Commit 33cfb80d authored by Ashish Kalra's avatar Ashish Kalra Committed by Herbert Xu
Browse files

crypto: ccp - Add support for SNP_FEATURE_INFO command 



The FEATURE_INFO command provides hypervisors with a programmatic means
to learn about the supported features of the currently loaded firmware.
This command mimics the CPUID instruction relative to sub-leaf input and
the four unsigned integer output values. To obtain information
regarding the features present in the currently loaded SEV firmware,
use the SNP_FEATURE_INFO command.

Cache the SNP platform status and feature information from CPUID
0x8000_0024 in the sev_device structure. If SNP is enabled, utilize
this cached SNP platform status for the API major, minor and build
version.

Reviewed-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: default avatarAshish Kalra <ashish.kalra@amd.com>
Reviewed-by: default avatarKim Phillips <kim.phillips@amd.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 459daec4

drivers/crypto/ccp/sev-dev.c

+72 −0
Original line number Diff line number Diff line
@@ -233,6 +233,7 @@ static int sev_cmd_buffer_len(int cmd) 
	case SEV_CMD_SNP_GUEST_REQUEST:		return sizeof(struct sev_data_snp_guest_request);

	case SEV_CMD_SNP_CONFIG:		return sizeof(struct sev_user_data_snp_config);

	case SEV_CMD_SNP_COMMIT:		return sizeof(struct sev_data_snp_commit);

	case SEV_CMD_SNP_FEATURE_INFO:		return sizeof(struct sev_data_snp_feature_info);

	default:				return 0;

	}
@@ -1073,6 +1074,67 @@ static void snp_set_hsave_pa(void *arg) 
	wrmsrq(MSR_VM_HSAVE_PA, 0);

}



static int snp_get_platform_data(struct sev_device *sev, int *error)

{

	struct sev_data_snp_feature_info snp_feat_info;

	struct snp_feature_info *feat_info;

	struct sev_data_snp_addr buf;

	struct page *page;

	int rc;



	/*

	 * This function is expected to be called before SNP is

	 * initialized.

	 */

	if (sev->snp_initialized)

		return -EINVAL;



	buf.address = __psp_pa(&sev->snp_plat_status);

	rc = sev_do_cmd(SEV_CMD_SNP_PLATFORM_STATUS, &buf, error);

	if (rc) {

		dev_err(sev->dev, "SNP PLATFORM_STATUS command failed, ret = %d, error = %#x\n",

			rc, *error);

		return rc;

	}



	sev->api_major = sev->snp_plat_status.api_major;

	sev->api_minor = sev->snp_plat_status.api_minor;

	sev->build = sev->snp_plat_status.build_id;



	/*

	 * Do feature discovery of the currently loaded firmware,

	 * and cache feature information from CPUID 0x8000_0024,

	 * sub-function 0.

	 */

	if (!sev->snp_plat_status.feature_info)

		return 0;



	/*

	 * Use dynamically allocated structure for the SNP_FEATURE_INFO

	 * command to ensure structure is 8-byte aligned, and does not

	 * cross a page boundary.

	 */

	page = alloc_page(GFP_KERNEL);

	if (!page)

		return -ENOMEM;



	feat_info = page_address(page);

	snp_feat_info.length = sizeof(snp_feat_info);

	snp_feat_info.ecx_in = 0;

	snp_feat_info.feature_info_paddr = __psp_pa(feat_info);



	rc = sev_do_cmd(SEV_CMD_SNP_FEATURE_INFO, &snp_feat_info, error);

	if (!rc)

		sev->snp_feat_info_0 = *feat_info;

	else

		dev_err(sev->dev, "SNP FEATURE_INFO command failed, ret = %d, error = %#x\n",

			rc, *error);



	__free_page(page);



	return rc;

}



static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg)

{

	struct sev_data_range_list *range_list = arg;
@@ -1599,6 +1661,16 @@ static int sev_get_api_version(void) 
	struct sev_user_data_status status;

	int error = 0, ret;



	/*

	 * Cache SNP platform status and SNP feature information

	 * if SNP is available.

	 */

	if (cc_platform_has(CC_ATTR_HOST_SEV_SNP)) {

		ret = snp_get_platform_data(sev, &error);

		if (ret)

			return 1;

	}



	ret = sev_platform_status(&status, &error);

	if (ret) {

		dev_err(sev->dev,

drivers/crypto/ccp/sev-dev.h

+3 −0
Original line number Diff line number Diff line
@@ -58,6 +58,9 @@ struct sev_device { 
	bool snp_initialized;



	struct sev_user_data_status sev_plat_status;



	struct sev_user_data_snp_status snp_plat_status;

	struct snp_feature_info snp_feat_info_0;

};



int sev_dev_init(struct psp_device *psp);

include/linux/psp-sev.h

+29 −0
Original line number Diff line number Diff line
@@ -107,6 +107,7 @@ enum sev_cmd { 
	SEV_CMD_SNP_DOWNLOAD_FIRMWARE_EX = 0x0CA,

	SEV_CMD_SNP_COMMIT		= 0x0CB,

	SEV_CMD_SNP_VLEK_LOAD		= 0x0CD,

	SEV_CMD_SNP_FEATURE_INFO	= 0x0CE,



	SEV_CMD_MAX,

};
@@ -814,6 +815,34 @@ struct sev_data_snp_commit { 
	u32 len;

} __packed;



/**

 * struct sev_data_snp_feature_info - SEV_SNP_FEATURE_INFO structure

 *

 * @length: len of the command buffer read by the PSP

 * @ecx_in: subfunction index

 * @feature_info_paddr : System Physical Address of the FEATURE_INFO structure

 */

struct sev_data_snp_feature_info {

	u32 length;

	u32 ecx_in;

	u64 feature_info_paddr;

} __packed;



/**

 * struct feature_info - FEATURE_INFO structure

 *

 * @eax: output of SNP_FEATURE_INFO command

 * @ebx: output of SNP_FEATURE_INFO command

 * @ecx: output of SNP_FEATURE_INFO command

 * #edx: output of SNP_FEATURE_INFO command

 */

struct snp_feature_info {

	u32 eax;

	u32 ebx;

	u32 ecx;

	u32 edx;

} __packed;



#ifdef CONFIG_CRYPTO_DEV_SP_PSP



/**