linux-kernel - Re: [PATCH] crypto: ccp: Improve sev_platform

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Date:   Sun, 1 Jan 2023 19:18:30 -0800 (PST)
From:   David Rientjes <rientjes@...gle.com>
To:     Jarkko Sakkinen <jarkko@...fian.com>
cc:     linux-crypto@...r.kernel.org,
        Brijesh Singh <brijesh.singh@....com>,
        Tom Lendacky <thomas.lendacky@....com>,
        John Allen <john.allen@....com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] crypto: ccp: Improve sev_platform_init() error
 messages

On Sat, 31 Dec 2022, Jarkko Sakkinen wrote:

> The following functions end up calling sev_platform_init() or
> __sev_platform_init_locked():
> 
> * sev_guest_init()
> * sev_ioctl_do_pek_csr
> * sev_ioctl_do_pdh_export()
> * sev_ioctl_do_pek_import()
> * sev_ioctl_do_pek_pdh_gen()
> * sev_pci_init()
> 
> However, only sev_pci_init() prints out the failed command error code, and
> even there the error message does not specify, SEV which command failed.
> 
> Address this by printing out the SEV command errors inside
> __sev_platform_init_locked(), and differentiate between DF_FLUSH, INIT and
> INIT_EX commands.
> 
> This extra information is particularly useful if firmware loading and/or
> initialization is going to be made more robust, e.g. by allowing
> firmware loading to be postponed.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko@...fian.com>
> ---
>  drivers/crypto/ccp/sev-dev.c | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index 5350eacaba3a..ac7385c12091 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -963,6 +963,7 @@ static int __sev_init_ex_locked(int *error)
>  
>  static int __sev_platform_init_locked(int *error)
>  {
> +	const char *cmd = sev_init_ex_buffer ? "SEV_CMD_INIT_EX" : "SEV_CMD_INIT";
>  	struct psp_device *psp = psp_master;
>  	struct sev_device *sev;
>  	int rc = 0, psp_ret = -1;

I think this can just be handled directly in the dev_err() since it's only 
used once.

> @@ -1008,18 +1009,23 @@ static int __sev_platform_init_locked(int *error)
>  	if (error)
>  		*error = psp_ret;
>  
> -	if (rc)
> +	if (rc) {
> +		dev_err(sev->dev, "SEV: %s failed error %#x", cmd, psp_ret);
>  		return rc;
> +	}
>  
>  	sev->state = SEV_STATE_INIT;
>  
>  	/* Prepare for first SEV guest launch after INIT */
>  	wbinvd_on_all_cpus();
> -	rc = __sev_do_cmd_locked(SEV_CMD_DF_FLUSH, NULL, error);
> -	if (rc)
> -		return rc;
> +	rc = __sev_do_cmd_locked(SEV_CMD_DF_FLUSH, NULL, &psp_ret);
> +	if (error)
> +		*error = psp_ret;
>  
> -	dev_dbg(sev->dev, "SEV firmware initialized\n");

Any reason to remove this dbg line?  I assume the following dev_info() 
line is deemed sufficient?

> +	if (rc) {
> +		dev_err(sev->dev, "SEV: SEV_CMD_DF_FLUSH failed error %#x", psp_ret);
> +		return rc;
> +	}
>  
>  	dev_info(sev->dev, "SEV API:%d.%d build:%d\n", sev->api_major,
>  		 sev->api_minor, sev->build);
> @@ -2354,8 +2360,7 @@ void sev_pci_init(void)
>  	/* Initialize the platform */
>  	rc = sev_platform_init(&error);
>  	if (rc)
> -		dev_err(sev->dev, "SEV: failed to INIT error %#x, rc %d\n",
> -			error, rc);
> +		dev_err(sev->dev, "SEV: failed to INIT rc %d\n", rc);
>  
>  skip_legacy:
>  	dev_info(sev->dev, "SEV%s API:%d.%d build:%d\n", sev->snp_initialized ?