s390/uvdevice: Add 'Lock Secret Store' UVC

Userspace can call the Lock Secret Store Ultravisor Call
using IOCTLs on the uvdevice. The Lock Secret Store UV call
disables all additions of secrets for the future.

The uvdevice is merely transporting the request from userspace to the
Ultravisor.

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20230615100533.3996107-6-seiden@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20230615100533.3996107-6-seiden@linux.ibm.com>

diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
index 3739c8f6a1293c0020a3aaadaefbebdd871350a3..3203ffbdde6b87f4e1ff8ca8fe1c0af2af798f3c 100644 (file)
--- 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 76045da44868594890bd73175d9092963649802a..b9c2f14a6af31ae30f5b96228c85f24dc8fb675e 100644 (file)
--- 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 70502c4ec290ab72c7572eae83abf8d3516874d4..144cd2e035909bceac10bd75e00ec9b7b721d6e5 100644 (file)
--- 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);
@@ -340,6 +341,41 @@ 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 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.
+ *
+ * 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)
 {
@@ -390,6 +426,9 @@ 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;