Re: [PATCH v2] crypto: ccp: Sanitize sev_platform_init() error messages

[Tom Lendacky <thomas.lendacky@amd.com>]

On 1/8/23 14:24, 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.

event there, the error message does not specify which SEV 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.  As a side-effect, @error can be removed from the
> parameter list.
> 
> 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@profian.com>
> ---
> v2:
> * Address David Rientjes's feedback:
>    https://lore.kernel.org/all/6a16bbe4-4281-fb28-78c4-4ec44c8aa679@google.com/
> * Remove @error.
> * Remove "SEV_" prefix: it is obvious from context so no need to make klog
>    line longer.
> ---
>   arch/x86/kvm/svm/sev.c       |  2 +-
>   drivers/crypto/ccp/sev-dev.c | 33 +++++++++++++++++----------------
>   include/linux/psp-sev.h      |  4 +---
>   3 files changed, 19 insertions(+), 20 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index efaaef2b7ae1..42e6bd637896 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -254,7 +254,7 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
>   		goto e_no_asid;
>   	sev->asid = asid;
>   
> -	ret = sev_platform_init(&argp->error);
> +	ret = sev_platform_init();
>   	if (ret)
>   		goto e_free;
>   
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index 06fc7156c04f..3b66cb1495d4 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -440,7 +440,7 @@ static int __sev_init_ex_locked(int *error)
>   	return __sev_do_cmd_locked(SEV_CMD_INIT_EX, &data, error);
>   }
>   
> -static int __sev_platform_init_locked(int *error)
> +static int __sev_platform_init_locked(void)

Why is this being removed. Userspace may still want to see this. Some of 
the error pointers are from the ioctl() arguments...

>   {
>   	struct psp_device *psp = psp_master;
>   	struct sev_device *sev;
> @@ -476,19 +476,21 @@ static int __sev_platform_init_locked(int *error)
>   		dev_err(sev->dev, "SEV: retrying INIT command because of SECURE_DATA_INVALID error. Retrying once to reset PSP SEV state.");
>   		rc = init_function(&psp_ret);
>   	}
> -	if (error)
> -		*error = psp_ret;
> -
> -	if (rc)
> +	if (rc) {
> +		dev_err(sev->dev, "SEV: %s failed error %#x",
> +			sev_init_ex_buffer ? "CMD_INIT_EX" : "CMD_INIT", 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)
> +	rc = __sev_do_cmd_locked(SEV_CMD_DF_FLUSH, NULL, &psp_ret);
> +	if (rc) {
> +		dev_err(sev->dev, "SEV: CMD_DF_FLUSH failed error %#x", psp_ret);
>   		return rc;
> +	}
>   
>   	dev_dbg(sev->dev, "SEV firmware initialized\n");
>   
> @@ -498,12 +500,12 @@ static int __sev_platform_init_locked(int *error)
>   	return 0;
>   }
>   
> -int sev_platform_init(int *error)
> +int sev_platform_init(void)
>   {
>   	int rc;
>   
>   	mutex_lock(&sev_cmd_mutex);
> -	rc = __sev_platform_init_locked(error);
> +	rc = __sev_platform_init_locked();
>   	mutex_unlock(&sev_cmd_mutex);
>   
>   	return rc;
> @@ -610,7 +612,7 @@ static int sev_ioctl_do_pek_pdh_gen(int cmd, struct sev_issue_cmd *argp, bool wr
>   		return -EPERM;
>   
>   	if (sev->state == SEV_STATE_UNINIT) {
> -		rc = __sev_platform_init_locked(&argp->error);
> +		rc = __sev_platform_init_locked();

... like here. So I don't think that should be removed.

Thanks,
Tom

>   		if (rc)
>   			return rc;
>   	}
> @@ -653,7 +655,7 @@ static int sev_ioctl_do_pek_csr(struct sev_issue_cmd *argp, bool writable)
>   
>   cmd:
>   	if (sev->state == SEV_STATE_UNINIT) {
> -		ret = __sev_platform_init_locked(&argp->error);
> +		ret = __sev_platform_init_locked();
>   		if (ret)
>   			goto e_free_blob;
>   	}
> @@ -849,7 +851,7 @@ static int sev_ioctl_do_pek_import(struct sev_issue_cmd *argp, bool writable)
>   
>   	/* If platform is not in INIT state then transition it to INIT */
>   	if (sev->state != SEV_STATE_INIT) {
> -		ret = __sev_platform_init_locked(&argp->error);
> +		ret = __sev_platform_init_locked();
>   		if (ret)
>   			goto e_free_oca;
>   	}
> @@ -973,7 +975,7 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
>   		if (!writable)
>   			return -EPERM;
>   
> -		ret = __sev_platform_init_locked(&argp->error);
> +		ret = __sev_platform_init_locked();
>   		if (ret)
>   			return ret;
>   	}
> @@ -1335,10 +1337,9 @@ void sev_pci_init(void)
>   		return;
>   
>   	/* Initialize the platform */
> -	rc = sev_platform_init(&error);
> +	rc = sev_platform_init();
>   	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);
>   
>   	return;
>   
> diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
> index 1595088c428b..2f8681b753d0 100644
> --- a/include/linux/psp-sev.h
> +++ b/include/linux/psp-sev.h
> @@ -536,8 +536,6 @@ struct sev_data_attestation_report {
>   /**
>    * sev_platform_init - perform SEV INIT command
>    *
> - * @error: SEV command return code
> - *
>    * Returns:
>    * 0 if the SEV successfully processed the command
>    * -%ENODEV    if the SEV device is not available
> @@ -545,7 +543,7 @@ struct sev_data_attestation_report {
>    * -%ETIMEDOUT if the SEV command timed out
>    * -%EIO       if the SEV returned a non-zero return code
>    */
> -int sev_platform_init(int *error);
> +int sev_platform_init(void);
>   
>   /**
>    * sev_platform_status - perform SEV PLATFORM_STATUS command