net: enetc: deny offload of tc-based TSN features on VF interfaces

TSN features on the ENETC (taprio, cbs, gate, police) are configured
through a mix of command BD ring messages and port registers:
enetc_port_rd(), enetc_port_wr().

Port registers are a region of the ENETC memory map which are only
accessible from the PCIe Physical Function. They are not accessible from
the Virtual Functions.

Moreover, attempting to access these registers crashes the kernel:

$ echo 1 > /sys/bus/pci/devices/0000\:00\:00.0/sriov_numvfs
pci 0000:00:01.0: [1957:ef00] type 00 class 0x020001
fsl_enetc_vf 0000:00:01.0: Adding to iommu group 15
fsl_enetc_vf 0000:00:01.0: enabling device (0000 -> 0002)
fsl_enetc_vf 0000:00:01.0 eno0vf0: renamed from eth0
$ tc qdisc replace dev eno0vf0 root taprio num_tc 8 map 0 1 2 3 4 5 6 7 \
	queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 base-time 0 \
	sched-entry S 0x7f 900000 sched-entry S 0x80 100000 flags 0x2
Unable to handle kernel paging request at virtual address ffff800009551a08
Internal error: Oops: 96000007 [#1] PREEMPT SMP
pc : enetc_setup_tc_taprio+0x170/0x47c
lr : enetc_setup_tc_taprio+0x16c/0x47c
Call trace:
 enetc_setup_tc_taprio+0x170/0x47c
 enetc_setup_tc+0x38/0x2dc
 taprio_change+0x43c/0x970
 taprio_init+0x188/0x1e0
 qdisc_create+0x114/0x470
 tc_modify_qdisc+0x1fc/0x6c0
 rtnetlink_rcv_msg+0x12c/0x390

Split enetc_setup_tc() into separate functions for the PF and for the
VF drivers. Also remove enetc_qos.o from being included into
enetc-vf.ko, since it serves absolutely no purpose there.

Fixes: 34c6adf ("enetc: Configure the Time-Aware Scheduler via tc-taprio offload")
Signed-off-by: Vladimir Oltean <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

drivers/net/ethernet/freescale/enetc/Makefile

@@ -9,7 +9,6 @@ fsl-enetc-$(CONFIG_FSL_ENETC_QOS) += enetc_qos.o
 
 obj-$(CONFIG_FSL_ENETC_VF) += fsl-enetc-vf.o
 fsl-enetc-vf-y := enetc_vf.o $(common-objs)
-fsl-enetc-vf-$(CONFIG_FSL_ENETC_QOS) += enetc_qos.o
 
 obj-$(CONFIG_FSL_ENETC_IERB) += fsl-enetc-ierb.o
 fsl-enetc-ierb-y := enetc_ierb.o

drivers/net/ethernet/freescale/enetc/enetc.c

@@ -2432,7 +2432,7 @@ int enetc_close(struct net_device *ndev)
 	return 0;
 }
 
-static int enetc_setup_tc_mqprio(struct net_device *ndev, void *type_data)
+int enetc_setup_tc_mqprio(struct net_device *ndev, void *type_data)
 {
 	struct enetc_ndev_priv *priv = netdev_priv(ndev);
 	struct tc_mqprio_qopt *mqprio = type_data;
@@ -2486,25 +2486,6 @@ static int enetc_setup_tc_mqprio(struct net_device *ndev, void *type_data)
 	return 0;
 }
 
-int enetc_setup_tc(struct net_device *ndev, enum tc_setup_type type,
-		   void *type_data)
-{
-	switch (type) {
-	case TC_SETUP_QDISC_MQPRIO:
-		return enetc_setup_tc_mqprio(ndev, type_data);
-	case TC_SETUP_QDISC_TAPRIO:
-		return enetc_setup_tc_taprio(ndev, type_data);
-	case TC_SETUP_QDISC_CBS:
-		return enetc_setup_tc_cbs(ndev, type_data);
-	case TC_SETUP_QDISC_ETF:
-		return enetc_setup_tc_txtime(ndev, type_data);
-	case TC_SETUP_BLOCK:
-		return enetc_setup_tc_psfp(ndev, type_data);
-	default:
-		return -EOPNOTSUPP;
-	}
-}
-
 static int enetc_setup_xdp_prog(struct net_device *dev, struct bpf_prog *prog,
 				struct netlink_ext_ack *extack)
 {

drivers/net/ethernet/freescale/enetc/enetc.h

@@ -395,8 +395,7 @@ netdev_tx_t enetc_xmit(struct sk_buff *skb, struct net_device *ndev);
 struct net_device_stats *enetc_get_stats(struct net_device *ndev);
 void enetc_set_features(struct net_device *ndev, netdev_features_t features);
 int enetc_ioctl(struct net_device *ndev, struct ifreq *rq, int cmd);
-int enetc_setup_tc(struct net_device *ndev, enum tc_setup_type type,
-		   void *type_data);
+int enetc_setup_tc_mqprio(struct net_device *ndev, void *type_data);
 int enetc_setup_bpf(struct net_device *dev, struct netdev_bpf *xdp);
 int enetc_xdp_xmit(struct net_device *ndev, int num_frames,
 		   struct xdp_frame **frames, u32 flags);

drivers/net/ethernet/freescale/enetc/enetc_pf.c

@@ -734,6 +734,25 @@ static int enetc_pf_set_features(struct net_device *ndev,
 	return 0;
 }
 
+static int enetc_pf_setup_tc(struct net_device *ndev, enum tc_setup_type type,
+			     void *type_data)
+{
+	switch (type) {
+	case TC_SETUP_QDISC_MQPRIO:
+		return enetc_setup_tc_mqprio(ndev, type_data);
+	case TC_SETUP_QDISC_TAPRIO:
+		return enetc_setup_tc_taprio(ndev, type_data);
+	case TC_SETUP_QDISC_CBS:
+		return enetc_setup_tc_cbs(ndev, type_data);
+	case TC_SETUP_QDISC_ETF:
+		return enetc_setup_tc_txtime(ndev, type_data);
+	case TC_SETUP_BLOCK:
+		return enetc_setup_tc_psfp(ndev, type_data);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
 static const struct net_device_ops enetc_ndev_ops = {
 	.ndo_open		= enetc_open,
 	.ndo_stop		= enetc_close,
@@ -748,7 +767,7 @@ static const struct net_device_ops enetc_ndev_ops = {
 	.ndo_set_vf_spoofchk	= enetc_pf_set_vf_spoofchk,
 	.ndo_set_features	= enetc_pf_set_features,
 	.ndo_eth_ioctl		= enetc_ioctl,
-	.ndo_setup_tc		= enetc_setup_tc,
+	.ndo_setup_tc		= enetc_pf_setup_tc,
 	.ndo_bpf		= enetc_setup_bpf,
 	.ndo_xdp_xmit		= enetc_xdp_xmit,
 };

drivers/net/ethernet/freescale/enetc/enetc_vf.c

@@ -93,6 +93,17 @@ static int enetc_vf_set_features(struct net_device *ndev,
 	return 0;
 }
 
+static int enetc_vf_setup_tc(struct net_device *ndev, enum tc_setup_type type,
+			     void *type_data)
+{
+	switch (type) {
+	case TC_SETUP_QDISC_MQPRIO:
+		return enetc_setup_tc_mqprio(ndev, type_data);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
 /* Probing/ Init */
 static const struct net_device_ops enetc_ndev_ops = {
 	.ndo_open		= enetc_open,
@@ -102,7 +113,7 @@ static const struct net_device_ops enetc_ndev_ops = {
 	.ndo_set_mac_address	= enetc_vf_set_mac_addr,
 	.ndo_set_features	= enetc_vf_set_features,
 	.ndo_eth_ioctl		= enetc_ioctl,
-	.ndo_setup_tc		= enetc_setup_tc,
+	.ndo_setup_tc		= enetc_vf_setup_tc,
 };
 
 static void enetc_vf_netdev_setup(struct enetc_si *si, struct net_device *ndev,