[PATCH 3/4] sfc: explain that "attached" VFs only refer to Xen

From: Íñigo Huguet
Date: Mon Jun 21 2021 - 11:33:21 EST


During SRIOV disabling it is checked wether any VF is currently attached
to a guest, using pci_vfs_assigned function. However, this check only
works with VFs attached with Xen, not with vfio/KVM. Added comments
clarifying this point.

Also, replaced manual check of PCI_DEV_FLAGS_ASSIGNED flag and used the
helper function pci_is_dev_assigned instead.

Signed-off-by: Íñigo Huguet <ihuguet@xxxxxxxxxx>
---
drivers/net/ethernet/sfc/ef10.c | 3 ++-
drivers/net/ethernet/sfc/ef10_sriov.c | 7 ++++---
2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index c3f35da1b82a..bea961013f7c 100644
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -1070,7 +1070,8 @@ static int efx_ef10_probe_vf(struct efx_nic *efx)

/* If the parent PF has no VF data structure, it doesn't know about this
* VF so fail probe. The VF needs to be re-created. This can happen
- * if the PF driver is unloaded while the VF is assigned to a guest.
+ * if the PF driver was unloaded while any VF was assigned to a guest
+ * (using Xen, only).
*/
pci_dev_pf = efx->pci_dev->physfn;
if (pci_dev_pf) {
diff --git a/drivers/net/ethernet/sfc/ef10_sriov.c b/drivers/net/ethernet/sfc/ef10_sriov.c
index 84041cd587d7..f8f8fbe51ef8 100644
--- a/drivers/net/ethernet/sfc/ef10_sriov.c
+++ b/drivers/net/ethernet/sfc/ef10_sriov.c
@@ -122,8 +122,7 @@ static void efx_ef10_sriov_free_vf_vports(struct efx_nic *efx)
struct ef10_vf *vf = nic_data->vf + i;

/* If VF is assigned, do not free the vport */
- if (vf->pci_dev &&
- vf->pci_dev->dev_flags & PCI_DEV_FLAGS_ASSIGNED)
+ if (vf->pci_dev && pci_is_dev_assigned(vf->pci_dev))
continue;

if (vf->vport_assigned) {
@@ -449,7 +448,9 @@ void efx_ef10_sriov_fini(struct efx_nic *efx)
int rc;

if (!nic_data->vf) {
- /* Remove any un-assigned orphaned VFs */
+ /* Remove any un-assigned orphaned VFs. This can happen if the PF driver
+ * was unloaded while any VF was assigned to a guest (using Xen, only).
+ */
if (pci_num_vf(efx->pci_dev) && !pci_vfs_assigned(efx->pci_dev))
pci_disable_sriov(efx->pci_dev);
return;
--
2.31.1