Re: [Qemu-devel] [PATCH 4/7] tpm-backend: Call interface methods only if backend implements them

[Marc-André Lureau]

Hi

On Fri, Mar 31, 2017 at 4:57 PM Amarnath Valluri <address@hidden>
wrote:

> This allows backend implementations left optional interface methods.
>
>
Does that make sense to make them optional? instead I would add asserts.

Signed-off-by: Amarnath Valluri <address@hidden>
> ---
>  backends/tpm.c           | 22 ++++++++++++++--------
>  hw/tpm/tpm_passthrough.c | 16 ----------------
>  2 files changed, 14 insertions(+), 24 deletions(-)
>
> diff --git a/backends/tpm.c b/backends/tpm.c
> index 00c82d7..0bdc5af 100644
> --- a/backends/tpm.c
> +++ b/backends/tpm.c
> @@ -50,14 +50,16 @@ const char *tpm_backend_get_desc(TPMBackend *s)
>  {
>      TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
>
> -    return k->ops->desc();
> +    return k->ops->desc ? k->ops->desc() : "";
>  }
>
>  void tpm_backend_destroy(TPMBackend *s)
>  {
>      TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
>
> -    k->ops->destroy(s);
> +    if (k->ops->destroy) {
> +        k->ops->destroy(s);
> +    }
>
>      object_unref(OBJECT(s));
>  }
> @@ -70,7 +72,7 @@ int tpm_backend_init(TPMBackend *s, TPMState *state,
>      s->tpm_state = state;
>      s->recv_data_callback = datacb;
>
> -    return k->ops->init(s);
> +    return k->ops->init ? k->ops->init(s) : 0;
>  }
>
>  int tpm_backend_startup_tpm(TPMBackend *s)
> @@ -87,21 +89,21 @@ int tpm_backend_startup_tpm(TPMBackend *s)
>                             NULL);
>      }
>
> -    return k->ops->startup_tpm(s);
> +    return k->ops->startup_tpm ? k->ops->startup_tpm(s) : 0;
>  }
>
>  bool tpm_backend_had_startup_error(TPMBackend *s)
>  {
>      TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
>
> -    return k->ops->had_startup_error(s);
> +    return k->ops->had_startup_error ? k->ops->had_startup_error(s) : 0;
>  }
>
>  size_t tpm_backend_realloc_buffer(TPMBackend *s, TPMSizedBuffer *sb)
>  {
>      TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
>
> -    return k->ops->realloc_buffer(sb);
> +    return k->ops->realloc_buffer ? k->ops->realloc_buffer(sb) :
> (size_t)0;
>  }
>
>  void tpm_backend_deliver_request(TPMBackend *s)
> @@ -114,7 +116,9 @@ void tpm_backend_reset(TPMBackend *s)
>  {
>      TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
>
> -    k->ops->reset(s);
> +    if (k->ops->reset) {
> +        k->ops->reset(s);
> +    }
>
>      tpm_backend_thread_end(s);
>  }
> @@ -123,7 +127,9 @@ void tpm_backend_cancel_cmd(TPMBackend *s)
>  {
>      TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
>
> -    k->ops->cancel_cmd(s);
> +    if (k->ops->cancel_cmd) {
> +        k->ops->cancel_cmd(s);
> +    }
>  }
>
>  bool tpm_backend_get_tpm_established_flag(TPMBackend *s)
> diff --git a/hw/tpm/tpm_passthrough.c b/hw/tpm/tpm_passthrough.c
> index cb63079..5b3bf1c 100644
> --- a/hw/tpm/tpm_passthrough.c
> +++ b/hw/tpm/tpm_passthrough.c
> @@ -228,15 +228,6 @@ static void tpm_passthrough_handle_request(TPMBackend
> *tb, TPMBackendCmd cmd)
>      }
>  }
>
> -/*
> - * Start the TPM (thread). If it had been started before, then terminate
> - * and start it again.
> - */
> -static int tpm_passthrough_startup_tpm(TPMBackend *tb)
> -{
> -    return 0;
> -}
> -
>  static void tpm_passthrough_reset(TPMBackend *tb)
>  {
>      TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
> @@ -248,11 +239,6 @@ static void tpm_passthrough_reset(TPMBackend *tb)
>      tpm_pt->had_startup_error = false;
>  }
>
> -static int tpm_passthrough_init(TPMBackend *tb)
> -{
> -    return 0;
> -}
> -
>

These two hunks could be squashed in earlier patch


>  static bool tpm_passthrough_get_tpm_established_flag(TPMBackend *tb)
>  {
>      return false;
> @@ -468,8 +454,6 @@ static const TPMDriverOps tpm_passthrough_driver = {
>      .desc                     = tpm_passthrough_create_desc,
>      .create                   = tpm_passthrough_create,
>      .destroy                  = tpm_passthrough_destroy,
> -    .init                     = tpm_passthrough_init,
> -    .startup_tpm              = tpm_passthrough_startup_tpm,
>      .realloc_buffer           = tpm_passthrough_realloc_buffer,
>      .reset                    = tpm_passthrough_reset,
>      .had_startup_error        = tpm_passthrough_get_startup_error,
> --
> 2.7.4
>
>
> --
Marc-André Lureau