Re: [Qemu-devel] [PATCH 2/2] tpm_tis: Return 0 for every register in case of failure mode

[Marc-André Lureau]

Hi Stefan

On Sat, Nov 11, 2017 at 4:39 AM, Stefan Berger
<address@hidden> wrote:
> Rather than returning ~0, return 0 for every register in case of
> failure mode. The '0' is better to indicate that there's no device
> there.
>
> Signed-off-by: Stefan Berger <address@hidden>
> ---
>  hw/tpm/tpm_tis.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/tpm/tpm_tis.c b/hw/tpm/tpm_tis.c
> index eca3374..d0bdd96 100644
> --- a/hw/tpm/tpm_tis.c
> +++ b/hw/tpm/tpm_tis.c
> @@ -519,7 +519,7 @@ static uint64_t tpm_tis_mmio_read(void *opaque, hwaddr 
> addr,
>      uint8_t v;
>
>      if (tpm_backend_had_startup_error(s->be_driver)) {
> -        return val;
> +        return 0;
>      }

it's not obvious to me why it's better. Could you detail a bit more the reason?

why not change the initialization of val instead?

>
>      switch (offset) {
> --
> 2.5.5
>
>



-- 
Marc-André Lureau