drm/xe: Enable SR-IOV for PTL

We should now have sufficient changes in the driver to run it on
PTL platforms in the SR-IOV Physical Function (PF) mode, that would
allow us to enable SR-IOV Virtual Functions (VFs), and successfully
probe our driver in the VF mode on enabled VF devices.

To unblock SR-IOV PF mode you need to load xe with modparam:

 xe.max_vfs=7

Then to enable VFs it is sufficient to use:

 $ echo 7 > /sys/bus/pci/devices/0000:00:02.0/sriov_numvfs

Note that in default auto-provisioning all VFs are allocated with
some amount of shared resources (like unlimited GPU execution and
preemption times, fair GGTT space, fair GuC context IDs range, ...)

However with CONFIG_DEBUG_FS enabled it is possible to tweak most
of the SR-IOV configuration parameters using attributes like:

 /sys/kernel/debug/dri/0000:00:02.0/gt0/
 ├── pf
 │   ├── contexts_spare
 │   ├── doorbells_spare
 │   ├── exec_quantum_ms
 │   ├── ggtt_spare
 │   ├── preempt_timeout_us
 │   ├── sched_priority
 │   └── ...
 ├── vf1
 │   ├── contexts_quota
 │   ├── doorbells_quota
 │   ├── exec_quantum_ms
 │   ├── ggtt_quota
 │   ├── preempt_timeout_us
 │   ├── sched_priority
 │   └── ...
 ├── vf2
 │   └── ...
 :

Signed-off-by: Michal Wajdeczko <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Lucas De Marchi <[email protected]>
Cc: Thomas Hellstrom <[email protected]>
Acked-by: Rodrigo Vivi <[email protected]>
Reviewed-by: Jakub Kolakowski <[email protected]>
Tested-by: Marcin Bernatowicz <[email protected]>
Reviewed-by: Marcin Bernatowicz <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: mwajdecz

drivers/gpu/drm/xe/xe_pci.c

@@ -363,6 +363,7 @@ static const struct xe_device_desc ptl_desc = {
 	PLATFORM(PANTHERLAKE),
 	.dma_mask_size = 46,
 	.has_display = true,
+	.has_sriov = true,
 	.require_force_probe = true,
 };