pds_fwctl: initial driver framework

Initial files for adding a new fwctl driver for the AMD/Pensando PDS
devices. This sets up a simple auxiliary_bus driver that registers
with fwctl subsystem. It

pds_fwctl: initial driver framework

Initial files for adding a new fwctl driver for the AMD/Pensando PDS
devices. This sets up a simple auxiliary_bus driver that registers
with fwctl subsystem. It expects that a pds_core device has set up
the auxiliary_device pds_core.fwctl

Link: https://patch.msgid.link/r/[email protected]
Reviewed-by: Leon Romanovsky <[email protected]>
Reviewed-by: Dave Jiang <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>
Signed-off-by: Shannon Nelson <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

show more ...

fwctl/mlx5: Support for communicating with mlx5 fw

mlx5 FW has a built in security context called UID. Each UID has a set of
permissions controlled by the kernel when it is created and every command

fwctl/mlx5: Support for communicating with mlx5 fw

mlx5 FW has a built in security context called UID. Each UID has a set of
permissions controlled by the kernel when it is created and every command
is tagged by the kernel with a particular UID. In general commands cannot
reach objects outside of their UID and commands cannot exceed their UID's
permissions. These restrictions are enforced by FW.

This mechanism has long been used in RDMA for the devx interface where
RDMA will sent commands directly to the FW and the UID limitations
restrict those commands to a ib_device/verbs security domain. For instance
commands that would effect other VFs, or global device resources. The
model is suitable for unprivileged userspace to operate the RDMA
functionality.

The UID has been extended with a "tools resources" permission which allows
additional commands and sub-commands that are intended to match with the
scope limitations set in FWCTL. This is an alternative design to the
"command intent log" where the FW does the enforcement rather than having
the FW report the enforcement the kernel should do.

Consistent with the fwctl definitions the "tools resources" security
context is limited to the FWCTL_RPC_CONFIGURATION,
FWCTL_RPC_DEBUG_READ_ONLY, FWCTL_RPC_DEBUG_WRITE, and
FWCTL_RPC_DEBUG_WRITE_FULL security scopes.

Like RDMA devx, each opened fwctl file descriptor will get a unique UID
associated with each file descriptor.

The fwctl driver is kept simple and we reject commands that can create
objects as the UID mechanism relies on the kernel to track and destroy
objects prior to detroying the UID. Filtering into fwctl sub scopes is
done inside the driver with a switch statement. This substantially limits
what is possible to primarily query functions ad a few limited set
operations.

mlx5 already has a robust infrastructure for delivering RPC messages to
fw. Trivially connect fwctl's RPC mechanism to mlx5_cmd_do(). Enforce the
User Context ID in every RPC header accepted from the FD so the FW knows
the security context of the issuing ID.

Link: https://patch.msgid.link/r/[email protected]
Reviewed-by: Jonathan Cameron <[email protected]>
Signed-off-by: Saeed Mahameed <[email protected]>
Reviewed-by: Leon Romanovsky <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

show more ...

fwctl: Add basic structure for a class subsystem with a cdev

Create the class, character device and functions for a fwctl driver to
un/register to the subsystem.

A typical fwctl driver has a sysfs

fwctl: Add basic structure for a class subsystem with a cdev

Create the class, character device and functions for a fwctl driver to
un/register to the subsystem.

A typical fwctl driver has a sysfs presence like:

$ ls -l /dev/fwctl/fwctl0
crw------- 1 root root 250, 0 Apr 25 19:16 /dev/fwctl/fwctl0

$ ls /sys/class/fwctl/fwctl0
dev device power subsystem uevent

$ ls /sys/class/fwctl/fwctl0/device/infiniband/
ibp0s10f0

$ ls /sys/class/infiniband/ibp0s10f0/device/fwctl/
fwctl0/

$ ls /sys/devices/pci0000:00/0000:00:0a.0/fwctl/fwctl0
dev device power subsystem uevent

Which allows userspace to link all the multi-subsystem driver components
together and learn the subsystem specific names for the device's
components.

Link: https://patch.msgid.link/r/[email protected]
Reviewed-by: Jonathan Cameron <[email protected]>
Reviewed-by: Dan Williams <[email protected]>
Reviewed-by: Dave Jiang <[email protected]>
Reviewed-by: Shannon Nelson <[email protected]>
Tested-by: Dave Jiang <[email protected]>
Tested-by: Shannon Nelson <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

show more ...