ice: restore VF MSI-X state during PCI reset

During a PCI FLR the MSI-X Enable flag in the VF PCI MSI-X capability
register will be cleared. This can lead to issues when a VF is
assigned to a VM because in these cases the VF driver receives no
indication of the PF PCI error/reset and additionally it is incapable
of restoring the cleared flag in the hypervisor configuration space
without fully reinitializing the driver interrupt functionality.

Since the VF driver is unable to easily resolve this condition on its own,
restore the VF MSI-X flag during the PF PCI reset handling.

Signed-off-by: Nick Nunley <nicholas.d.nunley@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_virtchnl_pf.c b/drivers/net/ethernet/intel/ice/ice_virtchnl_pf.c
index 9df5ceb26ab9..7061730f0f37 100644
--- a/drivers/net/ethernet/intel/ice/ice_virtchnl_pf.c
+++ b/drivers/net/ethernet/intel/ice/ice_virtchnl_pf.c
@@ -4071,3 +4071,33 @@ void ice_print_vfs_mdd_events(struct ice_pf *pf)
 		}
 	}
 }
+
+/**
+ * ice_restore_all_vfs_msi_state - restore VF MSI state after PF FLR
+ * @pdev: pointer to a pci_dev structure
+ *
+ * Called when recovering from a PF FLR to restore interrupt capability to
+ * the VFs.
+ */
+void ice_restore_all_vfs_msi_state(struct pci_dev *pdev)
+{
+	struct pci_dev *vfdev;
+	u16 vf_id;
+	int pos;
+
+	if (!pci_num_vf(pdev))
+		return;
+
+	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_SRIOV);
+	if (pos) {
+		pci_read_config_word(pdev, pos + PCI_SRIOV_VF_DID,
+				     &vf_id);
+		vfdev = pci_get_device(pdev->vendor, vf_id, NULL);
+		while (vfdev) {
+			if (vfdev->is_virtfn && vfdev->physfn == pdev)
+				pci_restore_msi_state(vfdev);
+			vfdev = pci_get_device(pdev->vendor, vf_id,
+					       vfdev);
+		}
+	}
+}