[PATCH v3 net-next 11/15] net: enetc: restore VF MAC promiscuous mode after FLR for ENETC v4

[wei.fang@oss.nxp.com]

From: Wei Fang <wei.fang@nxp.com>

On ENETC v4, when VF performs a PCI FLR, it resets PSIPMMR[SIn_MAC_UP]
and PSIPMMR[SIn_MAC_MP] bits, which control the unicast and multicast
promiscuous mode for the corresponding SI. The reset (default) value of
these bits enables promiscuous mode, meaning that after a VF FLR, the
SI is left in promiscuous mode regardless of the configuration set by
the PF driver prior to the reset.

This is a potential security vulnerability: a malicious VM could
deliberately trigger a VF FLR to force promiscuous mode on its SI,
allowing it to capture network traffic not destined for that VF.

To mitigate this, make the following changes:

- Add ENETC_VF_FLAG_UC_PROMISC and ENETC_VF_FLAG_MC_PROMISC to
  enetc_vf_flags to track the PF-managed promiscuous mode state for each
  VF.

- Update enetc_msg_set_vf_mac_promisc_mode() to keep these flags in sync
  whenever a VF requests a promiscuous mode change via messaging.

- Update enetc_pf_set_vf_trust() to clear both promisc flags when a VF
  is untrusted, so that a subsequent FLR cannot restore promiscuous mode
  that the PF has already revoked.

- Add a vf_flr_handler callback to enetc_pf_ops. The ENETC v4
  implementation re-applies the tracked UC/MC promiscuous mode settings
  to the hardware after each FLR, ensuring the hardware state matches
  the PF-managed policy rather than the insecure reset default.

- Add enetc_vf_flr_handler() in enetc_msg.c to detect FLR events via the
  PSIIDR register and dispatch to the vf_flr_handler callback. Invoke it
  at the start of enetc_msg_task() before processing VF messages.

- Enable FLR interrupts in PSIIER only when a vf_flr_handler callback is
  registered, keeping ENETC v1 behavior unchanged.

Signed-off-by: Wei Fang <wei.fang@nxp.com>
---
 .../net/ethernet/freescale/enetc/enetc4_pf.c  | 20 ++++++++
 .../net/ethernet/freescale/enetc/enetc_hw.h   | 12 +++++
 .../net/ethernet/freescale/enetc/enetc_msg.c  | 50 +++++++++++++++++++
 .../net/ethernet/freescale/enetc/enetc_pf.h   |  3 ++
 .../freescale/enetc/enetc_pf_common.c         |  4 +-
 5 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/enetc/enetc4_pf.c b/drivers/net/ethernet/freescale/enetc/enetc4_pf.c
index a4ffe1100bd7..c421c0e7355b 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc4_pf.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc4_pf.c
@@ -212,9 +212,29 @@ static void enetc4_pf_set_mac_filter(struct enetc_pf *pf, int type,
 		enetc4_pf_set_mc_hash_filter(pf, mc);
 }
 
+static void enetc4_pf_vf_flr_handler(struct enetc_pf *pf, int vf_id)
+{
+	struct enetc_vf_state *vf_state;
+	bool uc_promisc, mc_promisc;
+
+	vf_state = &pf->vf_state[vf_id];
+	mutex_lock(&vf_state->lock);
+
+	uc_promisc = !!(vf_state->flags & ENETC_VF_FLAG_UC_PROMISC);
+	mc_promisc = !!(vf_state->flags & ENETC_VF_FLAG_MC_PROMISC);
+
+	mutex_lock(&pf->msg_lock);
+	enetc_set_si_uc_promisc(pf->si, vf_id + 1, uc_promisc);
+	enetc_set_si_mc_promisc(pf->si, vf_id + 1, mc_promisc);
+	mutex_unlock(&pf->msg_lock);
+
+	mutex_unlock(&vf_state->lock);
+}
+
 static const struct enetc_pf_ops enetc4_pf_ops = {
 	.set_si_primary_mac = enetc4_pf_set_si_primary_mac,
 	.get_si_primary_mac = enetc4_pf_get_si_primary_mac,
+	.vf_flr_handler = enetc4_pf_vf_flr_handler,
 };
 
 static int enetc4_pf_struct_init(struct enetc_si *si)
diff --git a/drivers/net/ethernet/freescale/enetc/enetc_hw.h b/drivers/net/ethernet/freescale/enetc/enetc_hw.h
index f97602714118..c18ad8b9b071 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_hw.h
+++ b/drivers/net/ethernet/freescale/enetc/enetc_hw.h
@@ -110,6 +110,18 @@ static inline u32 enetc_vsi_set_msize(u32 size)
 
 #define ENETC_PSIIER	0xa00
 #define ENETC_PSIIDR	0xa08
+
+/* VF FLR interrupt mask, n is the active number of VFs.
+ * It is available for ENETC_PSIIER and ENETC_PSIIDR registers.
+ */
+#define ENETC_VFFLR_MASK(n)	\
+	({ typeof(n) _n = (n); (_n) ? GENMASK(16 + (_n), 17) : 0; })
+
+/* VF FLR interrupt bit, n is VF index. It is available
+ * for ENETC_PSIIER and ENETC_PSIIDR registers.
+ */
+#define ENETC_VFFLR_BIT(n)	BIT(17 + (n))
+
 #define ENETC_SITXIDR	0xa18
 #define ENETC_SIRXIDR	0xa28
 #define ENETC_SIMSIVR	0xa30
diff --git a/drivers/net/ethernet/freescale/enetc/enetc_msg.c b/drivers/net/ethernet/freescale/enetc/enetc_msg.c
index 4aabeb23a386..55c23d4a73a8 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_msg.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_msg.c
@@ -27,6 +27,9 @@ static void enetc_enable_psiier_interrupts(struct enetc_pf *pf)
 	u32 psiier = ENETC_PSIMR_MASK(pf->num_vfs);
 	struct enetc_hw *hw = &pf->si->hw;
 
+	if (pf->ops->vf_flr_handler)
+		psiier |= ENETC_VFFLR_MASK(pf->num_vfs);
+
 	enetc_wr(hw, ENETC_PSIIER, psiier);
 }
 
@@ -208,6 +211,20 @@ static u16 enetc_msg_set_vf_mac_promisc_mode(struct enetc_pf *pf, int vf_id,
 		goto vf_state_unlock;
 	}
 
+	if (type & ENETC_MAC_FILTER_TYPE_UC) {
+		if (promisc)
+			vf_state->flags |= ENETC_VF_FLAG_UC_PROMISC;
+		else
+			vf_state->flags &= ~ENETC_VF_FLAG_UC_PROMISC;
+	}
+
+	if (type & ENETC_MAC_FILTER_TYPE_MC) {
+		if (promisc)
+			vf_state->flags |= ENETC_VF_FLAG_MC_PROMISC;
+		else
+			vf_state->flags &= ~ENETC_VF_FLAG_MC_PROMISC;
+	}
+
 	mutex_lock(&pf->msg_lock);
 
 	if (type & ENETC_MAC_FILTER_TYPE_UC)
@@ -594,6 +611,29 @@ static void enetc_msg_handle_rxmsg(struct enetc_pf *pf, int vf_id,
 	kfree(msg);
 }
 
+static void enetc_vf_flr_handler(struct enetc_pf *pf)
+{
+	u32 flr_mask = ENETC_VFFLR_MASK(pf->num_vfs);
+	struct enetc_hw *hw = &pf->si->hw;
+	u32 flr_status;
+
+	if (!pf->ops->vf_flr_handler)
+		return;
+
+	flr_status = enetc_rd(hw, ENETC_PSIIDR) & flr_mask;
+	if (!flr_status)
+		return;
+
+	for (int i = 0; i < pf->num_vfs; i++) {
+		if (!(ENETC_VFFLR_BIT(i) & flr_status))
+			continue;
+
+		/* Clear FLR interrupt status, W1C */
+		enetc_wr(hw, ENETC_PSIIDR, ENETC_VFFLR_BIT(i));
+		pf->ops->vf_flr_handler(pf, i);
+	}
+}
+
 static void enetc_msg_task(struct work_struct *work)
 {
 	struct enetc_si *si = container_of(work, struct enetc_si, msg_task);
@@ -602,6 +642,8 @@ static void enetc_msg_task(struct work_struct *work)
 	u32 mr_status, mr_mask;
 	int i;
 
+	enetc_vf_flr_handler(pf);
+
 	mr_mask = ENETC_PSIMR_MASK(pf->num_vfs);
 	mr_status = (enetc_rd(hw, ENETC_PSIMSGRR) & mr_mask) |
 		    (enetc_rd(hw, ENETC_PSIIDR) & mr_mask);
@@ -728,6 +770,14 @@ static void enetc_msg_clear_vf_config(struct enetc_pf *pf, int vf_id)
 
 	mutex_lock(&vf_state->lock);
 
+	/* VF may set these flags by mailbox messages, so need to clear these
+	 * flags when enetc_msg_psi_free() is called. PF-set flags (TRUSTED,
+	 * PF_SET_MAC) are not cleared, because these flags are unrelated to
+	 * whether SR-IOV is enabled or disabled.
+	 */
+	vf_state->flags &= ~(ENETC_VF_FLAG_UC_PROMISC |
+			     ENETC_VF_FLAG_MC_PROMISC);
+
 	mutex_lock(&pf->msg_lock);
 	enetc_set_si_uc_promisc(si, si_id, false);
 	enetc_set_si_mc_promisc(si, si_id, false);
diff --git a/drivers/net/ethernet/freescale/enetc/enetc_pf.h b/drivers/net/ethernet/freescale/enetc/enetc_pf.h
index 12e67f611f77..6bf4105ee0e3 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_pf.h
+++ b/drivers/net/ethernet/freescale/enetc/enetc_pf.h
@@ -11,6 +11,8 @@
 enum enetc_vf_flags {
 	ENETC_VF_FLAG_PF_SET_MAC	= BIT(0),
 	ENETC_VF_FLAG_TRUSTED		= BIT(1),
+	ENETC_VF_FLAG_UC_PROMISC	= BIT(2),
+	ENETC_VF_FLAG_MC_PROMISC	= BIT(3),
 };
 
 struct enetc_vf_state {
@@ -32,6 +34,7 @@ struct enetc_pf_ops {
 	struct phylink_pcs *(*create_pcs)(struct enetc_pf *pf, struct mii_bus *bus);
 	void (*destroy_pcs)(struct phylink_pcs *pcs);
 	int (*enable_psfp)(struct enetc_ndev_priv *priv);
+	void (*vf_flr_handler)(struct enetc_pf *pf, int vf_id);
 };
 
 struct enetc_pf {
diff --git a/drivers/net/ethernet/freescale/enetc/enetc_pf_common.c b/drivers/net/ethernet/freescale/enetc/enetc_pf_common.c
index 8007dce90195..10134d7a1f70 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_pf_common.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_pf_common.c
@@ -625,7 +625,9 @@ int enetc_pf_set_vf_trust(struct net_device *ndev, int vf, bool setting)
 	} else {
 		u64 hash;
 
-		vf_state->flags &= ~ENETC_VF_FLAG_TRUSTED;
+		vf_state->flags &= ~(ENETC_VF_FLAG_TRUSTED |
+				     ENETC_VF_FLAG_UC_PROMISC |
+				     ENETC_VF_FLAG_MC_PROMISC);
 
 		/* For ENETC v1, we only support setting the VF's MAC address
 		 * via VSI-to-PSI messages. Unicast and multicast promiscuous
-- 
2.34.1