Re: [PATCH 2/3] m25p80: Improve command handling for Jedec and unsupported commands

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Hi Guenter,

On 2/3/20 7:09 PM, Guenter Roeck wrote:
> Always report 6 bytes of JEDEC data. Fill remaining data with 0.
> 
> For unsupported commands, keep sending a value of 0 until the chip
> is deselected.

Two changes, I'd rather see 2 patches. If you happen to respin they are 
welcome. As the split is trivial maybe a block maintainer is OK to do 
it. Regardless the outcome:
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> 
> Both changes avoid attempts to decode random commands. Up to now this
> happened if the reported Jedec data was shorter than 6 bytes but the
> host read 6 bytes, and with all unsupported commands.
> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
>   hw/block/m25p80.c | 10 +++++++++-
>   1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c
> index 63e050d7d3..aca75edcc1 100644
> --- a/hw/block/m25p80.c
> +++ b/hw/block/m25p80.c
> @@ -1040,8 +1040,11 @@ static void decode_new_cmd(Flash *s, uint32_t value)
>           for (i = 0; i < s->pi->id_len; i++) {
>               s->data[i] = s->pi->id[i];
>           }
> +        for (; i < SPI_NOR_MAX_ID_LEN; i++) {
> +            s->data[i] = 0;
> +        }
>   
> -        s->len = s->pi->id_len;
> +        s->len = SPI_NOR_MAX_ID_LEN;
>           s->pos = 0;
>           s->state = STATE_READING_DATA;
>           break;
> @@ -1158,6 +1161,11 @@ static void decode_new_cmd(Flash *s, uint32_t value)
>           s->quad_enable = false;
>           break;
>       default:
> +        s->pos = 0;
> +        s->len = 1;
> +        s->state = STATE_READING_DATA;
> +        s->data_read_loop = true;
> +        s->data[0] = 0;
>           qemu_log_mask(LOG_GUEST_ERROR, "M25P80: Unknown cmd %x\n", value);
>           break;
>       }
>