Re: [Qemu-devel] [PATCH] Add a hint message to loadvm and exits on failure

[Juan Quintela <quintela@redhat.com>]

Jose Ricardo Ziviani <joserz@linux.ibm.com> wrote:
> This patch adds a small hint for the failure case of the load snapshot
> process. It may be useful for users to remember that the VM
> configuration has changed between the save and load processes.
>
> (qemu) loadvm vm-20180903083641
> Unknown savevm section or instance 'cpu_common' 4.
> Make sure that your current VM setup matches your saved VM setup, including any hotplugged devices
> Error -22 while loading VM state
> (qemu) device_add host-spapr-cpu-core,core-id=4
> (qemu) loadvm vm-20180903083641
> (qemu) c
> (qemu) info status
> VM status: running
>
> It also exits Qemu if the snapshot cannot be loaded before reaching the
> main loop (-loadvm in the command line).
>
> $ qemu-system-ppc64 ... -loadvm vm-20180903083641
> qemu-system-ppc64: Unknown savevm section or instance 'cpu_common' 4.
> Make sure that your current VM setup matches your saved VM setup, including any hotplugged devices
> qemu-system-ppc64: Error -22 while loading VM state
> $
>
> Signed-off-by: Jose Ricardo Ziviani <joserz@linux.ibm.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>

There are two bits of functionality on your patch, I will have put it as
two patches (yes, I know they are both trivial, but comment is bigger
than it should be).

Queued.


> ---
>  migration/savevm.c | 4 +++-
>  vl.c               | 1 +
>  2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 13e51f0e34..9692577318 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -2078,7 +2078,9 @@ qemu_loadvm_section_start_full(QEMUFile *f, MigrationIncomingState *mis)
>      /* Find savevm section */
>      se = find_se(idstr, instance_id);
>      if (se == NULL) {
> -        error_report("Unknown savevm section or instance '%s' %d",
> +        error_report("Unknown savevm section or instance '%s' %d. "
> +                     "Make sure that your current VM setup matches your "
> +                     "saved VM setup, including any hotplugged devices",
>                       idstr, instance_id);
>          return -EINVAL;
>      }
> diff --git a/vl.c b/vl.c
> index 5ba06adf78..c63270a76a 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -4620,6 +4620,7 @@ int main(int argc, char **argv, char **envp)
>          if (load_snapshot(loadvm, &local_err) < 0) {
>              error_report_err(local_err);
>              autostart = 0;
> +            exit(1);
>          }
>      }