linux-kernel - Re: [PATCH v2 4/4] crypto: ccp: When TSME and SME both detected notify user

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Message-ID: <f0a1cb5b-091e-a94b-f767-533f75d0296e@amd.com>
Date:   Thu, 31 Mar 2022 15:12:21 -0500
From:   Tom Lendacky <thomas.lendacky@....com>
To:     Mario Limonciello <mario.limonciello@....com>,
        John Allen <john.allen@....com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S . Miller" <davem@...emloft.net>
Cc:     open list <linux-kernel@...r.kernel.org>,
        "open list:AMD CRYPTOGRAPHIC COPROCESSOR (CCP) DRIVER" 
        <linux-crypto@...r.kernel.org>,
        Kerneis Gabriel <Gabriel.Kerneis@....gouv.fr>,
        Richard Hughes <hughsient@...il.com>
Subject: Re: [PATCH v2 4/4] crypto: ccp: When TSME and SME both detected
 notify user

On 3/29/22 11:41, Mario Limonciello wrote:
> CC_ATTR_HOST_MEM_ENCRYPT is used to relay that memory encryption has been
> activated by the kernel.
> 
> As it's technically possible to enable both SME and TSME at the same time,
> detect this scenario and notify the user that enabling TSME and SME at the
> same time is unnecessary.
> 
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
> v1->v2:
>   * Reword notice about TSME/SME
>   * Use cc_platform_has instead
> ---
>   drivers/crypto/ccp/psp-dev.c | 7 +++++++
>   1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
> index 3f47b2d81e3c..38cffc1de4ab 100644
> --- a/drivers/crypto/ccp/psp-dev.c
> +++ b/drivers/crypto/ccp/psp-dev.c
> @@ -74,6 +74,13 @@ static unsigned int psp_get_capability(struct psp_device *psp)
>   	}
>   	psp->capability = val;
>   
> +

Extra blank line.

> +	/* Detect TSME / SME both enabled */

"Detect if TSME and SME are both enabled"

Thanks,
Tom

> +	if (psp->capability & PSP_CAPABILITY_PSP_SECURITY_REPORTING &&
> +	    psp->capability & (PSP_SECURITY_TSME_STATUS << PSP_CAPABILITY_PSP_SECURITY_OFFSET) &&
> +	    cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
> +		dev_notice(psp->dev, "psp: Both TSME and SME are active, SME is unnecessary when TSME is active.\n");
> +
>   	return 0;
>   }
>