linux-kernel - [PATCH v3 4/6] s390/uvdevice: Add 'Lock Secret Store' UVC

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Date:   Tue,  6 Jun 2023 13:37:34 +0200
From:   Steffen Eiden <seiden@...ux.ibm.com>
To:     kvm@...r.kernel.org, linux-s390@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Viktor Mihajlovski <mihajlov@...ux.ibm.com>
Cc:     Janosch Frank <frankja@...ux.ibm.com>,
        Claudio Imbrenda <imbrenda@...ux.ibm.com>,
        Nico Boehr <nrb@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Hendrik Brueckner <brueckner@...ux.ibm.com>
Subject: [PATCH v3 4/6] s390/uvdevice: Add 'Lock Secret Store' UVC

Userspace can call the Lock Secret Store Ultravisor Call
using IOCTLs on the uvdevice.
During the handling of the new IOCTL nr the uvdevice will do some sanity
checks first. Then, perform the Ultravisor command, and copy the
return codes to userspace.
If the Lock Secrets UV facility is not present, UV will return
invalid command rc. This won't be fenced in the driver and does not
result in a negative return value. This is also true for any other
possible error code the UV can return.

Signed-off-by: Steffen Eiden <seiden@...ux.ibm.com>
---
 arch/s390/include/asm/uv.h            |  2 ++
 arch/s390/include/uapi/asm/uvdevice.h |  3 +++
 drivers/s390/char/uvdevice.c          | 39 +++++++++++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
index 3739c8f6a129..3203ffbdde6b 100644
--- a/arch/s390/include/asm/uv.h
+++ b/arch/s390/include/asm/uv.h
@@ -60,6 +60,7 @@
 #define UVC_CMD_RETR_ATTEST		0x1020
 #define UVC_CMD_ADD_SECRET		0x1031
 #define UVC_CMD_LIST_SECRETS		0x1033
+#define UVC_CMD_LOCK_SECRETS		0x1034
 
 /* Bits in installed uv calls */
 enum uv_cmds_inst {
@@ -92,6 +93,7 @@ enum uv_cmds_inst {
 	BIT_UVC_CMD_RETR_ATTEST = 28,
 	BIT_UVC_CMD_ADD_SECRET = 29,
 	BIT_UVC_CMD_LIST_SECRETS = 30,
+	BIT_UVC_CMD_LOCK_SECRETS = 31,
 };
 
 enum uv_feat_ind {
diff --git a/arch/s390/include/uapi/asm/uvdevice.h b/arch/s390/include/uapi/asm/uvdevice.h
index 76045da44868..b9c2f14a6af3 100644
--- a/arch/s390/include/uapi/asm/uvdevice.h
+++ b/arch/s390/include/uapi/asm/uvdevice.h
@@ -80,6 +80,7 @@ enum UVIO_IOCTL_NR {
 	UVIO_IOCTL_ATT_NR,
 	UVIO_IOCTL_ADD_SECRET_NR,
 	UVIO_IOCTL_LIST_SECRETS_NR,
+	UVIO_IOCTL_LOCK_SECRETS_NR,
 	/* must be the last entry */
 	UVIO_IOCTL_NUM_IOCTLS
 };
@@ -89,11 +90,13 @@ enum UVIO_IOCTL_NR {
 #define UVIO_IOCTL_ATT		UVIO_IOCTL(UVIO_IOCTL_ATT_NR)
 #define UVIO_IOCTL_ADD_SECRET	UVIO_IOCTL(UVIO_IOCTL_ADD_SECRET_NR)
 #define UVIO_IOCTL_LIST_SECRETS	UVIO_IOCTL(UVIO_IOCTL_LIST_SECRETS_NR)
+#define UVIO_IOCTL_LOCK_SECRETS	UVIO_IOCTL(UVIO_IOCTL_LOCK_SECRETS_NR)
 
 #define UVIO_SUPP_CALL(nr)	(1ULL << (nr))
 #define UVIO_SUPP_UDEV_INFO	UVIO_SUPP_CALL(UVIO_IOCTL_UDEV_INFO_NR)
 #define UVIO_SUPP_ATT		UVIO_SUPP_CALL(UVIO_IOCTL_ATT_NR)
 #define UVIO_SUPP_ADD_SECRET	UVIO_SUPP_CALL(UVIO_IOCTL_ADD_SECRET_NR)
 #define UVIO_SUPP_LIST_SECRETS	UVIO_SUPP_CALL(UVIO_IOCTL_LIST_SECRETS_NR)
+#define UVIO_SUPP_LOCK_SECRETS	UVIO_SUPP_CALL(UVIO_IOCTL_LOCK_SECRETS_NR)
 
 #endif /* __S390_ASM_UVDEVICE_H */
diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c
index 54a3730f5d0c..8079e15e309c 100644
--- a/drivers/s390/char/uvdevice.c
+++ b/drivers/s390/char/uvdevice.c
@@ -39,6 +39,7 @@ static const u32 ioctl_nr_to_uvc_bit[] __initconst = {
 	[UVIO_IOCTL_ATT_NR] = BIT_UVC_CMD_RETR_ATTEST,
 	[UVIO_IOCTL_ADD_SECRET_NR] = BIT_UVC_CMD_ADD_SECRET,
 	[UVIO_IOCTL_LIST_SECRETS_NR] = BIT_UVC_CMD_LIST_SECRETS,
+	[UVIO_IOCTL_LOCK_SECRETS_NR] = BIT_UVC_CMD_LOCK_SECRETS,
 };
 
 static_assert(ARRAY_SIZE(ioctl_nr_to_uvc_bit) == UVIO_IOCTL_NUM_IOCTLS);
@@ -334,6 +335,41 @@ static int uvio_list_secrets(struct uvio_ioctl_cb *uv_ioctl)
 	return ret;
 }
 
+/** uvio_lock_secrets() - perform a Lock Secret Store UVC
+ * @uv_ioctl: ioctl control block
+ *
+ * uvio_lock_secrets() performs the Lock Secret Store Ultravisor Call. It
+ * performs the UV-call and copies the return codes to the ioctl control block.
+ * After this call was dispatched successfully every following Add Secret UVC
+ * and Lock Secrets UVC will fail with return code 0x102.
+ *
+ * The argument address and size must be 0.
+ *
+ * If the List Secrets UV facility is not present, UV will return invalid
+ * command rc. This won't be fenced in the driver and does not result in a
+ * negative return value.
+ *
+ * Context: might sleep
+ *
+ * Return: 0 on success or a negative error code on error.
+ */
+static int uvio_lock_secrets(struct uvio_ioctl_cb *ioctl)
+{
+	struct uv_cb_nodata uvcb = {
+		.header.len = sizeof(uvcb),
+		.header.cmd = UVC_CMD_LOCK_SECRETS,
+	};
+
+	if (ioctl->argument_addr || ioctl->argument_len)
+		return -EINVAL;
+
+	uv_call(0, (u64)&uvcb);
+	ioctl->uv_rc = uvcb.header.rc;
+	ioctl->uv_rrc = uvcb.header.rrc;
+
+	return 0;
+}
+
 static int uvio_copy_and_check_ioctl(struct uvio_ioctl_cb *ioctl, void __user *argp,
 				     unsigned long cmd)
 {
@@ -384,6 +420,9 @@ static long uvio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	case UVIO_IOCTL_LIST_SECRETS_NR:
 		ret = uvio_list_secrets(&uv_ioctl);
 		break;
+	case UVIO_IOCTL_LOCK_SECRETS_NR:
+		ret = uvio_lock_secrets(&uv_ioctl);
+		break;
 	default:
 		ret = -ENOIOCTLCMD;
 		break;
-- 
2.40.1