Re: [PATCH v2 01/16] migration: Create migrate_rdma()

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, May 03, 2023 at 03:18:32PM +0200, Juan Quintela wrote:
> Helper to say if we are doing a migration over rdma.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> ---
>  migration/migration.h | 3 +++
>  migration/options.c   | 7 +++++++
>  migration/options.h   | 1 +
>  migration/rdma.c      | 4 +++-
>  4 files changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/migration/migration.h b/migration/migration.h
> index 3a918514e7..47fe116167 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -432,6 +432,9 @@ struct MigrationState {
>  
>      /* QEMU_VM_VMDESCRIPTION content filled for all non-iterable devices. */
>      JSONWriter *vmdesc;
> +
> +    /* Is this a rdma migration */
> +    bool rdma_migration;
>  };
>  
>  void migrate_set_state(int *state, int old_state, int new_state);
> diff --git a/migration/options.c b/migration/options.c
> index 53b7fc5d5d..39843f9325 100644
> --- a/migration/options.c
> +++ b/migration/options.c
> @@ -349,6 +349,13 @@ bool migrate_postcopy(void)
>      return migrate_postcopy_ram() || migrate_dirty_bitmaps();
>  }
>  
> +bool migrate_rdma(void)
> +{
> +    MigrationState *s = migrate_get_current();
> +
> +    return s->rdma_migration;
> +}
> +
>  bool migrate_tls(void)
>  {
>      MigrationState *s = migrate_get_current();
> diff --git a/migration/options.h b/migration/options.h
> index 3c322867cd..3c555e28c7 100644
> --- a/migration/options.h
> +++ b/migration/options.h
> @@ -61,6 +61,7 @@ bool migrate_zero_copy_send(void);
>  
>  bool migrate_multifd_flush_after_each_section(void);
>  bool migrate_postcopy(void);
> +bool migrate_rdma(void);
>  bool migrate_tls(void);
>  
>  /* capabilities helpers */
> diff --git a/migration/rdma.c b/migration/rdma.c
> index 7e747b2595..b026e98519 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -4119,6 +4119,7 @@ void rdma_start_incoming_migration(const char *host_port, Error **errp)
>      int ret;
>      RDMAContext *rdma;
>      Error *local_err = NULL;
> +    MigrationState *s = migrate_get_current();
>  
>      trace_rdma_start_incoming_migration();
>  
> @@ -4149,7 +4150,7 @@ void rdma_start_incoming_migration(const char *host_port, Error **errp)
>      }
>  
>      trace_rdma_start_incoming_migration_after_rdma_listen();
> -
> +    s->rdma_migration = true;
>      qemu_set_fd_handler(rdma->channel->fd, rdma_accept_incoming_migration,
>                          NULL, (void *)(intptr_t)rdma);
>      return;
> @@ -4225,6 +4226,7 @@ void rdma_start_outgoing_migration(void *opaque,
>  
>      trace_rdma_start_outgoing_migration_after_rdma_connect();
>  
> +    s->rdma_migration = true;
>      s->to_dst_file = qemu_fopen_rdma(rdma, "wb");
>      migrate_fd_connect(s, NULL);
>      return;

Is the "MigrationState" allocated freshly for every incoming
or outgoing migration ?  If it is reused, then something
needs to set 's->rdma_migration = false' in non-RDMA code
paths.

With regards,
Daniel
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