Commit eaa517b7 authored by Ido Schimmel's avatar Ido Schimmel Committed by Paolo Abeni
Browse files

ethtool: cmis_cdb: Fix incorrect read / write length extension 



The 'read_write_len_ext' field in 'struct ethtool_cmis_cdb_cmd_args'
stores the maximum number of bytes that can be read from or written to
the Local Payload (LPL) page in a single multi-byte access.

Cited commit started overwriting this field with the maximum number of
bytes that can be read from or written to the Extended Payload (LPL)
pages in a single multi-byte access. Transceiver modules that support
auto paging can advertise a number larger than 255 which is problematic
as 'read_write_len_ext' is a 'u8', resulting in the number getting
truncated and firmware flashing failing [1].

Fix by ignoring the maximum EPL access size as the kernel does not
currently support auto paging (even if the transceiver module does) and
will not try to read / write more than 128 bytes at once.

[1]
Transceiver module firmware flashing started for device enp177s0np0
Transceiver module firmware flashing in progress for device enp177s0np0
Progress: 0%
Transceiver module firmware flashing encountered an error for device enp177s0np0
Status message: Write FW block EPL command failed, LPL length is longer
	than CDB read write length extension allows.

Fixes: 9a3b0d07 ("net: ethtool: Add support for writing firmware blocks using EPL payload")
Reported-by: default avatarDamodharam Ammepalli <damodharam.ammepalli@broadcom.com>
Closes: https://lore.kernel.org/netdev/20250402183123.321036-3-michael.chan@broadcom.com/


Tested-by: default avatarDamodharam Ammepalli <damodharam.ammepalli@broadcom.com>
Signed-off-by: default avatarIdo Schimmel <idosch@nvidia.com>
Reviewed-by: default avatarDamodharam Ammepalli <damodharam.ammepalli@broadcom.com>
Reviewed-by: default avatarPetr Machata <petrm@nvidia.com>
Link: https://patch.msgid.link/20250409112440.365672-1-idosch@nvidia.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 69ddc652

net/ethtool/cmis.h

+0 −1
Original line number Diff line number Diff line
@@ -101,7 +101,6 @@ struct ethtool_cmis_cdb_rpl { 
};



u32 ethtool_cmis_get_max_lpl_size(u8 num_of_byte_octs);

u32 ethtool_cmis_get_max_epl_size(u8 num_of_byte_octs);



void ethtool_cmis_cdb_compose_args(struct ethtool_cmis_cdb_cmd_args *args,

				   enum ethtool_cmis_cdb_cmd_id cmd, u8 *lpl,

net/ethtool/cmis_cdb.c

+3 −15
Original line number Diff line number Diff line
@@ -16,15 +16,6 @@ u32 ethtool_cmis_get_max_lpl_size(u8 num_of_byte_octs) 
	return 8 * (1 + min_t(u8, num_of_byte_octs, 15));

}



/* For accessing the EPL field on page 9Fh, the allowable length extension is

 * min(i, 255) byte octets where i specifies the allowable additional number of

 * byte octets in a READ or a WRITE.

 */

u32 ethtool_cmis_get_max_epl_size(u8 num_of_byte_octs)

{

	return 8 * (1 + min_t(u8, num_of_byte_octs, 255));

}



void ethtool_cmis_cdb_compose_args(struct ethtool_cmis_cdb_cmd_args *args,

				   enum ethtool_cmis_cdb_cmd_id cmd, u8 *lpl,

				   u8 lpl_len, u8 *epl, u16 epl_len,
@@ -33,19 +24,16 @@ void ethtool_cmis_cdb_compose_args(struct ethtool_cmis_cdb_cmd_args *args, 
{

	args->req.id = cpu_to_be16(cmd);

	args->req.lpl_len = lpl_len;

	if (lpl) {

	if (lpl)

		memcpy(args->req.payload, lpl, args->req.lpl_len);

		args->read_write_len_ext =

			ethtool_cmis_get_max_lpl_size(read_write_len_ext);

	}

	if (epl) {

		args->req.epl_len = cpu_to_be16(epl_len);

		args->req.epl = epl;

		args->read_write_len_ext =

			ethtool_cmis_get_max_epl_size(read_write_len_ext);

	}



	args->max_duration = max_duration;

	args->read_write_len_ext =

		ethtool_cmis_get_max_lpl_size(read_write_len_ext);

	args->msleep_pre_rpl = msleep_pre_rpl;

	args->rpl_exp_len = rpl_exp_len;

	args->flags = flags;