sed-opal: Add command to read locking range parameters.

It returns following attributes:

locking range start
locking range length
read lock enabled
write lock enabled
lock state (RW, RO or LK)

It can be retrieved by user authority provided the authority
was added to locking range via prior IOC_OPAL_ADD_USR_TO_LR
ioctl command. The command was extended to add user in ACE that
allows to read attributes listed above.

Signed-off-by: Ondrej Kozina <okozina@redhat.com>
Tested-by: Luca Boccassi <bluca@debian.org>
Tested-by: Milan Broz <gmazyland@gmail.com>
Link: https://lore.kernel.org/r/20230405111223.272816-6-okozina@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/sed-opal.c

@@ -1445,6 +1445,129 @@ static int setup_locking_range(struct opal_dev *dev, void *data)
 	return finalize_and_send(dev, parse_and_check_status);
 }
 
+static int response_get_column(const struct parsed_resp *resp,
+			       int *iter,
+			       u8 column,
+			       u64 *value)
+{
+	const struct opal_resp_tok *tok;
+	int n = *iter;
+	u64 val;
+
+	tok = response_get_token(resp, n);
+	if (IS_ERR(tok))
+		return PTR_ERR(tok);
+
+	if (!response_token_matches(tok, OPAL_STARTNAME)) {
+		pr_debug("Unexpected response token type %d.\n", n);
+		return OPAL_INVAL_PARAM;
+	}
+	n++;
+
+	if (response_get_u64(resp, n) != column) {
+		pr_debug("Token %d does not match expected column %u.\n",
+			 n, column);
+		return OPAL_INVAL_PARAM;
+	}
+	n++;
+
+	val = response_get_u64(resp, n);
+	n++;
+
+	tok = response_get_token(resp, n);
+	if (IS_ERR(tok))
+		return PTR_ERR(tok);
+
+	if (!response_token_matches(tok, OPAL_ENDNAME)) {
+		pr_debug("Unexpected response token type %d.\n", n);
+		return OPAL_INVAL_PARAM;
+	}
+	n++;
+
+	*value = val;
+	*iter = n;
+
+	return 0;
+}
+
+static int locking_range_status(struct opal_dev *dev, void *data)
+{
+	u8 lr_buffer[OPAL_UID_LENGTH];
+	u64 resp;
+	bool rlocked, wlocked;
+	int err, tok_n = 2;
+	struct opal_lr_status *lrst = data;
+
+	err = build_locking_range(lr_buffer, sizeof(lr_buffer),
+				  lrst->session.opal_key.lr);
+	if (err)
+		return err;
+
+	err = generic_get_columns(dev, lr_buffer, OPAL_RANGESTART,
+				  OPAL_WRITELOCKED);
+	if (err) {
+		pr_debug("Couldn't get lr %u table columns %d to %d.\n",
+			 lrst->session.opal_key.lr, OPAL_RANGESTART,
+			 OPAL_WRITELOCKED);
+		return err;
+	}
+
+	/* range start */
+	err = response_get_column(&dev->parsed, &tok_n, OPAL_RANGESTART,
+				  &lrst->range_start);
+	if (err)
+		return err;
+
+	/* range length */
+	err = response_get_column(&dev->parsed, &tok_n, OPAL_RANGELENGTH,
+				  &lrst->range_length);
+	if (err)
+		return err;
+
+	/* RLE */
+	err = response_get_column(&dev->parsed, &tok_n, OPAL_READLOCKENABLED,
+				  &resp);
+	if (err)
+		return err;
+
+	lrst->RLE = !!resp;
+
+	/* WLE */
+	err = response_get_column(&dev->parsed, &tok_n, OPAL_WRITELOCKENABLED,
+				  &resp);
+	if (err)
+		return err;
+
+	lrst->WLE = !!resp;
+
+	/* read locked */
+	err = response_get_column(&dev->parsed, &tok_n, OPAL_READLOCKED, &resp);
+	if (err)
+		return err;
+
+	rlocked = !!resp;
+
+	/* write locked */
+	err = response_get_column(&dev->parsed, &tok_n, OPAL_WRITELOCKED, &resp);
+	if (err)
+		return err;
+
+	wlocked = !!resp;
+
+	/* opal_lock_state can not map 'read locked' only state. */
+	lrst->l_state = OPAL_RW;
+	if (rlocked && wlocked)
+		lrst->l_state = OPAL_LK;
+	else if (wlocked)
+		lrst->l_state = OPAL_RO;
+	else if (rlocked) {
+		pr_debug("Can not report read locked only state.\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int start_generic_opal_session(struct opal_dev *dev,
 				      enum opal_uid auth,
 				      enum opal_uid sp_type,
@@ -2642,6 +2765,33 @@ static int opal_setup_locking_range(struct opal_dev *dev,
 	return ret;
 }
 
+static int opal_locking_range_status(struct opal_dev *dev,
+			  struct opal_lr_status *opal_lrst,
+			  void __user *data)
+{
+	const struct opal_step lr_steps[] = {
+		{ start_auth_opal_session, &opal_lrst->session },
+		{ locking_range_status, opal_lrst },
+		{ end_opal_session, }
+	};
+	int ret;
+
+	mutex_lock(&dev->dev_lock);
+	setup_opal_dev(dev);
+	ret = execute_steps(dev, lr_steps, ARRAY_SIZE(lr_steps));
+	mutex_unlock(&dev->dev_lock);
+
+	/* skip session info when copying back to uspace */
+	if (!ret && copy_to_user(data + offsetof(struct opal_lr_status, range_start),
+				(void *)opal_lrst + offsetof(struct opal_lr_status, range_start),
+				sizeof(*opal_lrst) - offsetof(struct opal_lr_status, range_start))) {
+		pr_debug("Error copying status to userspace\n");
+		return -EFAULT;
+	}
+
+	return ret;
+}
+
 static int opal_set_new_pw(struct opal_dev *dev, struct opal_new_pw *opal_pw)
 {
 	const struct opal_step pw_steps[] = {
@@ -2876,6 +3026,9 @@ int sed_ioctl(struct opal_dev *dev, unsigned int cmd, void __user *arg)
 	case IOC_OPAL_GET_STATUS:
 		ret = opal_get_status(dev, arg);
 		break;
+	case IOC_OPAL_GET_LR_STATUS:
+		ret = opal_locking_range_status(dev, p, arg);
+		break;
 	default:
 		break;
 	}

include/linux/sed-opal.h

@@ -45,6 +45,7 @@ static inline bool is_sed_ioctl(unsigned int cmd)
 	case IOC_OPAL_WRITE_SHADOW_MBR:
 	case IOC_OPAL_GENERIC_TABLE_RW:
 	case IOC_OPAL_GET_STATUS:
+	case IOC_OPAL_GET_LR_STATUS:
 		return true;
 	}
 	return false;

include/uapi/linux/sed-opal.h

@@ -78,6 +78,16 @@ struct opal_user_lr_setup {
 	struct opal_session_info session;
 };
 
+struct opal_lr_status {
+	struct opal_session_info session;
+	__u64 range_start;
+	__u64 range_length;
+	__u32 RLE; /* Read Lock enabled */
+	__u32 WLE; /* Write Lock Enabled */
+	__u32 l_state;
+	__u8  align[4];
+};
+
 struct opal_lock_unlock {
 	struct opal_session_info session;
 	__u32 l_state;
@@ -168,5 +178,6 @@ struct opal_status {
 #define IOC_OPAL_WRITE_SHADOW_MBR   _IOW('p', 234, struct opal_shadow_mbr)
 #define IOC_OPAL_GENERIC_TABLE_RW   _IOW('p', 235, struct opal_read_write_table)
 #define IOC_OPAL_GET_STATUS         _IOR('p', 236, struct opal_status)
+#define IOC_OPAL_GET_LR_STATUS      _IOW('p', 237, struct opal_lr_status)
 
 #endif /* _UAPI_SED_OPAL_H */