[libvirt PATCH 7/7] qemu_migration: Implement VIR_MIGRATE_ZEROCOPY flag

Resolves: https://gitlab.com/libvirt/libvirt/-/issues/306 Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com&gt; --- src/qemu/qemu_migration.c | 21 +++++++++++++++++++++ src/qemu/qemu_migration.h | 1 + src/qemu/qemu_migration_params.c | 6 ++++++ src/qemu/qemu_migration_params.h | 1 + 4 files changed, 29 insertions(+) diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c index 272f1b1b59..02a465f6cb 100644 --- a/src/qemu/qemu_migration.c +++ b/src/qemu/qemu_migration.c @@ -2634,6 +2634,12 @@ qemuMigrationSrcBeginPhase(virQEMUDriver *driver, } } + if (flags & VIR_MIGRATE_ZEROCOPY && !(flags & VIR_MIGRATE_PARALLEL)) { + virReportError(VIR_ERR_OPERATION_INVALID, "%s", + _("zero-copy is only available for parallel migration")); + return NULL; + } + if (flags & (VIR_MIGRATE_NON_SHARED_DISK | VIR_MIGRATE_NON_SHARED_INC)) { if (flags & VIR_MIGRATE_NON_SHARED_SYNCHRONOUS_WRITES && !virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV)) { @@ -4798,6 +4804,21 @@ qemuMigrationSrcRun(virQEMUDriver *driver, migParams) < 0) goto error; + if (flags & VIR_MIGRATE_ZEROCOPY) { + /* Zero-copy requires pages in transfer to be locked in host memory. + * Unfortunately, we have no reliable way of computing how many pages + * will need to be locked at the same time. Thus we set the limit to + * the whole guest memory and reset it back once migration is done. */ + unsigned long long limit; + + if (virMemoryLimitIsSet(vm->def->mem.hard_limit)) + limit = vm->def->mem.hard_limit; + else + limit = virDomainDefGetMemoryTotal(vm->def); + + if (qemuDomainSetMaxMemLock(vm, limit << 10, &priv->preMigrationMemlock) < 0) + goto error; + } if (storageMigration) { if (mig->nbd) { diff --git a/src/qemu/qemu_migration.h b/src/qemu/qemu_migration.h index fbc0549b34..81cc1e91c0 100644 --- a/src/qemu/qemu_migration.h +++ b/src/qemu/qemu_migration.h @@ -61,6 +61,7 @@ VIR_MIGRATE_PARALLEL | \ VIR_MIGRATE_NON_SHARED_SYNCHRONOUS_WRITES | \ VIR_MIGRATE_POSTCOPY_RESUME | \ + VIR_MIGRATE_ZEROCOPY | \ 0) /* All supported migration parameters and their types. */ diff --git a/src/qemu/qemu_migration_params.c b/src/qemu/qemu_migration_params.c index 4e83d8d8bd..cc66ed8229 100644 --- a/src/qemu/qemu_migration_params.c +++ b/src/qemu/qemu_migration_params.c @@ -94,6 +94,7 @@ VIR_ENUM_IMPL(qemuMigrationCapability, "multifd", "dirty-bitmaps", "return-path", + "zero-copy-send", ); @@ -175,6 +176,11 @@ static const qemuMigrationParamsFlagMapItem qemuMigrationParamsFlagMap[] = { VIR_MIGRATE_TUNNELLED, QEMU_MIGRATION_CAP_RETURN_PATH, QEMU_MIGRATION_SOURCE | QEMU_MIGRATION_DESTINATION}, + + {QEMU_MIGRATION_FLAG_REQUIRED, + VIR_MIGRATE_ZEROCOPY, + QEMU_MIGRATION_CAP_ZERO_COPY_SEND, + QEMU_MIGRATION_SOURCE}, }; /* Translation from VIR_MIGRATE_PARAM_* typed parameters to diff --git a/src/qemu/qemu_migration_params.h b/src/qemu/qemu_migration_params.h index f2f0090343..d1184acded 100644 --- a/src/qemu/qemu_migration_params.h +++ b/src/qemu/qemu_migration_params.h @@ -39,6 +39,7 @@ typedef enum { QEMU_MIGRATION_CAP_MULTIFD, QEMU_MIGRATION_CAP_BLOCK_DIRTY_BITMAPS, QEMU_MIGRATION_CAP_RETURN_PATH, + QEMU_MIGRATION_CAP_ZERO_COPY_SEND, QEMU_MIGRATION_CAP_LAST } qemuMigrationCapability; -- 2.35.1