Some driver components, like eudebug or ccs-mode, can't be used
when VFs are enabled. Add functions to allow those components
to block the PF from enabling VFs for the requested duration.
Introduce trivial counter to allow lockdown or exclusive access
that can be used in the scenarios where we can't follow the strict
owner semantics as required by the rw_semaphore implementation.
Before enabling VFs, the PF will try to arm the "vfs_enabling"
guard for the exclusive access. This will fail if there are
some lockdown requests already initiated by the other components.
For testing purposes, add debugfs file which will call these new
functions from the file's open/close hooks.
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Christoph Manszewski <christoph.manszewski@intel.com>
Reviewed-by: Christoph Manszewski <christoph.manszewski@intel.com>
Link: https://patch.msgid.link/20251109162451.4779-1-michal.wajdeczko@intel.com
Currently we expose debugfs files related to SR-IOV functions
together with other native files, but that approach will not
scale well as we plan to add more attributes and also expose
some of them on the per-tile basis.
Start building separate tree for SR-IOV specific debugfs files
where we can replicate similar files per every SR-IOV function:
/sys/kernel/debug/dri/BDF/
├── sriov
│ ├── pf
│ │ ├── tile0
│ │ │ ├── gt0
│ │ │ ├── gt1
│ │ │ :
│ │ ├── tile1
│ │ :
│ ├── vf1
│ │ ├── tile0
│ │ │ ├── gt0
│ │ │ ├── gt1
│ │ │ :
│ │ :
│ ├── vf2
│ ├── ...
We will populate this new tree in upcoming patches.
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20250928140029.198847-3-michal.wajdeczko@intel.com
