From f23e0643cd0b53e68e283b6f26194d56c28a2eb1 Mon Sep 17 00:00:00 2001
From: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>
Date: Sun, 15 Apr 2018 18:53:36 -0500
Subject: [PATCH] ibmvnic: Clear pending interrupt after device reset

References: bsc#1089644
Patch-mainline: v4.17-rc2
Git-commit: f23e0643cd0b53e68e283b6f26194d56c28a2eb1

Due to a firmware bug, the hypervisor can send an interrupt to a
transmit or receive queue just prior to a partition migration, not
allowing the device enough time to handle it and send an EOI. When
the partition migrates, the interrupt is lost but an "EOI-pending"
flag for the interrupt line is still set in firmware. No further
interrupts will be sent until that flag is cleared, effectively
freezing that queue. To workaround this, the driver will disable the
hardware interrupt and send an H_EOI signal prior to re-enabling it.
This will flush the pending EOI and allow the driver to continue
operation.

Signed-off-by: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index f4a56a3c07ad..2df01ad98df7 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1049,16 +1049,14 @@ static int __ibmvnic_open(struct net_device *netdev)
 		netdev_dbg(netdev, "Enabling rx_scrq[%d] irq\n", i);
 		if (prev_state == VNIC_CLOSED)
 			enable_irq(adapter->rx_scrq[i]->irq);
-		else
-			enable_scrq_irq(adapter, adapter->rx_scrq[i]);
+		enable_scrq_irq(adapter, adapter->rx_scrq[i]);
 	}
 
 	for (i = 0; i < adapter->req_tx_queues; i++) {
 		netdev_dbg(netdev, "Enabling tx_scrq[%d] irq\n", i);
 		if (prev_state == VNIC_CLOSED)
 			enable_irq(adapter->tx_scrq[i]->irq);
-		else
-			enable_scrq_irq(adapter, adapter->tx_scrq[i]);
+		enable_scrq_irq(adapter, adapter->tx_scrq[i]);
 	}
 
 	rc = set_link_state(adapter, IBMVNIC_LOGICAL_LNK_UP);
@@ -1199,6 +1197,7 @@ static void ibmvnic_disable_irqs(struct ibmvnic_adapter *adapter)
 			if (adapter->tx_scrq[i]->irq) {
 				netdev_dbg(netdev,
 					   "Disabling tx_scrq[%d] irq\n", i);
+				disable_scrq_irq(adapter, adapter->tx_scrq[i]);
 				disable_irq(adapter->tx_scrq[i]->irq);
 			}
 	}
@@ -1208,6 +1207,7 @@ static void ibmvnic_disable_irqs(struct ibmvnic_adapter *adapter)
 			if (adapter->rx_scrq[i]->irq) {
 				netdev_dbg(netdev,
 					   "Disabling rx_scrq[%d] irq\n", i);
+				disable_scrq_irq(adapter, adapter->rx_scrq[i]);
 				disable_irq(adapter->rx_scrq[i]->irq);
 			}
 		}
@@ -2617,12 +2617,19 @@ static int enable_scrq_irq(struct ibmvnic_adapter *adapter,
 {
 	struct device *dev = &adapter->vdev->dev;
 	unsigned long rc;
+	u64 val;
 
 	if (scrq->hw_irq > 0x100000000ULL) {
 		dev_err(dev, "bad hw_irq = %lx\n", scrq->hw_irq);
 		return 1;
 	}
 
+	val = (0xff000000) | scrq->hw_irq;
+	rc = plpar_hcall_norets(H_EOI, val);
+	if (rc)
+		dev_err(dev, "H_EOI FAILED irq 0x%llx. rc=%ld\n",
+			val, rc);
+
 	rc = plpar_hcall_norets(H_VIOCTL, adapter->vdev->unit_address,
 				H_ENABLE_VIO_INTERRUPT, scrq->hw_irq, 0, 0);
 	if (rc)
-- 
2.13.6