ixl(4): Fix SR-IOV panics

The hw and ifp of a vsi will be NULL if such ixl_vsi is allocated
for a VF. When ixl_reconfigure_filters called, it is trying to
access vsi->ifp and hw->mac.addr and therefore is casuing panic.

This commit add checks to determine if vsi is a VF by checking
if vsi->hw is NULL, before adding IXL_VLAN_ANY filter (which
is already in a VF vsi's filter list) and VLAN filters.

(erj's Note: The SR-IOV flows need revisiting; this will help
prevent panics for now)

Reviewed by:	krzysztof.galazka@intel.com, erj@
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D35649

(cherry picked from commit e706512a2b64fa2741144caf056c9fe923b60004)

1 files changed, 8 insertions, 0 deletions

diff --git a/sys/dev/ixl/ixl_pf_main.c b/sys/dev/ixl/ixl_pf_main.c
index 4d75200ea739..61dd4da05030 100644
--- a/sys/dev/ixl/ixl_pf_main.c
+++ b/sys/dev/ixl/ixl_pf_main.c
@@ -1124,6 +1124,14 @@ ixl_reconfigure_filters(struct ixl_vsi *vsi)
 
 	ixl_add_hw_filters(vsi, &tmp, cnt);
 
+	/*
+	 * When the vsi is allocated for the VFs, both vsi->hw and vsi->ifp
+	 * will be NULL. Furthermore, the ftl of such vsi already contains
+	 * IXL_VLAN_ANY filter so we can skip that as well.
+	 */
+	if (hw == NULL)
+		return;
+
 	/* Filter could be removed if MAC address was changed */
 	ixl_add_filter(vsi, hw->mac.addr, IXL_VLAN_ANY);