Steve Sistare <steven.sist...@oracle.com> wrote:
> Add the cpr-reboot migration mode. Usage:
>
> $ qemu-system-$arch -monitor stdio ...
> QEMU 8.1.50 monitor - type 'help' for more information
> (qemu) migrate_set_capability x-ignore-shared on
> (qemu) migrate_set_parameter mode cpr-reboot
> (qemu) migrate -d file:vm.state
> (qemu) info status
> VM status: paused (postmigrate)
> (qemu) quit
>
> $ qemu-system-$arch -monitor stdio -incoming defer ...
> QEMU 8.1.50 monitor - type 'help' for more information
> (qemu) migrate_set_capability x-ignore-shared on
> (qemu) migrate_set_parameter mode cpr-reboot
> (qemu) migrate_incoming file:vm.state
> (qemu) info status
> VM status: running
>
> In this mode, the migrate command saves state to a file, allowing one
> to quit qemu, reboot to an updated kernel, and restart an updated version
> of qemu. The caller must specify a migration URI that writes to and reads
> from a file. Unlike normal mode, the use of certain local storage options
> does not block the migration, but the caller must not modify guest block
> devices between the quit and restart. The guest RAM memory-backend must
> be shared, and the @x-ignore-shared migration capability must be set,
> to avoid saving RAM to the file. Guest RAM must be non-volatile across
> reboot, such as by backing it with a dax device, but this is not enforced.
> The restarted qemu arguments must match those used to initially start qemu,
> plus the -incoming option.
Please, add this message to doc/<somewhere> instead (or additionally) to
the commit log.
> Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
> ---
> qapi/migration.json | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/qapi/migration.json b/qapi/migration.json
> index 184fb78..2d862fa 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -620,9 +620,23 @@
> #
> # @normal: the original form of migration. (since 8.2)
> #
> +# @cpr-reboot: The migrate command saves state to a file, allowing one to
> +# quit qemu, reboot to an updated kernel, and restart an updated
> +# version of qemu. The caller must specify a migration URI
> +# that writes to and reads from a file. Unlike normal mode,
> +# the use of certain local storage options does not block the
> +# migration, but the caller must not modify guest block devices
> +# between the quit and restart. The guest RAM memory-backend
> +# must be shared, and the @x-ignore-shared migration capability
> +# must be set, to avoid saving it to the file. Guest RAM must
> +# be non-volatile across reboot, such as by backing it with
> +# a dax device, but this is not enforced. The restarted qemu
> +# arguments must match those used to initially start qemu, plus
> +# the -incoming option. (since 8.2)
> +#
> ##
> { 'enum': 'MigMode',
> - 'data': [ 'normal' ] }
> + 'data': [ 'normal', 'cpr-reboot' ] }
>
> ##
> # @BitmapMigrationBitmapAliasTransform:
It only works with file backend, and we don't have any check for that.
Wondering how to add that check.
Additionally, you are not adding a migration test that does exactly what
you put there in the comment.
Thanks, Juan.
