Implement "mdd-auto-reset-vf" priv-flag to handle Tx and Rx MDD events for VFs.
This flag is also used in other network adapters like ICE.

Usage:
- "on"  - The problematic VF will be automatically reset
          if a malformed descriptor is detected.
- "off" - The problematic VF will be disabled.

In cases where a VF sends malformed packets classified as malicious, it can
cause the Tx queue to freeze, rendering it unusable for several minutes. When
an MDD event occurs, this new implementation allows for a graceful VF reset to
quickly restore operational state.

Currently, VF queues are disabled if an MDD event occurs. This patch adds the
ability to reset the VF if a Tx or Rx MDD event occurs. It also includes MDD
event logging throttling to avoid dmesg pollution and unifies the format of
Tx and Rx MDD messages.

Note: Standard message rate limiting functions like dev_info_ratelimited()
do not meet our requirements. Custom rate limiting is implemented,
please see the code for details.

Co-developed-by: Jan Sokolowski <jan.sokolow...@intel.com>
Signed-off-by: Jan Sokolowski <jan.sokolow...@intel.com>
Co-developed-by: Padraig J Connolly <padraig.j.conno...@intel.com>
Signed-off-by: Padraig J Connolly <padraig.j.conno...@intel.com>
Signed-off-by: Aleksandr Loktionov <aleksandr.loktio...@intel.com>
---
v4->v5 + documentation - 2nd clear_bit(__I40E_MDD_EVENT_PENDING) * rate limit
v3->v4 refactor two helper functions into one
v2->v3 fix compilation issue
v1->v2 fix compilation issue
---
 .../device_drivers/ethernet/intel/i40e.rst    |  12 ++
 drivers/net/ethernet/intel/i40e/i40e.h        |   4 +-
 .../net/ethernet/intel/i40e/i40e_debugfs.c    |   2 +-
 .../net/ethernet/intel/i40e/i40e_ethtool.c    |   2 +
 drivers/net/ethernet/intel/i40e/i40e_main.c   | 107 +++++++++++++++---
 .../ethernet/intel/i40e/i40e_virtchnl_pf.c    |   2 +-
 .../ethernet/intel/i40e/i40e_virtchnl_pf.h    |  11 +-
 7 files changed, 123 insertions(+), 17 deletions(-)

diff --git a/Documentation/networking/device_drivers/ethernet/intel/i40e.rst 
b/Documentation/networking/device_drivers/ethernet/intel/i40e.rst
index 4fbaa1a..53d9d58 100644
--- a/Documentation/networking/device_drivers/ethernet/intel/i40e.rst
+++ b/Documentation/networking/device_drivers/ethernet/intel/i40e.rst
@@ -299,6 +299,18 @@ Use ethtool to view and set link-down-on-close, as 
follows::
   ethtool --show-priv-flags ethX
   ethtool --set-priv-flags ethX link-down-on-close [on|off]
 
+Setting the mdd-auto-reset-vf Private Flag
+------------------------------------------
+
+When the mdd-auto-reset-vf private flag is set to "on", the problematic VF will
+be automatically reset if a malformed descriptor is detected. If the flag is
+set to "off", the problematic VF will be disabled.
+
+Use ethtool to view and set mdd-auto-reset-vf, as follows::
+
+  ethtool --show-priv-flags ethX
+  ethtool --set-priv-flags ethX mdd-auto-reset-vf [on|off]
+
 Viewing Link Messages
 ---------------------
 Link messages will not be displayed to the console if the distribution is
diff --git a/drivers/net/ethernet/intel/i40e/i40e.h 
b/drivers/net/ethernet/intel/i40e/i40e.h
index d546567..ee5d8d6 100644
--- a/drivers/net/ethernet/intel/i40e/i40e.h
+++ b/drivers/net/ethernet/intel/i40e/i40e.h
@@ -87,6 +87,7 @@ enum i40e_state {
        __I40E_SERVICE_SCHED,
        __I40E_ADMINQ_EVENT_PENDING,
        __I40E_MDD_EVENT_PENDING,
+       __I40E_MDD_VF_PRINT_PENDING,
        __I40E_VFLR_EVENT_PENDING,
        __I40E_RESET_RECOVERY_PENDING,
        __I40E_TIMEOUT_RECOVERY_PENDING,
@@ -190,6 +191,7 @@ enum i40e_pf_flags {
         */
        I40E_FLAG_TOTAL_PORT_SHUTDOWN_ENA,
        I40E_FLAG_VF_VLAN_PRUNING_ENA,
+       I40E_FLAG_MDD_AUTO_RESET_VF,
        I40E_PF_FLAGS_NBITS,            /* must be last */
 };
 
@@ -571,7 +573,7 @@ struct i40e_pf {
        int num_alloc_vfs;      /* actual number of VFs allocated */
        u32 vf_aq_requests;
        u32 arq_overflows;      /* Not fatal, possibly indicative of problems */
-
+       struct ratelimit_state mdd_message_rate_limit;
        /* DCBx/DCBNL capability for PF that indicates
         * whether DCBx is managed by firmware or host
         * based agent (LLDPAD). Also, indicates what
diff --git a/drivers/net/ethernet/intel/i40e/i40e_debugfs.c 
b/drivers/net/ethernet/intel/i40e/i40e_debugfs.c
index abf624d..6a697bf 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_debugfs.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_debugfs.c
@@ -721,7 +721,7 @@ static void i40e_dbg_dump_vf(struct i40e_pf *pf, int vf_id)
                dev_info(&pf->pdev->dev, "vf %2d: VSI id=%d, seid=%d, qps=%d\n",
                         vf_id, vf->lan_vsi_id, vsi->seid, vf->num_queue_pairs);
                dev_info(&pf->pdev->dev, "       num MDD=%lld\n",
-                        vf->num_mdd_events);
+                        vf->mdd_tx_events.count + vf->mdd_rx_events.count);
        } else {
                dev_info(&pf->pdev->dev, "invalid VF id %d\n", vf_id);
        }
diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c 
b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
index 1d0d2e5..d146575 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
@@ -459,6 +459,8 @@ static const struct i40e_priv_flags 
i40e_gstrings_priv_flags[] = {
        I40E_PRIV_FLAG("base-r-fec", I40E_FLAG_BASE_R_FEC, 0),
        I40E_PRIV_FLAG("vf-vlan-pruning",
                       I40E_FLAG_VF_VLAN_PRUNING_ENA, 0),
+       I40E_PRIV_FLAG("mdd-auto-reset-vf",
+                      I40E_FLAG_MDD_AUTO_RESET_VF, 0),
 };
 
 #define I40E_PRIV_FLAGS_STR_LEN ARRAY_SIZE(i40e_gstrings_priv_flags)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c 
b/drivers/net/ethernet/intel/i40e/i40e_main.c
index cbcfada..b1f7316 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -11189,22 +11189,88 @@ static void i40e_handle_reset_warning(struct i40e_pf 
*pf, bool lock_acquired)
        i40e_reset_and_rebuild(pf, false, lock_acquired);
 }
 
+/**
+ * i40e_print_vf_mdd_event - print VF Tx/Rx malicious driver detect event
+ * @pf: board private structure
+ * @vf: pointer to the VF structure
+ * @is_tx: true - for Tx event, false - for  Rx
+ */
+static void i40e_print_vf_mdd_event(struct i40e_pf *pf, struct i40e_vf *vf,
+                                      bool is_tx)
+{
+       dev_err(&pf->pdev->dev, is_tx ?
+               "%lld Tx Malicious Driver Detection events detected on PF %d VF 
%d MAC %pm. mdd-auto-reset-vfs=%s\n" :
+               "%lld Rx Malicious Driver Detection events detected on PF %d VF 
%d MAC %pm. mdd-auto-reset-vfs=%s\n",
+               is_tx ? vf->mdd_tx_events.count : vf->mdd_rx_events.count,
+               pf->hw.pf_id,
+               vf->vf_id,
+               vf->default_lan_addr.addr,
+               str_on_off(test_bit(I40E_FLAG_MDD_AUTO_RESET_VF, pf->flags)));
+}
+
+/**
+ * i40e_print_vfs_mdd_events - print VFs malicious driver detect event
+ * @pf: pointer to the PF structure
+ *
+ * Called from i40e_handle_mdd_event to rate limit and print VFs MDD events.
+ */
+static void i40e_print_vfs_mdd_events(struct i40e_pf *pf)
+{
+       unsigned int i;
+
+       /* check that there are pending MDD events to print */
+       if (!test_and_clear_bit(__I40E_MDD_VF_PRINT_PENDING, pf->state))
+               return;
+
+       if (!__ratelimit(&pf->mdd_message_rate_limit))
+               return;
+
+       for (i = 0; i < pf->num_alloc_vfs; i++) {
+               struct i40e_vf *vf = &pf->vf[i];
+               bool is_printed = false;
+
+               /* only print Rx MDD event message if there are new events */
+               if (vf->mdd_rx_events.count != vf->mdd_rx_events.last_printed) {
+                       vf->mdd_rx_events.last_printed = 
vf->mdd_rx_events.count;
+                       i40e_print_vf_mdd_event(pf, vf, false);
+                       is_printed = true;
+               }
+
+               /* only print Tx MDD event message if there are new events */
+               if (vf->mdd_tx_events.count != vf->mdd_tx_events.last_printed) {
+                       vf->mdd_tx_events.last_printed = 
vf->mdd_tx_events.count;
+                       i40e_print_vf_mdd_event(pf, vf, true);
+                       is_printed = true;
+               }
+
+               if (is_printed && !test_bit(I40E_FLAG_MDD_AUTO_RESET_VF, 
pf->flags))
+                       dev_info(&pf->pdev->dev,
+                                "Use PF Control I/F to re-enable the VF #%d\n",
+                                i);
+       }
+}
+
 /**
  * i40e_handle_mdd_event
  * @pf: pointer to the PF structure
  *
  * Called from the MDD irq handler to identify possibly malicious vfs
  **/
 static void i40e_handle_mdd_event(struct i40e_pf *pf)
 {
        struct i40e_hw *hw = &pf->hw;
        bool mdd_detected = false;
        struct i40e_vf *vf;
        u32 reg;
        int i;
 
-       if (!test_bit(__I40E_MDD_EVENT_PENDING, pf->state))
+       if (!test_and_clear_bit(__I40E_MDD_EVENT_PENDING, pf->state)) {
+               /* Since the VF MDD event logging is rate limited, check if
+                * there are pending MDD events.
+                */
+               i40e_print_vfs_mdd_events(pf);
                return;
+       }
 
        /* find what triggered the MDD event */
        reg = rd32(hw, I40E_GL_MDET_TX);
@@ -11248,36 +11314,48 @@ static void i40e_handle_mdd_event(struct i40e_pf *pf)
 
        /* see if one of the VFs needs its hand slapped */
        for (i = 0; i < pf->num_alloc_vfs && mdd_detected; i++) {
+               bool is_mdd_on_tx = false;
+               bool is_mdd_on_rx = false;
+
                vf = &(pf->vf[i]);
                reg = rd32(hw, I40E_VP_MDET_TX(i));
                if (reg & I40E_VP_MDET_TX_VALID_MASK) {
+                       set_bit(__I40E_MDD_VF_PRINT_PENDING, pf->state);
                        wr32(hw, I40E_VP_MDET_TX(i), 0xFFFF);
-                       vf->num_mdd_events++;
-                       dev_info(&pf->pdev->dev, "TX driver issue detected on 
VF %d\n",
-                                i);
-                       dev_info(&pf->pdev->dev,
-                                "Use PF Control I/F to re-enable the VF\n");
+                       vf->mdd_tx_events.count++;
                        set_bit(I40E_VF_STATE_DISABLED, &vf->vf_states);
+                       is_mdd_on_tx = true;
                }
 
                reg = rd32(hw, I40E_VP_MDET_RX(i));
                if (reg & I40E_VP_MDET_RX_VALID_MASK) {
+                       set_bit(__I40E_MDD_VF_PRINT_PENDING, pf->state);
                        wr32(hw, I40E_VP_MDET_RX(i), 0xFFFF);
-                       vf->num_mdd_events++;
-                       dev_info(&pf->pdev->dev, "RX driver issue detected on 
VF %d\n",
-                                i);
-                       dev_info(&pf->pdev->dev,
-                                "Use PF Control I/F to re-enable the VF\n");
+                       vf->mdd_rx_events.count++;
                        set_bit(I40E_VF_STATE_DISABLED, &vf->vf_states);
+                       is_mdd_on_rx = true;
+               }
+
+               if ((is_mdd_on_tx || is_mdd_on_rx) &&
+                   test_bit(I40E_FLAG_MDD_AUTO_RESET_VF, pf->flags)) {
+                       /* VF MDD event counters will be cleared by
+                        * reset, so print the event prior to reset.
+                        */
+                       if (is_mdd_on_rx)
+                               i40e_print_vf_mdd_event(pf, vf, false);
+                       if (is_mdd_on_tx)
+                               i40e_print_vf_mdd_event(pf, vf, true);
+
+                       i40e_vc_reset_vf(vf, true);
                }
        }
 
-       /* re-enable mdd interrupt cause */
-       clear_bit(__I40E_MDD_EVENT_PENDING, pf->state);
        reg = rd32(hw, I40E_PFINT_ICR0_ENA);
        reg |=  I40E_PFINT_ICR0_ENA_MAL_DETECT_MASK;
        wr32(hw, I40E_PFINT_ICR0_ENA, reg);
        i40e_flush(hw);
+
+       i40e_print_vfs_mdd_events(pf);
 }
 
 /**
@@ -15970,6 +16048,9 @@ static int i40e_probe(struct pci_dev *pdev, const 
struct pci_device_id *ent)
                         ERR_PTR(err),
                         i40e_aq_str(&pf->hw, pf->hw.aq.asq_last_status));
 
+       /* VF MDD event logs are rate limited to one second intervals */
+       ratelimit_state_init(&pf->mdd_message_rate_limit, 1 * HZ, 1);
+
        /* Reconfigure hardware for allowing smaller MSS in the case
         * of TSO, so that we avoid the MDD being fired and causing
         * a reset in the case of small MSS+TSO.
diff --git a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c 
b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
index 662622f..5b4618e 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
@@ -216,7 +216,7 @@ void i40e_vc_notify_vf_reset(struct i40e_vf *vf)
  * @notify_vf: notify vf about reset or not
  * Reset VF handler.
  **/
-static void i40e_vc_reset_vf(struct i40e_vf *vf, bool notify_vf)
+void i40e_vc_reset_vf(struct i40e_vf *vf, bool notify_vf)
 {
        struct i40e_pf *pf = vf->pf;
        int i;
diff --git a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.h 
b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.h
index 66f95e2..5cf74f1 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.h
+++ b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.h
@@ -64,6 +64,12 @@ struct i40evf_channel {
        u64 max_tx_rate; /* bandwidth rate allocation for VSIs */
 };
 
+struct i40e_mdd_vf_events {
+       u64 count;      /* total count of Rx|Tx events */
+       /* count number of the last printed event */
+       u64 last_printed;
+};
+
 /* VF information structure */
 struct i40e_vf {
        struct i40e_pf *pf;
@@ -92,7 +98,9 @@ struct i40e_vf {
 
        u8 num_queue_pairs;     /* num of qps assigned to VF vsis */
        u8 num_req_queues;      /* num of requested qps */
-       u64 num_mdd_events;     /* num of mdd events detected */
+       /* num of mdd tx and rx events detected */
+       struct i40e_mdd_vf_events mdd_rx_events;
+       struct i40e_mdd_vf_events mdd_tx_events;
 
        unsigned long vf_caps;  /* vf's adv. capabilities */
        unsigned long vf_states;        /* vf's runtime states */
@@ -120,6 +128,7 @@ int i40e_alloc_vfs(struct i40e_pf *pf, u16 num_alloc_vfs);
 int i40e_vc_process_vf_msg(struct i40e_pf *pf, s16 vf_id, u32 v_opcode,
                           u32 v_retval, u8 *msg, u16 msglen);
 int i40e_vc_process_vflr_event(struct i40e_pf *pf);
+void i40e_vc_reset_vf(struct i40e_vf *vf, bool notify_vf);
 bool i40e_reset_vf(struct i40e_vf *vf, bool flr);
 bool i40e_reset_all_vfs(struct i40e_pf *pf, bool flr);
 void i40e_vc_notify_vf_reset(struct i40e_vf *vf);
-- 
2.25.1

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