netdev - [PATCH 3/3] Revert "e1000e: Do not read ICR in Other interrupt"

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Date:   Fri, 26 Jan 2018 18:12:36 +0900
From:   Benjamin Poirier <bpoirier@...e.com>
To:     Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Cc:     Alexander Duyck <alexander.duyck@...il.com>,
        intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] Revert "e1000e: Do not read ICR in Other interrupt"

This reverts commit 16ecba59bc333d6282ee057fb02339f77a880beb.

It was reported that emulated e1000e devices in vmware esxi 6.5 Build
7526125 do not link up after commit 4aea7a5c5e94 ("e1000e: Avoid receiver
overrun interrupt bursts"). Some tracing shows that after
e1000e_trigger_lsc() is called, ICR reads out as 0x0 in e1000_msix_other()
on emulated e1000e devices. In comparison, on real e1000e 82574 hardware,
icr=0x80000004 (_INT_ASSERTED | _LSC) in the same situation.

Some experimentation showed that this flaw in vmware e1000e emulation can
be worked around by not setting Other in EIAC. This is how it was before
commit 16ecba59bc33 ("e1000e: Do not read ICR in Other interrupt").

Since the ICR read in the Other interrupt handler has already been
restored, this patch effectively reverts the remainder of commit
16ecba59bc33 ("e1000e: Do not read ICR in Other interrupt").

Fixes: 4aea7a5c5e94 ("e1000e: Avoid receiver overrun interrupt bursts")
Signed-off-by: Benjamin Poirier <bpoirier@...e.com>
---
 drivers/net/ethernet/intel/e1000e/netdev.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index ed103b9a8d3a..fffc1f0e3895 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -1916,6 +1916,13 @@ static irqreturn_t e1000_msix_other(int __always_unused irq, void *data)
 	struct e1000_hw *hw = &adapter->hw;
 	u32 icr = er32(ICR);

+	/* Certain events (such as RXO) which trigger Other do not set
+	 * INT_ASSERTED. In that case, read to clear of icr does not take
+	 * place.
+	 */
+	if (!(icr & E1000_ICR_INT_ASSERTED))
+		ew32(ICR, E1000_ICR_OTHER);
+
 	if (icr & adapter->eiac_mask)
 		ew32(ICS, (icr & adapter->eiac_mask));

@@ -2033,7 +2040,6 @@ static void e1000_configure_msix(struct e1000_adapter *adapter)
 		       hw->hw_addr + E1000_EITR_82574(vector));
 	else
 		writel(1, hw->hw_addr + E1000_EITR_82574(vector));
-	adapter->eiac_mask |= E1000_IMS_OTHER;

 	/* Cause Tx interrupts on every write back */
 	ivar |= BIT(31);
@@ -2258,7 +2264,7 @@ static void e1000_irq_enable(struct e1000_adapter *adapter)

 	if (adapter->msix_entries) {
 		ew32(EIAC_82574, adapter->eiac_mask & E1000_EIAC_MASK_82574);
-		ew32(IMS, adapter->eiac_mask | E1000_IMS_LSC);
+		ew32(IMS, adapter->eiac_mask | E1000_IMS_OTHER | E1000_IMS_LSC);
 	} else if (hw->mac.type >= e1000_pch_lpt) {
 		ew32(IMS, IMS_ENABLE_MASK | E1000_IMS_ECCER);
 	} else {
-- 
2.15.1