Re: [Qemu-devel] [PATCH 06/20] sdcard: Add a "validate-crc" property

[Alistair Francis]

On Fri, May 4, 2018 at 9:00 AM Philippe Mathieu-Daudé <address@hidden>
wrote:

> Since not all modelled controllers use the CRC verification (which is
> somehow expensive), let the controller have a configurable property
> to enable verification.

> So far only the Milkymist controller uses it.

> This silent the Coverity warning:

>    "Code block is unreachable because of the syntactic structure of the
code (CWE-561)"

> and fixes the following issue:

> - CID1005332 (hw/sd/sd.c::sd_req_crc_validate) Structurally dead code

> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>

Reviewed-by: Alistair Francis <address@hidden>

Alistair

> ---
>   hw/sd/milkymist-memcard.c |  1 +
>   hw/sd/sd.c                | 12 ++++++++----
>   2 files changed, 9 insertions(+), 4 deletions(-)

> diff --git a/hw/sd/milkymist-memcard.c b/hw/sd/milkymist-memcard.c
> index d8cbb7b681..04babc092f 100644
> --- a/hw/sd/milkymist-memcard.c
> +++ b/hw/sd/milkymist-memcard.c
> @@ -278,6 +278,7 @@ static void milkymist_memcard_realize(DeviceState
*dev, Error **errp)
>       blk = dinfo ? blk_by_legacy_dinfo(dinfo) : NULL;
>       carddev = qdev_create(&s->sdbus.qbus, TYPE_SD_CARD);
>       qdev_prop_set_drive(carddev, "drive", blk, &err);
> +    object_property_set_bool(OBJECT(carddev), true, "validate-crc",
&err);
>       object_property_set_bool(OBJECT(carddev), true, "realized", &err);
>       if (err) {
>           error_setg(errp, "failed to init SD card: %s",
error_get_pretty(err));
> diff --git a/hw/sd/sd.c b/hw/sd/sd.c
> index be75e118c0..801ddc2cb5 100644
> --- a/hw/sd/sd.c
> +++ b/hw/sd/sd.c
> @@ -93,6 +93,7 @@ struct SDState {
>       /* Configurable properties */
>       BlockBackend *blk;
>       bool spi;
> +    bool validate_crc;

>       uint32_t mode;    /* current card mode, one of SDCardModes */
>       int32_t state;    /* current card state, one of SDCardStates */
> @@ -496,10 +497,12 @@ static bool sd_verify_frame48_checksum(SDFrame48
*frame)
>       return crc == frame->crc;
>   }

> -static int sd_req_crc_validate(SDRequest *req)
> +static bool sd_req_crc_validate(SDState *sd, SDRequest *req)
>   {
> -    return 0;
> -    return !sd_verify_frame48_checksum(req); /* TODO */
> +    if (sd->validate_crc) {
> +        return sd_verify_frame48_checksum(req);
> +    }
> +    return true;
>   }

>   static void sd_update_frame48_checksum(SDFrame48 *frame)
> @@ -1685,7 +1688,7 @@ int sd_do_command(SDState *sd, SDRequest *req,
>           return 0;
>       }

> -    if (sd_req_crc_validate(req)) {
> +    if (!sd_req_crc_validate(sd, req)) {
>           sd->card_status |= COM_CRC_ERROR;
>           rtype = sd_illegal;
>           goto send_response;
> @@ -2134,6 +2137,7 @@ static Property sd_properties[] = {
>        * board to ensure that ssi transfers only occur when the chip select
>        * is asserted.  */
>       DEFINE_PROP_BOOL("spi", SDState, spi, false),
> +    DEFINE_PROP_BOOL("validate-crc", SDState, validate_crc, false),
>       DEFINE_PROP_END_OF_LIST()
>   };

> --
> 2.17.0