Re: [PATCH-for-5.1 1/2] tpm: Display when no backend is available

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

On 7/22/20 7:23 AM, Philippe Mathieu-Daudé wrote:
> Display "No TPM backend available in this binary." error when
> no backend is available.
>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>   tpm.c | 21 +++++++++++++++++++++
>   1 file changed, 21 insertions(+)
>
> diff --git a/tpm.c b/tpm.c
> index fe03b24858..e36803a64d 100644
> --- a/tpm.c
> +++ b/tpm.c
> @@ -41,6 +41,22 @@ tpm_be_find_by_type(enum TpmType type)
>       return TPM_BACKEND_CLASS(oc);
>   }
>   
> +/*
> + * Walk the list of available TPM backend drivers and count them.
> + */
> +static int tpm_backend_drivers_count(void)
> +{
> +    int count = 0, i;
> +
> +    for (i = 0; i < TPM_TYPE__MAX; i++) {
> +        const TPMBackendClass *bc = tpm_be_find_by_type(i);
> +        if (bc) {
> +            count++;
> +        }
> +    }
> +    return count;
> +}
> +
>   /*
>    * Walk the list of available TPM backend drivers and display them on the
>    * screen.
> @@ -87,6 +103,11 @@ static int tpm_init_tpmdev(void *dummy, QemuOpts *opts, Error **errp)
>       TPMBackend *drv;
>       int i;
>   
> +    if (!tpm_backend_drivers_count()) {
> +        error_setg(errp, "No TPM backend available in this binary.");
> +        return 1;
> +    }
> +
>       if (!QLIST_EMPTY(&tpm_backends)) {
>           error_setg(errp, "Only one TPM is allowed.");
>           return 1;


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