Re: [PATCH v2 0/8] Introduce fwctl subystem

Jakub Kicinski
2024-06-24T23:18:04Z

On Mon, 24 Jun 2024 19:47:24 -0300 Jason Gunthorpe wrote:
> fwctl is a new subsystem intended to bring some common rules and order to
> the growing pattern of exposing a secure FW interface directly to
> userspace. Unlike existing places like RDMA/DRM/VFIO/uacce that are
> exposing a device for datapath operations fwctl is focused on debugging,
> configuration and provisioning of the device. It will not have the
> necessary features like interrupt delivery to support a datapath.
>
> This concept is similar to the long standing practice in the "HW" RAID
> space of having a device specific misc device to manager the RAID
> controller FW. fwctl generalizes this notion of a companion debug and
> management interface that goes along with a dataplane implemented in an
> appropriate subsystem.
>
> The need for this has reached a critical point as many users are moving to
> run lockdown enabled kernels. Several existing devices have had long
> standing tooling for management that relied on /sys/../resource0 or PCI
> config space access which is not permitted in lockdown. A major point of
> fwctl is to define and document the rules that a device must follow to
> expose a lockdown compatible RPC.
>
> Based on some discussion fwctl splits the RPCs into four categories
>
> FWCTL_RPC_CONFIGURATION
> FWCTL_RPC_DEBUG_READ_ONLY
> FWCTL_RPC_DEBUG_WRITE
> FWCTL_RPC_DEBUG_WRITE_FULL

Nacked-by: Jakub Kicinski <kuba@kernel.org>