Re: [PATCH RFC 18/21] migration: Allow postcopy_register_shared_ufd() to fail

[Juan Quintela]

Peter Xu <peterx@redhat.com> wrote:
> Let's fail double-map for vhost-user and any potential users that can have
> a remote userfaultfd for now.
>
> Signed-off-by: Peter Xu <peterx@redhat.com>

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

But

> -void postcopy_register_shared_ufd(struct PostCopyFD *pcfd)
> +int postcopy_register_shared_ufd(struct PostCopyFD *pcfd)
>  {
>      MigrationIncomingState *mis = migration_incoming_get_current();
>  
> +    if (migrate_hugetlb_doublemap()) {
> +        return -EINVAL;

I am not sure that -EINVAL is the best answer here.
There is not a problem with the value.  The problem is that both
features together don't work.

As an alternative:

ENOSYS 38 Function not implemented

But I am not sure that this is much better :-(

Later, Juan.