diff --git a/migration/migration.c b/migration/migration.c index 1986cb8573..2262f348af 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -58,6 +58,7 @@ #include "qemu/queue.h" #include "multifd.h" #include "qemu/yank.h" +#include "sysemu/cpus.h" #ifdef CONFIG_VFIO #include "hw/vfio/vfio-common.h" @@ -134,6 +135,38 @@ enum mig_rp_message_type { MIG_RP_MSG_MAX }; +/* Migration capabilities set */ +struct MigrateCapsSet { + int size; /* Capability set size */ + MigrationCapability caps[]; /* Variadic array of capabilities */ +}; +typedef struct MigrateCapsSet MigrateCapsSet; + +/* Define and initialize MigrateCapsSet */ +#define INITIALIZE_MIGRATE_CAPS_SET(_name, ...) \ + MigrateCapsSet _name = { \ + .size = sizeof((int []) { __VA_ARGS__ }) / sizeof(int), \ + .caps = { __VA_ARGS__ } \ + } + +/* Background-snapshot compatibility check list */ +static const +INITIALIZE_MIGRATE_CAPS_SET(check_caps_background_snapshot, + MIGRATION_CAPABILITY_POSTCOPY_RAM, + MIGRATION_CAPABILITY_DIRTY_BITMAPS, + MIGRATION_CAPABILITY_POSTCOPY_BLOCKTIME, + MIGRATION_CAPABILITY_LATE_BLOCK_ACTIVATE, + MIGRATION_CAPABILITY_RETURN_PATH, + MIGRATION_CAPABILITY_MULTIFD, + MIGRATION_CAPABILITY_PAUSE_BEFORE_SWITCHOVER, + MIGRATION_CAPABILITY_AUTO_CONVERGE, + MIGRATION_CAPABILITY_RELEASE_RAM, + MIGRATION_CAPABILITY_RDMA_PIN_ALL, + MIGRATION_CAPABILITY_COMPRESS, + MIGRATION_CAPABILITY_XBZRLE, + MIGRATION_CAPABILITY_X_COLO, + MIGRATION_CAPABILITY_VALIDATE_UUID); + /* When we add fault tolerance, we could have several migrations at once. For now we don't need to add dynamic creation of migration */ @@ -1089,6 +1122,31 @@ static void fill_source_migration_info(MigrationInfo *info) info->status = s->state; } +typedef enum WriteTrackingSupport { + WT_SUPPORT_UNKNOWN = 0, + WT_SUPPORT_ABSENT, + WT_SUPPORT_AVAILABLE, + WT_SUPPORT_COMPATIBLE +} WriteTrackingSupport; + +static +WriteTrackingSupport migrate_query_write_tracking(void) +{ + /* Check if kernel supports required UFFD features */ + if (!ram_write_tracking_available()) { + return WT_SUPPORT_ABSENT; + } + /* + * Check if current memory configuration is + * compatible with required UFFD features. + */ + if (!ram_write_tracking_compatible()) { + return WT_SUPPORT_AVAILABLE; + } + + return WT_SUPPORT_COMPATIBLE; +} + /** * @migration_caps_check - check capability validity * @@ -1150,6 +1208,39 @@ static bool migrate_caps_check(bool *cap_list, } } + if (cap_list[MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT]) { + WriteTrackingSupport wt_support; + int idx; + /* + * Check if 'background-snapshot' capability is supported by + * host kernel and compatible with guest memory configuration. + */ + wt_support = migrate_query_write_tracking(); + if (wt_support < WT_SUPPORT_AVAILABLE) { + error_setg(errp, "Background-snapshot is not supported by host kernel"); + return false; + } + if (wt_support < WT_SUPPORT_COMPATIBLE) { + error_setg(errp, "Background-snapshot is not compatible " + "with guest memory configuration"); + return false; + } + + /* + * Check if there are any migration capabilities + * incompatible with 'background-snapshot'. + */ + for (idx = 0; idx < check_caps_background_snapshot.size; idx++) { + int incomp_cap = check_caps_background_snapshot.caps[idx]; + if (cap_list[incomp_cap]) { + error_setg(errp, + "Background-snapshot is not compatible with %s", + MigrationCapability_str(incomp_cap)); + return false; + } + } + } + return true; } @@ -2491,6 +2582,15 @@ bool migrate_use_block_incremental(void) return s->parameters.block_incremental; } +bool migrate_background_snapshot(void) +{ + MigrationState *s; + + s = migrate_get_current(); + + return s->enabled_capabilities[MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT]; +} + /* migration thread support */ /* * Something bad happened to the RP stream, mark an error @@ -3784,6 +3884,8 @@ static Property migration_properties[] = { DEFINE_PROP_MIG_CAP("x-block", MIGRATION_CAPABILITY_BLOCK), DEFINE_PROP_MIG_CAP("x-return-path", MIGRATION_CAPABILITY_RETURN_PATH), DEFINE_PROP_MIG_CAP("x-multifd", MIGRATION_CAPABILITY_MULTIFD), + DEFINE_PROP_MIG_CAP("x-background-snapshot", + MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT), DEFINE_PROP_END_OF_LIST(), }; diff --git a/migration/migration.h b/migration/migration.h index d096b77f74..f40338cfbf 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -341,6 +341,7 @@ int migrate_compress_wait_thread(void); int migrate_decompress_threads(void); bool migrate_use_events(void); bool migrate_postcopy_blocktime(void); +bool migrate_background_snapshot(void); /* Sending on the return path - generic and then for each message type */ void migrate_send_rp_shut(MigrationIncomingState *mis, diff --git a/migration/ram.c b/migration/ram.c index 7811cde643..ae8de17153 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -3788,6 +3788,27 @@ static int ram_resume_prepare(MigrationState *s, void *opaque) return 0; } +/* ram_write_tracking_available: check if kernel supports required UFFD features + * + * Returns true if supports, false otherwise + */ +bool ram_write_tracking_available(void) +{ + /* TODO: implement */ + return false; +} + +/* ram_write_tracking_compatible: check if guest configuration is + * compatible with 'write-tracking' + * + * Returns true if compatible, false otherwise + */ +bool ram_write_tracking_compatible(void) +{ + /* TODO: implement */ + return false; +} + static SaveVMHandlers savevm_ram_handlers = { .save_setup = ram_save_setup, .save_live_iterate = ram_save_iterate, diff --git a/migration/ram.h b/migration/ram.h index 011e85414e..1a9ff90304 100644 --- a/migration/ram.h +++ b/migration/ram.h @@ -79,4 +79,8 @@ void colo_flush_ram_cache(void); void colo_release_ram_cache(void); void colo_incoming_start_dirty_log(void); +/* Background snapshot */ +bool ram_write_tracking_available(void); +bool ram_write_tracking_compatible(void); + #endif diff --git a/qapi/migration.json b/qapi/migration.json index d1d9632c2a..6c12b368aa 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -442,6 +442,11 @@ # @validate-uuid: Send the UUID of the source to allow the destination # to ensure it is the same. (since 4.2) # +# @background-snapshot: If enabled, the migration stream will be a snapshot +# of the VM exactly at the point when the migration +# procedure starts. The VM RAM is saved with running VM. +# (since 6.0) +# # Since: 1.2 ## { 'enum': 'MigrationCapability', @@ -449,7 +454,7 @@ 'compress', 'events', 'postcopy-ram', 'x-colo', 'release-ram', 'block', 'return-path', 'pause-before-switchover', 'multifd', 'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate', - 'x-ignore-shared', 'validate-uuid' ] } + 'x-ignore-shared', 'validate-uuid', 'background-snapshot'] } ## # @MigrationCapabilityStatus: