On 2018/01/18 18:42, Shrikrishna Khare wrote:
>
>
> On Thu, 18 Jan 2018, Benjamin Poirier wrote:
>
> > On 2018/01/18 15:50, Benjamin Poirier wrote:
> > > 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", v4.15-rc1). 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 | _OTHER) 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
> > > 16ecba59bc33 ("e1000e: Do not read ICR in Other interrupt", v4.5-rc1).
> >
> > vmware folks, please comment.
>
> Thank you for bringing this to our attention.
>
> Using the reported build (ESX 6.5, 7526125) and 4.15.0-rc8+ kernel (which
> has the said patch), I could bring up e1000e interface (version: 3.2.6-k),
> get dhcp address and even do large file downloads without difficulty.
>
> Could you give us more pointers on how we may be able to reproduce this
> locally? Was there anything different with the configuration when the
> issue was observed? Is the issue consistently reproducible?
It's consistently reproducible, however I noticed that once in a while
there is a genuine "Other" interrupt that comes in and triggers the link
status change. The problem is with interrupts that are triggered via a
write to ICS (such as in e1000e_trigger_lsc()). Can you reproduce a
problem if you do:
ip link set ethX down
ip link set ethX up
If you're building your own kernel, you can add the following patch and
cat /sys/kernel/debug/tracing/trace_pipe
For me it shows on v4.15-rc8:
<...>-2578 [000] .... 83527.938321: e1000e_trigger_lsc: trigger_lsc
<...>-2578 [000] d.h. 83527.938398: e1000_msix_other: icr 0x0
With the patch that I submitted, it shows:
wickedd-1329 [002] .N.. 20.123545: e1000e_trigger_lsc: trigger_lsc
<idle>-0 [000] d.h. 20.123630: e1000_msix_other: icr 0x81000004
<idle>-0 [000] d.h. 20.123654: e1000_msix_other: lsc
<idle>-0 [000] d.h. 20.123676: e1000_msix_other: mod_timer
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c
b/drivers/net/ethernet/intel/e1000e/netdev.c
index 9f18d39bdc8f..16620ce840fc 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -1918,22 +1918,29 @@ static irqreturn_t e1000_msix_other(int __always_unused
irq, void *data)
bool enable = true;
icr = er32(ICR);
+ trace_printk("icr 0x%x\n", icr);
+
if (icr & E1000_ICR_RXO) {
+ trace_printk("rxo\n");
ew32(ICR, E1000_ICR_RXO);
enable = false;
/* napi poll will re-enable Other, make sure it runs */
if (napi_schedule_prep(&adapter->napi)) {
+ trace_printk("napi schedule\n");
adapter->total_rx_bytes = 0;
adapter->total_rx_packets = 0;
__napi_schedule(&adapter->napi);
}
}
if (icr & E1000_ICR_LSC) {
+ trace_printk("lsc\n");
ew32(ICR, E1000_ICR_LSC);
hw->mac.get_link_status = true;
/* guard against interrupt when we're going down */
- if (!test_bit(__E1000_DOWN, &adapter->state))
+ if (!test_bit(__E1000_DOWN, &adapter->state)) {
+ trace_printk("mod_timer\n");
mod_timer(&adapter->watchdog_timer, jiffies + 1);
+ }
}
if (enable && !test_bit(__E1000_DOWN, &adapter->state))
@@ -4221,6 +4228,8 @@ static void e1000e_trigger_lsc(struct e1000_adapter
*adapter)
{
struct e1000_hw *hw = &adapter->hw;
+ trace_printk("trigger_lsc\n");
+
if (adapter->msix_entries)
ew32(ICS, E1000_ICS_LSC | E1000_ICS_OTHER);
else
