Re: [PATCH V1 14/32] savevm: VMS_RESTART and cprsave restart

[Dr. David Alan Gilbert]

* Steve Sistare (steven.sistare@oracle.com) wrote:
> Add the VMS_RESTART variant of vmstate, for use when upgrading qemu in place
> on the same host without a reboot.  Invoke it using:
>   cprsave <filename> restart
> 
> VMS_RESTART supports guest ram mapped by private anonymous memory, versus
> VMS_REBOOT which requires that guest ram be mapped by persistent shared
> memory.  Subsequent patches complete its implementation.
> 
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>

You should find with the enum like Eric suggests this mostly disappears;
but also you might want to put it after the patches that implement it.

Dave

> ---
>  hmp-commands.hx             | 4 +++-
>  include/migration/vmstate.h | 1 +
>  migration/savevm.c          | 4 +++-
>  monitor/qmp-cmds.c          | 2 +-
>  qapi/migration.json         | 1 +
>  5 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 7517876..11a2089 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -369,7 +369,7 @@ ERST
>      {
>          .name       = "cprsave",
>          .args_type  = "file:s,mode:s",
> -        .params     = "file 'reboot'",
> +        .params     = "file 'restart'|'reboot'",
>          .help       = "create a checkpoint of the VM in file",
>          .cmd        = hmp_cprsave,
>      },
> @@ -380,6 +380,8 @@ SRST
>    in *file*.
>    If *mode* is 'reboot', the checkpoint can be cprload'ed after a host kexec
>    reboot.
> +  If *mode* is 'restart', the checkpoint can be cprload'ed after restarting
> +  qemu.
>    exec() /usr/bin/qemu-exec if it exists, else exec 
> /usr/bin/qemu-system-x86_64,
>    passing all the original command line arguments.  The VCPUs remain paused.
>  ERST
> diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
> index c58551a..8239b84 100644
> --- a/include/migration/vmstate.h
> +++ b/include/migration/vmstate.h
> @@ -162,6 +162,7 @@ typedef enum {
>      VMS_MIGRATE  = (1U << 1),
>      VMS_SNAPSHOT = (1U << 2),
>      VMS_REBOOT   = (1U << 3),
> +    VMS_RESTART  = (1U << 4),
>      VMS_MODE_ALL = ~0U
>  } VMStateMode;
>  
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 00f493b..38cc63a 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -2708,6 +2708,8 @@ void save_cpr_snapshot(const char *file, const char 
> *mode, Error **errp)
>  
>      if (!strcmp(mode, "reboot")) {
>          op = VMS_REBOOT;
> +    } else if (!strcmp(mode, "restart")) {
> +        op = VMS_RESTART;
>      } else {
>          error_setg(errp, "cprsave: bad mode %s", mode);
>          return;
> @@ -2973,7 +2975,7 @@ void load_cpr_snapshot(const char *file, Error **errp)
>          return;
>      }
>  
> -    ret = qemu_loadvm_state(f, VMS_REBOOT);
> +    ret = qemu_loadvm_state(f, VMS_REBOOT | VMS_RESTART);
>      qemu_fclose(f);
>      if (ret < 0) {
>          error_setg(errp, "Error %d while loading VM state", ret);
> diff --git a/monitor/qmp-cmds.c b/monitor/qmp-cmds.c
> index 8c400e6..8a74c6e 100644
> --- a/monitor/qmp-cmds.c
> +++ b/monitor/qmp-cmds.c
> @@ -164,7 +164,7 @@ void qmp_cont(Error **errp)
>  
>  char *qmp_cprinfo(Error **errp)
>  {
> -    return g_strdup("reboot");
> +    return g_strdup("reboot restart");
>  }
>  
>  void qmp_cprsave(const char *file, const char *mode, Error **errp)
> diff --git a/qapi/migration.json b/qapi/migration.json
> index 8190b16..d22992b 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -1639,6 +1639,7 @@
>  #
>  # @file: name of checkpoint file
>  # @mode: 'reboot' : checkpoint can be cprload'ed after a host kexec reboot.
> +#        'restart': checkpoint can be cprload'ed after restarting qemu.
>  #
>  # Since 5.0
>  ##
> -- 
> 1.8.3.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK