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

[Daniel P. Berrangé]

On Thu, Jun 23, 2022 at 03:58:12PM +0200, Jiri Denemark wrote:
> Resolves: https://gitlab.com/libvirt/libvirt/-/issues/306
> 
> Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
> ---
>  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;
> +    }

It is also not compatible with compression, or TLS.


> 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",
>  );

Note the QEMU name was picked in case we later get zero copy
receive, as a separately enabled feature.


With regards,
Daniel
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