linux-kernel - Re: [PATCH V2 3/9] platform/x86/intel/sdsi: Add in-band BIOS lock support

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Date: Mon, 4 Mar 2024 15:26:12 +0200 (EET)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: "David E. Box" <david.e.box@...ux.intel.com>
cc: rajvi.jingar@...ux.intel.com, platform-driver-x86@...r.kernel.org, 
    linux-kernel@...r.kernel.org, hdegoede@...hat.com, 
    ilpo.jarvinen@...ux.intel.com
Subject: Re: [PATCH V2 3/9] platform/x86/intel/sdsi: Add in-band BIOS lock
 support

On Tue, 27 Feb 2024, David E. Box wrote:

> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
> 
> 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@...ux.intel.com>
> Signed-off-by: David E. Box <david.e.box@...ux.intel.com>
> ---
> 
> V2 - Move sdsi_ib_locked() check after overflow check
> 
>  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 d80c2dc0ce71..bb3eaf5eb382 100644
> --- a/drivers/platform/x86/intel/sdsi.c
> +++ b/drivers/platform/x86/intel/sdsi.c
> @@ -67,6 +67,7 @@
>  #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)
> @@ -346,6 +347,11 @@ 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)
>  {
> @@ -355,6 +361,10 @@ static ssize_t sdsi_provision(struct sdsi_priv *priv, char *buf, size_t count,
>  	if (count > (SDSI_SIZE_WRITE_MSG - SDSI_SIZE_CMD))
>  		return -EOVERFLOW;
>  
> +	/* Make sure In-band lock is not set */
> +	if (sdsi_ib_locked(priv))
> +		return -EPERM;
> +

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>

-- 
 i.