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
Instead of trying very hard to find the largest fair number of GuC
context IDs that could be allocated for VFs on the current GT, pick
some smaller rounded down to power-of-two value that is more likely
to be provisioned in the same manner by the other PF instance:
num VFs | num contexts
--------+-------------
63..32 | 1024
31..16 | 2048
15..8 | 4096
7..4 | 8192
3..2 | 16384
1 | 32768 (regular PF)
1 | 64512 (admin only PF)
Add also helper function to determine if the PF is admin-only,
and for now use .probe_display flag for that.
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Link: https://patch.msgid.link/20251105183253.863-2-michal.wajdeczko@intel.com
