On Wed, 31 Jan 2024, David E. Box wrote:
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
>
> As per SDSi in-band interface specification, sec titled "BIOS lock for
> in-band provisioning", when IB_LOCK bit is set in control qword, the
> SDSI agent is only allowed to perform the read flow, but not allowed to
> provision license blob or license key. So add check for it in
> sdsi_provision().
>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> Signed-off-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
> ---
> drivers/platform/x86/intel/sdsi.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/platform/x86/intel/sdsi.c b/drivers/platform/x86/intel/sdsi.c
> index 14821fee249c..287780fe65bb 100644
> --- a/drivers/platform/x86/intel/sdsi.c
> +++ b/drivers/platform/x86/intel/sdsi.c
> @@ -61,6 +61,7 @@
> #define CTRL_OWNER GENMASK(5, 4)
> #define CTRL_COMPLETE BIT(6)
> #define CTRL_READY BIT(7)
> +#define CTRL_INBAND_LOCK BIT(32)
> #define CTRL_STATUS GENMASK(15, 8)
> #define CTRL_PACKET_SIZE GENMASK(31, 16)
> #define CTRL_MSG_SIZE GENMASK(63, 48)
> @@ -331,12 +332,21 @@ static int sdsi_mbox_read(struct sdsi_priv *priv, struct sdsi_mbox_info *info, s
> return sdsi_mbox_cmd_read(priv, info, data_size);
> }
>
> +static bool sdsi_ib_locked(struct sdsi_priv *priv)
> +{
> + return !!FIELD_GET(CTRL_INBAND_LOCK, readq(priv->control_addr));
> +}
> +
> static ssize_t sdsi_provision(struct sdsi_priv *priv, char *buf, size_t count,
> enum sdsi_command command)
> {
> struct sdsi_mbox_info info = {};
> int ret;
>
> + /* Make sure In-band lock is not set */
> + if (sdsi_ib_locked(priv))
> + return -EPERM;
> +
> if (count > (SDSI_SIZE_WRITE_MSG - SDSI_SIZE_CMD))
> return -EOVERFLOW;
Any reason why this order was chosen? I'd prefer these checks be other way
around (a stupid caller providing too long count gets notified of its
stupidity regardless of the locked state).
--
i.
