To migrate virtio-net TAP device backend (including open fds) locally, user should simply set migration parameter
backend-transfer = ["virtio-net-tap"] Why not simple boolean? To simplify migration to further versions, when more devices will support backend-transfer migration. Alternatively, we may add per-device option to disable backend-transfer migration, but still: 1. It's more comfortable to set same capabilities/parameters on both source and target QEMU, than care about each device. 2. To not break the design, that machine-type + device options + migration capabilities and parameters are fully define the resulting migration stream. We'll break this if add in future more backend-transfer support in devices under same backend-transfer=true parameter. The commit only brings the interface, the realization will come in later commit. That's why we add a temporary not-implemented error in migrate_params_check(). Signed-off-by: Vladimir Sementsov-Ogievskiy <[email protected]> --- migration/options.c | 39 +++++++++++++++++++++++++++++++++++++++ migration/options.h | 2 ++ qapi/migration.json | 42 ++++++++++++++++++++++++++++++++++++------ 3 files changed, 77 insertions(+), 6 deletions(-) diff --git a/migration/options.c b/migration/options.c index 5183112775..76709af3ab 100644 --- a/migration/options.c +++ b/migration/options.c @@ -13,6 +13,7 @@ #include "qemu/osdep.h" #include "qemu/error-report.h" +#include "qapi/util.h" #include "exec/target_page.h" #include "qapi/clone-visitor.h" #include "qapi/error.h" @@ -262,6 +263,20 @@ bool migrate_mapped_ram(void) return s->capabilities[MIGRATION_CAPABILITY_MAPPED_RAM]; } +bool migrate_virtio_net_tap(void) +{ + MigrationState *s = migrate_get_current(); + BackendTransferList *el = s->parameters.backend_transfer; + + for ( ; el; el = el->next) { + if (el->value == BACKEND_TRANSFER_VIRTIO_NET_TAP) { + return true; + } + } + + return false; +} + bool migrate_ignore_shared(void) { MigrationState *s = migrate_get_current(); @@ -963,6 +978,12 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp) params->cpr_exec_command = QAPI_CLONE(strList, s->parameters.cpr_exec_command); + if (s->parameters.backend_transfer) { + params->has_backend_transfer = true; + params->backend_transfer = QAPI_CLONE(BackendTransferList, + s->parameters.backend_transfer); + } + return params; } @@ -997,6 +1018,7 @@ void migrate_params_init(MigrationParameters *params) params->has_zero_page_detection = true; params->has_direct_io = true; params->has_cpr_exec_command = true; + params->has_backend_transfer = true; } /* @@ -1183,6 +1205,12 @@ bool migrate_params_check(MigrationParameters *params, Error **errp) return false; } + /* TODO: implement backend-transfer and remove this check */ + if (params->has_backend_transfer) { + error_setg(errp, "Not implemented"); + return false; + } + return true; } @@ -1305,6 +1333,10 @@ static void migrate_params_test_apply(MigrateSetParameters *params, if (params->has_cpr_exec_command) { dest->cpr_exec_command = params->cpr_exec_command; } + + if (params->has_backend_transfer) { + dest->backend_transfer = params->backend_transfer; + } } static void migrate_params_apply(MigrateSetParameters *params, Error **errp) @@ -1443,6 +1475,13 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp) s->parameters.cpr_exec_command = QAPI_CLONE(strList, params->cpr_exec_command); } + + if (params->has_backend_transfer) { + qapi_free_BackendTransferList(s->parameters.backend_transfer); + + s->parameters.backend_transfer = QAPI_CLONE(BackendTransferList, + params->backend_transfer); + } } void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp) diff --git a/migration/options.h b/migration/options.h index 82d839709e..55c0345433 100644 --- a/migration/options.h +++ b/migration/options.h @@ -87,6 +87,8 @@ const char *migrate_tls_hostname(void); uint64_t migrate_xbzrle_cache_size(void); ZeroPageDetection migrate_zero_page_detection(void); +bool migrate_virtio_net_tap(void); + /* parameters helpers */ bool migrate_params_check(MigrationParameters *params, Error **errp); diff --git a/qapi/migration.json b/qapi/migration.json index be0f3fcc12..1bfe7df191 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -770,6 +770,19 @@ '*transform': 'BitmapMigrationBitmapAliasTransform' } } +## +# @BackendTransfer: +# +# @virtio-net-tap: Enable backend-transfer migration for +# virtio-net/tap. When enabled, TAP fds and all related state are +# passed to the destination in the migration channel (which must +# be a UNIX domain socket). +# +# Since: 10.2 +## +{ 'enum': 'BackendTransfer', + 'data': [ 'virtio-net-tap' ] } + ## # @BitmapMigrationNodeAlias: # @@ -951,9 +964,13 @@ # is @cpr-exec. The first list element is the program's filename, # the remainder its arguments. (Since 10.2) # +# @backend-transfer: List of targets for backend-transfer migration. +# See description in `BackendTransfer`. Default is no +# backend-transfer migration (Since 10.2) +# # Features: # -# @unstable: Members @x-checkpoint-delay and +# @unstable: Members @backend-transfer, @x-checkpoint-delay and # @x-vcpu-dirty-limit-period are experimental. # # Since: 2.4 @@ -978,7 +995,8 @@ 'mode', 'zero-page-detection', 'direct-io', - 'cpr-exec-command'] } + 'cpr-exec-command', + { 'name': 'backend-transfer', 'features': ['unstable'] } ] } ## # @MigrateSetParameters: @@ -1137,9 +1155,13 @@ # is @cpr-exec. The first list element is the program's filename, # the remainder its arguments. (Since 10.2) # +# @backend-transfer: List of targets for backend-transfer migration. +# See description in `BackendTransfer`. Default is no +# backend-transfer migration (Since 10.2) +# # Features: # -# @unstable: Members @x-checkpoint-delay and +# @unstable: Members @backend-transfer, @x-checkpoint-delay and # @x-vcpu-dirty-limit-period are experimental. # # TODO: either fuse back into `MigrationParameters`, or make @@ -1179,7 +1201,9 @@ '*mode': 'MigMode', '*zero-page-detection': 'ZeroPageDetection', '*direct-io': 'bool', - '*cpr-exec-command': [ 'str' ]} } + '*cpr-exec-command': [ 'str' ], + '*backend-transfer': { 'type': [ 'BackendTransfer' ], + 'features': [ 'unstable' ] } } } ## # @migrate-set-parameters: @@ -1352,9 +1376,13 @@ # is @cpr-exec. The first list element is the program's filename, # the remainder its arguments. (Since 10.2) # +# @backend-transfer: List of targets for backend-transfer migration. +# See description in `BackendTransfer`. Default is no +# backend-transfer migration (Since 10.2) +# # Features: # -# @unstable: Members @x-checkpoint-delay and +# @unstable: Members @backend-transfer, @x-checkpoint-delay and # @x-vcpu-dirty-limit-period are experimental. # # Since: 2.4 @@ -1391,7 +1419,9 @@ '*mode': 'MigMode', '*zero-page-detection': 'ZeroPageDetection', '*direct-io': 'bool', - '*cpr-exec-command': [ 'str' ]} } + '*cpr-exec-command': [ 'str' ], + '*backend-transfer': { 'type': [ 'BackendTransfer' ], + 'features': [ 'unstable' ] } } } ## # @query-migrate-parameters: -- 2.48.1
