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From: Steven Sistare <steven.sistare@oracle.com>
To: Fabiano Rosas <farosas@suse.de>, qemu-devel@nongnu.org
Cc: Peter Xu <peterx@redhat.com>,
	David Hildenbrand <david@redhat.com>,
	Igor Mammedov <imammedo@redhat.com>,
	Eduardo Habkost <eduardo@habkost.net>,
	Marcel Apfelbaum <marcel.apfelbaum@gmail.com>,
	Philippe Mathieu-Daude <philmd@linaro.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	"Daniel P. Berrange" <berrange@redhat.com>,
	Markus Armbruster <armbru@redhat.com>
Subject: Re: [PATCH V1 26/26] migration: only-migratable-modes
Date: Mon, 13 May 2024 15:48:54 -0400	[thread overview]
Message-ID: <9e5a8874-84c3-4c7b-aa0e-6d01ea6a63de@oracle.com> (raw)
In-Reply-To: <87ikzmkdaq.fsf@suse.de>

On 5/9/2024 3:14 PM, Fabiano Rosas wrote:
> Steve Sistare <steven.sistare@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.sistare@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'

Will fix, thanks.

>>           *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...

We now have a mode parameter and enum MigMode which includes normal, and is
documented in qapi.

>> +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 only-migratable applies to all modes, then:
If a user only intends to use mode A, then a blocker for mode B will terminate
qemu.  Not good.

Defining only-migratable to apply to normal mode is the backwards-compatible
solution.

- Steve

> 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");


  reply	other threads:[~2024-05-13 19:54 UTC|newest]

Thread overview: 113+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-29 15:55 [PATCH V1 00/26] Live update: cpr-exec Steve Sistare
2024-04-29 15:55 ` [PATCH V1 01/26] oslib: qemu_clear_cloexec Steve Sistare
2024-05-06 23:27   ` Fabiano Rosas
2024-05-07  8:56     ` Daniel P. Berrangé
2024-05-07 13:54       ` Fabiano Rosas
2024-04-29 15:55 ` [PATCH V1 02/26] vl: helper to request re-exec Steve Sistare
2024-04-29 15:55 ` [PATCH V1 03/26] migration: SAVEVM_FOREACH Steve Sistare
2024-05-06 23:17   ` Fabiano Rosas
2024-05-13 19:27     ` Steven Sistare
2024-05-27 18:14       ` Peter Xu
2024-04-29 15:55 ` [PATCH V1 04/26] migration: delete unused parameter mis Steve Sistare
2024-05-06 21:50   ` Fabiano Rosas
2024-05-27 18:02   ` Peter Xu
2024-04-29 15:55 ` [PATCH V1 05/26] migration: precreate vmstate Steve Sistare
2024-05-07 21:02   ` Fabiano Rosas
2024-05-13 19:28     ` Steven Sistare
2024-05-24 13:56   ` Fabiano Rosas
2024-05-27 18:16   ` Peter Xu
2024-05-28 15:09     ` Steven Sistare via
2024-05-29 18:39       ` Peter Xu
2024-05-30 17:04         ` Steven Sistare via
2024-04-29 15:55 ` [PATCH V1 06/26] migration: precreate vmstate for exec Steve Sistare
2024-05-06 23:34   ` Fabiano Rosas
2024-05-13 19:28     ` Steven Sistare
2024-05-13 21:21       ` Fabiano Rosas
2024-04-29 15:55 ` [PATCH V1 07/26] migration: VMStateId Steve Sistare
2024-05-07 21:03   ` Fabiano Rosas
2024-05-27 18:20   ` Peter Xu
2024-05-28 15:10     ` Steven Sistare via
2024-05-28 17:44       ` Peter Xu
2024-05-29 17:30         ` Steven Sistare via
2024-05-29 18:53           ` Peter Xu
2024-05-30 17:11             ` Steven Sistare via
2024-05-30 18:03               ` Peter Xu
2024-04-29 15:55 ` [PATCH V1 08/26] migration: vmstate_info_void_ptr Steve Sistare
2024-05-07 21:33   ` Fabiano Rosas
2024-05-27 18:31   ` Peter Xu
2024-05-28 15:10     ` Steven Sistare via
2024-05-28 18:21       ` Peter Xu
2024-05-29 17:30         ` Steven Sistare via
2024-04-29 15:55 ` [PATCH V1 09/26] migration: vmstate_register_named Steve Sistare
2024-05-09 14:19   ` Fabiano Rosas
2024-05-09 14:32     ` Fabiano Rosas
2024-05-13 19:29       ` Steven Sistare
2024-04-29 15:55 ` [PATCH V1 10/26] migration: vmstate_unregister_named Steve Sistare
2024-04-29 15:55 ` [PATCH V1 11/26] migration: vmstate_register at init time Steve Sistare
2024-04-29 15:55 ` [PATCH V1 12/26] migration: vmstate factory object Steve Sistare
2024-04-29 15:55 ` [PATCH V1 13/26] physmem: ram_block_create Steve Sistare
2024-05-13 18:37   ` Fabiano Rosas
2024-05-13 19:30     ` Steven Sistare
2024-04-29 15:55 ` [PATCH V1 14/26] physmem: hoist guest_memfd creation Steve Sistare
2024-04-29 15:55 ` [PATCH V1 15/26] physmem: hoist host memory allocation Steve Sistare
2024-04-29 15:55 ` [PATCH V1 16/26] physmem: set ram block idstr earlier Steve Sistare
2024-04-29 15:55 ` [PATCH V1 17/26] machine: memfd-alloc option Steve Sistare
2024-05-28 21:12   ` Peter Xu
2024-05-29 17:31     ` Steven Sistare via
2024-05-29 19:14       ` Peter Xu
2024-05-30 17:11         ` Steven Sistare via
2024-05-30 18:14           ` Peter Xu
2024-05-31 19:32             ` Steven Sistare via
2024-04-29 15:55 ` [PATCH V1 18/26] migration: cpr-exec-args parameter Steve Sistare
2024-05-02 12:23   ` Markus Armbruster
2024-05-02 16:00     ` Steven Sistare
2024-05-21  8:13   ` Daniel P. Berrangé
2024-04-29 15:55 ` [PATCH V1 19/26] physmem: preserve ram blocks for cpr Steve Sistare
2024-05-28 21:44   ` Peter Xu
2024-05-29 17:31     ` Steven Sistare via
2024-05-29 19:25       ` Peter Xu
2024-05-30 17:12         ` Steven Sistare via
2024-05-30 18:39           ` Peter Xu
2024-05-31 19:32             ` Steven Sistare via
2024-04-29 15:55 ` [PATCH V1 20/26] migration: cpr-exec mode Steve Sistare
2024-05-02 12:23   ` Markus Armbruster
2024-05-02 16:00     ` Steven Sistare
2024-05-03  6:26       ` Markus Armbruster
2024-05-21  8:20   ` Daniel P. Berrangé
2024-05-24 14:58   ` Fabiano Rosas
2024-05-27 18:54     ` Steven Sistare via
2024-04-29 15:55 ` [PATCH V1 21/26] migration: migrate_add_blocker_mode Steve Sistare
2024-05-09 17:47   ` Fabiano Rosas
2024-04-29 15:55 ` [PATCH V1 22/26] migration: ram block cpr-exec blockers Steve Sistare
2024-05-09 18:01   ` Fabiano Rosas
2024-05-13 19:29     ` Steven Sistare
2024-04-29 15:55 ` [PATCH V1 23/26] migration: misc " Steve Sistare
2024-05-09 18:05   ` Fabiano Rosas
2024-05-24 12:40   ` Fabiano Rosas
2024-05-27 19:02     ` Steven Sistare via
2024-04-29 15:55 ` [PATCH V1 24/26] seccomp: cpr-exec blocker Steve Sistare
2024-05-09 18:16   ` Fabiano Rosas
2024-05-10  7:54   ` Daniel P. Berrangé
2024-05-13 19:29     ` Steven Sistare
2024-05-21  7:14       ` Daniel P. Berrangé
2024-04-29 15:55 ` [PATCH V1 25/26] migration: fix mismatched GPAs during cpr-exec Steve Sistare
2024-05-09 18:39   ` Fabiano Rosas
2024-04-29 15:55 ` [PATCH V1 26/26] migration: only-migratable-modes Steve Sistare
2024-05-09 19:14   ` Fabiano Rosas
2024-05-13 19:48     ` Steven Sistare [this message]
2024-05-13 21:57       ` Fabiano Rosas
2024-05-21  8:05   ` Daniel P. Berrangé
2024-05-02 16:13 ` cpr-exec doc (was Re: [PATCH V1 00/26] Live update: cpr-exec) Steven Sistare
2024-05-02 18:15   ` Peter Xu
2024-05-20 18:30 ` [PATCH V1 00/26] Live update: cpr-exec Steven Sistare
2024-05-20 22:28   ` Fabiano Rosas
2024-05-21  2:31     ` Peter Xu
2024-05-21 11:46       ` Steven Sistare
2024-05-27 17:45         ` Peter Xu
2024-05-28 15:10           ` Steven Sistare via
2024-05-28 16:42             ` Peter Xu
2024-05-30 17:17               ` Steven Sistare via
2024-05-30 19:23                 ` Peter Xu
2024-05-24 13:02 ` Fabiano Rosas
2024-05-24 14:07   ` Steven Sistare
2024-05-27 18:07 ` Peter Xu

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