[Intel-wired-lan] [PATCH iwl-next V1 11/15] ice: stop device before saving device states

[Lingyu Liu <lingyu.liu@intel.com>]

Stop device by disabling TX queue and RX queue.

ice_vfio_pci driver introduced in following patches from this
series needs this function when device state transits from
VFIO_DEVICE_STATE_RUNNING to VFIO_DEVICE_STATE_STOP.

Signed-off-by: Lingyu Liu <lingyu.liu@intel.com>
Signed-off-by: Yahui Cao <yahui.cao@intel.com>
---
 .../net/ethernet/intel/ice/ice_migration.c    | 68 +++++++++++++++++++
 include/linux/net/intel/ice_migration.h       |  5 ++
 2 files changed, 73 insertions(+)

diff --git a/drivers/net/ethernet/intel/ice/ice_migration.c b/drivers/net/ethernet/intel/ice/ice_migration.c
index c2a83a97af05..c588738828ab 100644
--- a/drivers/net/ethernet/intel/ice/ice_migration.c
+++ b/drivers/net/ethernet/intel/ice/ice_migration.c
@@ -2,6 +2,8 @@
 /* Copyright (C) 2018-2023 Intel Corporation */
 
 #include "ice.h"
+#include "ice_lib.h"
+#include "ice_fltr.h"
 #include "ice_base.h"
 #include "ice_txrx_lib.h"
 
@@ -172,6 +174,72 @@ void ice_migration_save_vf_msg(struct ice_vf *vf,
 	}
 }
 
+/**
+ * ice_migration_suspend_vf - suspend device on src
+ * @opaque: pointer to VF handler in ice vdev
+ * @is_dst: false: migration src true: migration dst
+ *
+ * Return 0 for success, negative for error
+ */
+int ice_migration_suspend_vf(void *opaque, bool is_dst)
+{
+	struct ice_vf *vf = (struct ice_vf *)opaque;
+	struct ice_vsi *vsi = ice_get_vf_vsi(vf);
+	struct ice_pf *pf = vf->pf;
+	struct device *dev;
+	int ret;
+
+	if (is_dst)
+		return 0;
+
+	dev = ice_pf_to_dev(pf);
+	if (vf->virtchnl_msg_num >= VIRTCHNL_MSG_MAX) {
+		dev_err(dev, "SR-IOV live migration disabled on VF %d. Migration buffer exceeded\n",
+			vf->vf_id);
+		return -EIO;
+	}
+
+	if (!vsi) {
+		dev_err(dev, "VF %d VSI is NULL\n", vf->vf_id);
+		return -EINVAL;
+	}
+	/* Prevent VSI from incoming packets by removing all filters before
+	 * stop rx ring and draining the traffic. There are possibilities that
+	 * rx ring head value jitters when rx ring is stopped with large amount
+	 * of packets incoming. In this case, HW mismatches SW on rx ring head
+	 * state. As a result, after restoring rx ring head on the destination
+	 * VM, the missing rx descriptors will never be written back, causing
+	 * packets receiving failure and dropped.
+	 */
+	ice_fltr_remove_all(vsi);
+	/* MAC based filter rule is disabled at this point. Set MAC to zero
+	 * to keep consistency when using ip link to display MAC address.
+	 */
+	eth_zero_addr(vf->hw_lan_addr);
+	eth_zero_addr(vf->dev_lan_addr);
+	/* For the tx side, there is possibility that some descriptors are
+	 * still pending to be transmitted by HW. Since VM is stopped now,
+	 * wait a while to make sure all the transmission is completed.
+	 * For the rx side, head value jittering may happen in case of high
+	 * packet rate. Since all forwarding filters are removed now, wait a
+	 * while to make sure all the reception is completed and rx head no
+	 * longer moves.
+	 */
+	usleep_range(1000, 2000);
+	ret = ice_vsi_stop_lan_tx_rings(vsi, ICE_NO_RESET, vf->vf_id);
+	if (ret) {
+		dev_err(dev, "VF %d failed to stop tx rings\n", vf->vf_id);
+		return -EIO;
+	}
+	ret = ice_vsi_stop_all_rx_rings(vsi);
+	if (ret) {
+		dev_err(dev, "VF %d failed to stop rx rings\n", vf->vf_id);
+		return -EIO;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(ice_migration_suspend_vf);
+
 static int
 ice_migration_save_rx_head(struct ice_vf *vf,
 			   struct ice_migration_dev_state *devstate)
diff --git a/include/linux/net/intel/ice_migration.h b/include/linux/net/intel/ice_migration.h
index b59200a0a059..45c3469df55d 100644
--- a/include/linux/net/intel/ice_migration.h
+++ b/include/linux/net/intel/ice_migration.h
@@ -16,6 +16,7 @@ void *ice_migration_get_vf(struct pci_dev *vf_pdev);
 void ice_migration_put_vf(void *opaque);
 void ice_migration_init_vf(void *opaque);
 void ice_migration_uninit_vf(void *opaque);
+int ice_migration_suspend_vf(void *opaque, bool mig_dst);
 int ice_migration_save_devstate(void *opaque, u8 *buf, u64 buf_sz);
 int ice_migration_restore_devstate(void *opaque, const u8 *buf, u64 buf_sz,
 				   struct vfio_device *vdev);
@@ -31,6 +32,10 @@ static inline void ice_migration_put_vf(void *opaque)
 }
 static inline void ice_migration_init_vf(void *opaque) { }
 static inline void ice_migration_uninit_vf(void *opaque) { }
+static inline int ice_migration_suspend_vf(void *opaque, bool mig_dst)
+{
+	return 0;
+}
 static inline int ice_migration_save_devstate(void *opaque, u8 *buf, u64 buf_sz)
 {
 	return 0;
-- 
2.25.1

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