Re: [PATCH v6 3/8] crypto: ccp: Ensure implicit SEV/SNP init and shutdown in ioctls

[Tom Lendacky]

On 3/6/25 17:10, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@xxxxxxx>
> 
> Modify the behavior of implicit SEV initialization in some of the
> SEV ioctls to do both SEV initialization and shutdown and add
> implicit SNP initialization and shutdown to some of the SNP ioctls
> so that the change of SEV/SNP platform initialization not being
> done during PSP driver probe time does not break userspace tools
> such as sevtool, etc.
> 
> Prior to this patch, SEV has always been initialized before these
> ioctls as SEV initialization is done as part of PSP module probe,
> but now with SEV initialization being moved to KVM module load instead
> of PSP driver probe, the implied SEV INIT actually makes sense and gets
> used and additionally to maintain SEV platform state consistency
> before and after the ioctl SEV shutdown needs to be done after the
> firmware call.
> 
> It is important to do SEV Shutdown here with the SEV/SNP initialization
> moving to KVM, an implicit SEV INIT here as part of the SEV ioctls not
> followed with SEV Shutdown will cause SEV to remain in INIT state and
> then a future SNP INIT in KVM module load will fail.
> 
> Also ensure that for these SEV ioctls both implicit SNP and SEV INIT is
> done followed by both SEV and SNP shutdown as RMP table must be
> initialized before calling SEV INIT if SNP host support is enabled.
> 
> Similarly, prior to this patch, SNP has always been initialized before
> these ioctls as SNP initialization is done as part of PSP module probe,
> therefore, to keep a consistent behavior, SNP init needs to be done
> here implicitly as part of these ioctls followed with SNP shutdown
> before returning from the ioctl to maintain the consistent platform
> state before and after the ioctl.
> 
> Suggested-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>

Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx>

> ---
>  drivers/crypto/ccp/sev-dev.c | 142 +++++++++++++++++++++++++++++------
>  1 file changed, 119 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index ccd7cc4b36d1..5bd3df377370 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -109,6 +109,8 @@ static void *sev_init_ex_buffer;
>   */
>  static struct sev_data_range_list *snp_range_list;
>  
> +static void __sev_firmware_shutdown(struct sev_device *sev, bool panic);
> +
>  static inline bool sev_version_greater_or_equal(u8 maj, u8 min)
>  {
>  	struct sev_device *sev = psp_master->sev_data;
> @@ -1402,6 +1404,37 @@ static int sev_get_platform_state(int *state, int *error)
>  	return rc;
>  }
>  
> +static int sev_move_to_init_state(struct sev_issue_cmd *argp, bool *shutdown_required)
> +{
> +	struct sev_platform_init_args init_args = {0};
> +	int rc;
> +
> +	rc = _sev_platform_init_locked(&init_args);
> +	if (rc) {
> +		argp->error = SEV_RET_INVALID_PLATFORM_STATE;
> +		return rc;
> +	}
> +
> +	*shutdown_required = true;
> +
> +	return 0;
> +}
> +
> +static int snp_move_to_init_state(struct sev_issue_cmd *argp, bool *shutdown_required)
> +{
> +	int error, rc;
> +
> +	rc = __sev_snp_init_locked(&error);
> +	if (rc) {
> +		argp->error = SEV_RET_INVALID_PLATFORM_STATE;
> +		return rc;
> +	}
> +
> +	*shutdown_required = true;
> +
> +	return 0;
> +}
> +
>  static int sev_ioctl_do_reset(struct sev_issue_cmd *argp, bool writable)
>  {
>  	int state, rc;
> @@ -1454,24 +1487,31 @@ static int sev_ioctl_do_platform_status(struct sev_issue_cmd *argp)
>  static int sev_ioctl_do_pek_pdh_gen(int cmd, struct sev_issue_cmd *argp, bool writable)
>  {
>  	struct sev_device *sev = psp_master->sev_data;
> +	bool shutdown_required = false;
>  	int rc;
>  
>  	if (!writable)
>  		return -EPERM;
>  
>  	if (sev->state == SEV_STATE_UNINIT) {
> -		rc = __sev_platform_init_locked(&argp->error);
> +		rc = sev_move_to_init_state(argp, &shutdown_required);
>  		if (rc)
>  			return rc;
>  	}
>  
> -	return __sev_do_cmd_locked(cmd, NULL, &argp->error);
> +	rc = __sev_do_cmd_locked(cmd, NULL, &argp->error);
> +
> +	if (shutdown_required)
> +		__sev_firmware_shutdown(sev, false);
> +
> +	return rc;
>  }
>  
>  static int sev_ioctl_do_pek_csr(struct sev_issue_cmd *argp, bool writable)
>  {
>  	struct sev_device *sev = psp_master->sev_data;
>  	struct sev_user_data_pek_csr input;
> +	bool shutdown_required = false;
>  	struct sev_data_pek_csr data;
>  	void __user *input_address;
>  	void *blob = NULL;
> @@ -1503,7 +1543,7 @@ 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_move_to_init_state(argp, &shutdown_required);
>  		if (ret)
>  			goto e_free_blob;
>  	}
> @@ -1524,6 +1564,9 @@ static int sev_ioctl_do_pek_csr(struct sev_issue_cmd *argp, bool writable)
>  	}
>  
>  e_free_blob:
> +	if (shutdown_required)
> +		__sev_firmware_shutdown(sev, false);
> +
>  	kfree(blob);
>  	return ret;
>  }
> @@ -1743,6 +1786,7 @@ static int sev_ioctl_do_pek_import(struct sev_issue_cmd *argp, bool writable)
>  	struct sev_device *sev = psp_master->sev_data;
>  	struct sev_user_data_pek_cert_import input;
>  	struct sev_data_pek_cert_import data;
> +	bool shutdown_required = false;
>  	void *pek_blob, *oca_blob;
>  	int ret;
>  
> @@ -1773,7 +1817,7 @@ 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_move_to_init_state(argp, &shutdown_required);
>  		if (ret)
>  			goto e_free_oca;
>  	}
> @@ -1781,6 +1825,9 @@ static int sev_ioctl_do_pek_import(struct sev_issue_cmd *argp, bool writable)
>  	ret = __sev_do_cmd_locked(SEV_CMD_PEK_CERT_IMPORT, &data, &argp->error);
>  
>  e_free_oca:
> +	if (shutdown_required)
> +		__sev_firmware_shutdown(sev, false);
> +
>  	kfree(oca_blob);
>  e_free_pek:
>  	kfree(pek_blob);
> @@ -1897,18 +1944,9 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
>  	struct sev_data_pdh_cert_export data;
>  	void __user *input_cert_chain_address;
>  	void __user *input_pdh_cert_address;
> +	bool shutdown_required = false;
>  	int ret;
>  
> -	/* If platform is not in INIT state then transition it to INIT. */
> -	if (sev->state != SEV_STATE_INIT) {
> -		if (!writable)
> -			return -EPERM;
> -
> -		ret = __sev_platform_init_locked(&argp->error);
> -		if (ret)
> -			return ret;
> -	}
> -
>  	if (copy_from_user(&input, (void __user *)argp->data, sizeof(input)))
>  		return -EFAULT;
>  
> @@ -1948,6 +1986,17 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
>  	data.cert_chain_len = input.cert_chain_len;
>  
>  cmd:
> +	/* If platform is not in INIT state then transition it to INIT. */
> +	if (sev->state != SEV_STATE_INIT) {
> +		if (!writable) {
> +			ret = -EPERM;
> +			goto e_free_cert;
> +		}
> +		ret = sev_move_to_init_state(argp, &shutdown_required);
> +		if (ret)
> +			goto e_free_cert;
> +	}
> +
>  	ret = __sev_do_cmd_locked(SEV_CMD_PDH_CERT_EXPORT, &data, &argp->error);
>  
>  	/* If we query the length, FW responded with expected data. */
> @@ -1974,6 +2023,9 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
>  	}
>  
>  e_free_cert:
> +	if (shutdown_required)
> +		__sev_firmware_shutdown(sev, false);
> +
>  	kfree(cert_blob);
>  e_free_pdh:
>  	kfree(pdh_blob);
> @@ -1983,12 +2035,13 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
>  static int sev_ioctl_do_snp_platform_status(struct sev_issue_cmd *argp)
>  {
>  	struct sev_device *sev = psp_master->sev_data;
> +	bool shutdown_required = false;
>  	struct sev_data_snp_addr buf;
>  	struct page *status_page;
> +	int ret, error;
>  	void *data;
> -	int ret;
>  
> -	if (!sev->snp_initialized || !argp->data)
> +	if (!argp->data)
>  		return -EINVAL;
>  
>  	status_page = alloc_page(GFP_KERNEL_ACCOUNT);
> @@ -1997,6 +2050,12 @@ static int sev_ioctl_do_snp_platform_status(struct sev_issue_cmd *argp)
>  
>  	data = page_address(status_page);
>  
> +	if (!sev->snp_initialized) {
> +		ret = snp_move_to_init_state(argp, &shutdown_required);
> +		if (ret)
> +			goto cleanup;
> +	}
> +
>  	/*
>  	 * Firmware expects status page to be in firmware-owned state, otherwise
>  	 * it will report firmware error code INVALID_PAGE_STATE (0x1A).
> @@ -2025,6 +2084,9 @@ static int sev_ioctl_do_snp_platform_status(struct sev_issue_cmd *argp)
>  		ret = -EFAULT;
>  
>  cleanup:
> +	if (shutdown_required)
> +		__sev_snp_shutdown_locked(&error, false);
> +
>  	__free_pages(status_page, 0);
>  	return ret;
>  }
> @@ -2033,21 +2095,33 @@ static int sev_ioctl_do_snp_commit(struct sev_issue_cmd *argp)
>  {
>  	struct sev_device *sev = psp_master->sev_data;
>  	struct sev_data_snp_commit buf;
> +	bool shutdown_required = false;
> +	int ret, error;
>  
> -	if (!sev->snp_initialized)
> -		return -EINVAL;
> +	if (!sev->snp_initialized) {
> +		ret = snp_move_to_init_state(argp, &shutdown_required);
> +		if (ret)
> +			return ret;
> +	}
>  
>  	buf.len = sizeof(buf);
>  
> -	return __sev_do_cmd_locked(SEV_CMD_SNP_COMMIT, &buf, &argp->error);
> +	ret = __sev_do_cmd_locked(SEV_CMD_SNP_COMMIT, &buf, &argp->error);
> +
> +	if (shutdown_required)
> +		__sev_snp_shutdown_locked(&error, false);
> +
> +	return ret;
>  }
>  
>  static int sev_ioctl_do_snp_set_config(struct sev_issue_cmd *argp, bool writable)
>  {
>  	struct sev_device *sev = psp_master->sev_data;
>  	struct sev_user_data_snp_config config;
> +	bool shutdown_required = false;
> +	int ret, error;
>  
> -	if (!sev->snp_initialized || !argp->data)
> +	if (!argp->data)
>  		return -EINVAL;
>  
>  	if (!writable)
> @@ -2056,17 +2130,29 @@ static int sev_ioctl_do_snp_set_config(struct sev_issue_cmd *argp, bool writable
>  	if (copy_from_user(&config, (void __user *)argp->data, sizeof(config)))
>  		return -EFAULT;
>  
> -	return __sev_do_cmd_locked(SEV_CMD_SNP_CONFIG, &config, &argp->error);
> +	if (!sev->snp_initialized) {
> +		ret = snp_move_to_init_state(argp, &shutdown_required);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = __sev_do_cmd_locked(SEV_CMD_SNP_CONFIG, &config, &argp->error);
> +
> +	if (shutdown_required)
> +		__sev_snp_shutdown_locked(&error, false);
> +
> +	return ret;
>  }
>  
>  static int sev_ioctl_do_snp_vlek_load(struct sev_issue_cmd *argp, bool writable)
>  {
>  	struct sev_device *sev = psp_master->sev_data;
>  	struct sev_user_data_snp_vlek_load input;
> +	bool shutdown_required = false;
> +	int ret, error;
>  	void *blob;
> -	int ret;
>  
> -	if (!sev->snp_initialized || !argp->data)
> +	if (!argp->data)
>  		return -EINVAL;
>  
>  	if (!writable)
> @@ -2085,8 +2171,18 @@ static int sev_ioctl_do_snp_vlek_load(struct sev_issue_cmd *argp, bool writable)
>  
>  	input.vlek_wrapped_address = __psp_pa(blob);
>  
> +	if (!sev->snp_initialized) {
> +		ret = snp_move_to_init_state(argp, &shutdown_required);
> +		if (ret)
> +			goto cleanup;
> +	}
> +
>  	ret = __sev_do_cmd_locked(SEV_CMD_SNP_VLEK_LOAD, &input, &argp->error);
>  
> +	if (shutdown_required)
> +		__sev_snp_shutdown_locked(&error, false);
> +
> +cleanup:
>  	kfree(blob);
>  
>  	return ret;