Re: [Qemu-devel] [PATCH v2 4/9] tpm-backend: Made few interface methods optional

[Stefan Berger <stefanb@linux.vnet.ibm.com>]

On 04/07/2017 10:30 AM, Amarnath Valluri wrote:
> This allows backend implementations left optional interface methods.
> For mandatory methods assertion checks added.
>
> Signed-off-by: Amarnath Valluri <amarnath.valluri@intel.com>
> ---
>   backends/tpm.c           | 28 +++++++++++++++++++++-------
>   hw/tpm/tpm_passthrough.c | 16 ----------------
>   2 files changed, 21 insertions(+), 23 deletions(-)
>
> diff --git a/backends/tpm.c b/backends/tpm.c
> index 99d2b2b..c2be17b 100644
> --- a/backends/tpm.c
> +++ b/backends/tpm.c
> @@ -48,14 +48,16 @@ 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));
>   }
> @@ -68,7 +70,7 @@ 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)
> @@ -82,13 +84,15 @@ int tpm_backend_startup_tpm(TPMBackend *s)
>                                          NULL);
>       g_thread_pool_push(s->thread_pool, (gpointer)TPM_BACKEND_CMD_INIT, 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);
>
> +    assert(k->ops->had_startup_error);
> +
>       return k->ops->had_startup_error(s);
>   }
>
> @@ -96,6 +100,8 @@ size_t tpm_backend_realloc_buffer(TPMBackend *s, TPMSizedBuffer *sb)
>   {
>       TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
>
> +    assert(k->ops->realloc_buffer);
> +
>       return k->ops->realloc_buffer(sb);
>   }
>
> @@ -109,7 +115,9 @@ 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);
>   }
> @@ -118,6 +126,8 @@ void tpm_backend_cancel_cmd(TPMBackend *s)
>   {
>       TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
>
> +    g_assert(k->ops->cancel_cmd);
> +
>       k->ops->cancel_cmd(s);
>   }
>
> @@ -125,20 +135,24 @@ bool tpm_backend_get_tpm_established_flag(TPMBackend *s)
>   {
>       TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
>
> -    return k->ops->get_tpm_established_flag(s);
> +    return k->ops->get_tpm_established_flag ?
> +           k->ops->get_tpm_established_flag(s) : false;
>   }
>
>   int tpm_backend_reset_tpm_established_flag(TPMBackend *s, uint8_t locty)
>   {
>       TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
>
> -    return k->ops->reset_tpm_established_flag(s, locty);
> +    return k->ops->reset_tpm_established_flag ?
> +           k->ops->reset_tpm_established_flag(s, locty) : 0;
>   }
>
>   TPMVersion tpm_backend_get_tpm_version(TPMBackend *s)
>   {
>       TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
>
> +    assert(k->ops->get_tpm_version);
> +
>       return k->ops->get_tpm_version(s);
>   }
>
> diff --git a/hw/tpm/tpm_passthrough.c b/hw/tpm/tpm_passthrough.c
> index 65831b5..0f543bd 100644
> --- a/hw/tpm/tpm_passthrough.c
> +++ b/hw/tpm/tpm_passthrough.c
> @@ -227,15 +227,6 @@ 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);
> @@ -247,11 +238,6 @@ static void tpm_passthrough_reset(TPMBackend *tb)
>       tpm_pt->had_startup_error = false;
>   }
>
> -static int tpm_passthrough_init(TPMBackend *tb)
> -{
> -    return 0;
> -}
> -
>   static bool tpm_passthrough_get_tpm_established_flag(TPMBackend *tb)
>   {
>       return false;
> @@ -467,8 +453,6 @@ 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,


Reviewed-by: Stefan Berger <stefanb@linux.vnet.ibm.com>