snapshot is active */
> bool migration_in_bg_snapshot(void);
>
> +void migration_set_required_mode(MigMode mode);
> +bool migration_mode_required(MigMode mode);
> +
> /* migration/block-dirty-bitmap.c */
> void dirty_bitmap_mig_init(void);
>
> diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
> index 5b4397e..0a9c4b4 100644
> --- a/include/sysemu/sysemu.h
> +++ b/include/sysemu/sysemu.h
> @@ -8,7 +8,6 @@
>
> /* vl.c */
>
> -extern int only_migratable;
> extern const char *qemu_name;
> extern QemuUUID qemu_uuid;
> extern bool qemu_uuid_set;
> diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
> index 414c7e8..ca913b7 100644
> --- a/migration/migration-hmp-cmds.c
> +++ b/migration/migration-hmp-cmds.c
> @@ -16,6 +16,7 @@
> #include "qemu/osdep.h"
> #include "block/qapi.h"
> #include "migration/snapshot.h"
> +#include "migration/misc.h"
> #include "monitor/hmp.h"
> #include "monitor/monitor.h"
> #include "qapi/error.h"
> @@ -33,6 +34,28 @@
> #include "options.h"
> #include "migration.h"
>
> +static void migration_dump_modes(Monitor *mon)
> +{
> + int mode, n = 0;
> +
> + monitor_printf(mon, "only-migratable-modes: ");
> +
> + for (mode = 0; mode < MIG_MODE__MAX; mode++) {
> + if (migration_mode_required(mode)) {
> + if (n++) {
> + monitor_printf(mon, ",");
> + }
> + monitor_printf(mon, "%s", MigMode_str(mode));
> + }
> + }
> +
> + if (!n) {
> + monitor_printf(mon, "none\n");
> + } else {
> + monitor_printf(mon, "\n");
> + }
> +}
> +
> static void migration_global_dump(Monitor *mon)
> {
> MigrationState *ms = migrate_get_current();
> @@ -41,7 +64,7 @@ static void migration_global_dump(Monitor *mon)
> monitor_printf(mon, "store-global-state: %s\n",
> ms->store_global_state ? "on" : "off");
> monitor_printf(mon, "only-migratable: %s\n",
> - only_migratable ? "on" : "off");
> + migration_mode_required(MIG_MODE_NORMAL) ? "on" : "off");
> monitor_printf(mon, "send-configuration: %s\n",
> ms->send_configuration ? "on" : "off");
> monitor_printf(mon, "send-section-footer: %s\n",
> @@ -50,6 +73,7 @@ static void migration_global_dump(Monitor *mon)
> ms->decompress_error_check ? "on" : "off");
> monitor_printf(mon, "clear-bitmap-shift: %u\n",
> ms->clear_bitmap_shift);
> + migration_dump_modes(mon);
> }
>
> void hmp_info_migrate(Monitor *mon, const QDict *qdict)
> diff --git a/migration/migration.c b/migration/migration.c
> index 4984dee..5535b84 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -1719,17 +1719,29 @@ static bool is_busy(Error **reasonp, Error **errp)
> return false;
> }
>
> -static bool is_only_migratable(Error **reasonp, Error **errp, int modes)
> +static int migration_modes_required;
> +
> +void migration_set_required_mode(MigMode mode)
> +{
> + migration_modes_required |= BIT(mode);
> +}
> +
> +bool migration_mode_required(MigMode mode)
> +{
> + return !!(migration_modes_required & BIT(mode));
> +}
> +
> +static bool modes_are_required(Error **reasonp, Error **errp, int modes)
> {
> ERRP_GUARD();
>
> - if (only_migratable && (modes & BIT(MIG_MODE_NORMAL))) {
> + if (migration_modes_required & modes) {
> error_propagate_prepend(errp, *reasonp,
> - "disallowing migration blocker "
> - "(--only-migratable) for: ");
> + "-only-migratable{-modes} specified, but:
> ");
extra space before 'specified'
> *reasonp = NULL;
> return true;
> }
> +
> return false;
> }
>
> @@ -1783,7 +1795,7 @@ int migrate_add_blocker_modes(Error **reasonp, Error
> **errp, MigMode mode, ...)
> modes = get_modes(mode, ap);
> va_end(ap);
>
> - if (is_only_migratable(reasonp, errp, modes)) {
> + if (modes_are_required(reasonp, errp, modes)) {
> return -EACCES;
> } else if (is_busy(reasonp, errp)) {
> return -EBUSY;
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 6087c3a..e53ac84 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -3585,7 +3585,7 @@ void vmstate_register_ram_global(MemoryRegion *mr)
> bool vmstate_check_only_migratable(const VMStateDescription *vmsd)
> {
> /* check needed if --only-migratable is specified */
> - if (!only_migratable) {
> + if (!migration_mode_required(MIG_MODE_NORMAL)) {
> return true;
> }
>
> diff --git a/qemu-options.hx b/qemu-options.hx
> index f0dfda5..946d731 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -4807,8 +4807,20 @@ DEF("only-migratable", 0, QEMU_OPTION_only_migratable,
> \
> "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL)
> SRST
> ``-only-migratable``
> - Only allow migratable devices. Devices will not be allowed to enter
> - an unmigratable state.
> + Only allow devices that can migrate using normal mode. Devices will not
> + be allowed to enter an unmigratable state.
What's a "normal" mode is what people will ask. I don't think we need to
expose this. This option never had anything to do with "modes" and I
think we can keep it this way. See below...
> +ERST
> +
> +DEF("only-migratable-modes", HAS_ARG, QEMU_OPTION_only_migratable_modes, \
> + "-only-migratable-modes mode1[,...]\n"
> + " allow only devices that are migratable using mode(s)\n",
> + QEMU_ARCH_ALL)
> +SRST
> +``-only-migratable-modes mode1[,...]``
> + Only allow devices which are migratable using all modes in the list,
> + which guarantees that migration will not fail due to a blocker.
> + If both only-migratable-modes and only-migratable are specified,
> + or are specified multiple times, then the required modes accumulate.
> ERST
>
> DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
> diff --git a/system/globals.c b/system/globals.c
> index e353584..fdc263e 100644
> --- a/system/globals.c
> +++ b/system/globals.c
> @@ -48,7 +48,6 @@ const char *qemu_name;
> unsigned int nb_prom_envs;
> const char *prom_envs[MAX_PROM_ENVS];
> uint8_t *boot_splash_filedata;
> -int only_migratable; /* turn it off unless user states otherwise */
> int icount_align_option;
>
> /* The bytes in qemu_uuid are in the order specified by RFC4122, _not_ in the
> diff --git a/system/vl.c b/system/vl.c
> index b76881e..7e73be9 100644
> --- a/system/vl.c
> +++ b/system/vl.c
> @@ -3458,7 +3458,18 @@ void qemu_init(int argc, char **argv)
> incoming = optarg;
> break;
> case QEMU_OPTION_only_migratable:
> - only_migratable = 1;
> + migration_set_required_mode(MIG_MODE_NORMAL);
...from the point of view of user intent, I think this should be
MIG_MODE_ALL. If I have this option set I never want to see a blocker,
period. That's not a change in behavior because the mode has to be
explicitly selected anyway.
> + break;
> + case QEMU_OPTION_only_migratable_modes:
> + {
> + int i, mode;
> + g_autofree char **words = g_strsplit(optarg, ",", -1);
> + for (i = 0; words[i]; i++) {
> + mode = qapi_enum_parse(&MigMode_lookup, words[i], -1,
> + &error_fatal);
> + migration_set_required_mode(mode);
This option can be used to refine the modes being considered, it should
take precedence if both are present.
> + }
> + }
> break;
> case QEMU_OPTION_nodefaults:
> has_defaults = 0;
> diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
> index 8ed3bb6..42ad160 100644
> --- a/target/s390x/cpu_models.c
> +++ b/target/s390x/cpu_models.c
> @@ -16,6 +16,7 @@
> #include "kvm/kvm_s390x.h"
> #include "sysemu/kvm.h"
> #include "sysemu/tcg.h"
> +#include "migration/misc.h"
> #include "qapi/error.h"
> #include "qemu/error-report.h"
> #include "qapi/visitor.h"
> @@ -526,7 +527,8 @@ static void check_compatibility(const S390CPUModel
> *max_model,
> }
>
> #ifndef CONFIG_USER_ONLY
> - if (only_migratable && test_bit(S390_FEAT_UNPACK, model->features)) {
> + if (migration_mode_required(MIG_MODE_NORMAL) &&
> + test_bit(S390_FEAT_UNPACK, model->features)) {
> error_setg(errp, "The unpack facility is not compatible with "
> "the --only-migratable option. You must remove either "
> "the 'unpack' facility or the --only-migratable option");
