Commit 75fe5f34 authored by Michal Wajdeczko's avatar Michal Wajdeczko
Browse files

drm/xe/pf: Don't advertise support to enable VFs if not ready 



Even if we have not enabled SR-IOV support using the platform
specific has_sriov flag, the hardware may still report SR-IOV
capability and the PCI layer may wrongly advertise driver support
to enable VFs.  Explicitly reset the number of supported VFs to
zero to avoid confusion.

Applications may read the /sys/bus/pci/devices/.../sriov_totalvfs
prior to enabling VFs using the sriov_numvfs to check if such an
operation is possible.

Signed-off-by: default avatarMichal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: default avatarPiotr Piórkowski <piotr.piorkowski@intel.com>
Acked-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240507165757.2835-1-michal.wajdeczko@intel.com
parent c8ff26b8

drivers/gpu/drm/xe/xe_sriov.c

+11 −0
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ static bool test_is_vf(struct xe_device *xe) 
 */

void xe_sriov_probe_early(struct xe_device *xe)

{

	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);

	enum xe_sriov_mode mode = XE_SRIOV_MODE_NONE;

	bool has_sriov = xe->info.has_sriov;
@@ -61,6 +62,16 @@ void xe_sriov_probe_early(struct xe_device *xe) 
			mode = XE_SRIOV_MODE_VF;

		else if (xe_sriov_pf_readiness(xe))

			mode = XE_SRIOV_MODE_PF;

	} else if (pci_sriov_get_totalvfs(pdev)) {

		/*

		 * Even if we have not enabled SR-IOV support using the

		 * platform specific has_sriov flag, the hardware may still

		 * report SR-IOV capability and the PCI layer may wrongly

		 * advertise driver support to enable VFs. Explicitly reset

		 * the number of supported VFs to zero to avoid confusion.

		 */

		drm_info(&xe->drm, "Support for SR-IOV is not available\n");

		pci_sriov_set_totalvfs(pdev, 0);

	}



	xe_assert(xe, !xe->sriov.__mode);