crypto: ccp - Add GET_ID SEV command

The GET_ID command, added as of SEV API v0.16, allows the SEV firmware
to be queried about a unique CPU ID. This unique ID can then be used
to obtain the public certificate containing the Chip Endorsement Key
(CEK) public key signed by the AMD SEV Signing Key (ASK).

For more information please refer to "Section 5.12 GET_ID" of
https://support.amd.com/TechDocs/55766_SEV-KM%20API_Specification.pdf

Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 44 insertions, 0 deletions

diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
index 12838b406696..ff478d826d7d 100644
--- a/drivers/crypto/ccp/psp-dev.c
+++ b/drivers/crypto/ccp/psp-dev.c
@@ -119,6 +119,7 @@ static int sev_cmd_buffer_len(int cmd)
 	case SEV_CMD_RECEIVE_UPDATE_VMSA:	return sizeof(struct sev_data_receive_update_vmsa);
 	case SEV_CMD_LAUNCH_UPDATE_SECRET:	return sizeof(struct sev_data_launch_secret);
 	case SEV_CMD_DOWNLOAD_FIRMWARE:		return sizeof(struct sev_data_download_firmware);
+	case SEV_CMD_GET_ID:			return sizeof(struct sev_data_get_id);
 	default:				return 0;
 	}
 
@@ -510,6 +511,46 @@ e_free:
 	return ret;
 }
 
+static int sev_ioctl_do_get_id(struct sev_issue_cmd *argp)
+{
+	struct sev_data_get_id *data;
+	u64 data_size, user_size;
+	void *id_blob, *mem;
+	int ret;
+
+	/* SEV GET_ID available from SEV API v0.16 and up */
+	if (!SEV_VERSION_GREATER_OR_EQUAL(0, 16))
+		return -ENOTSUPP;
+
+	/* SEV FW expects the buffer it fills with the ID to be
+	 * 8-byte aligned. Memory allocated should be enough to
+	 * hold data structure + alignment padding + memory
+	 * where SEV FW writes the ID.
+	 */
+	data_size = ALIGN(sizeof(struct sev_data_get_id), 8);
+	user_size = sizeof(struct sev_user_data_get_id);
+
+	mem = kzalloc(data_size + user_size, GFP_KERNEL);
+	if (!mem)
+		return -ENOMEM;
+
+	data = mem;
+	id_blob = mem + data_size;
+
+	data->address = __psp_pa(id_blob);
+	data->len = user_size;
+
+	ret = __sev_do_cmd_locked(SEV_CMD_GET_ID, data, &argp->error);
+	if (!ret) {
+		if (copy_to_user((void __user *)argp->data, id_blob, data->len))
+			ret = -EFAULT;
+	}
+
+	kfree(mem);
+
+	return ret;
+}
+
 static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp)
 {
 	struct sev_user_data_pdh_cert_export input;
@@ -647,6 +688,9 @@ static long sev_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
 	case SEV_PDH_CERT_EXPORT:
 		ret = sev_ioctl_do_pdh_export(&input);
 		break;
+	case SEV_GET_ID:
+		ret = sev_ioctl_do_get_id(&input);
+		break;
 	default:
 		ret = -EINVAL;
 		goto out;