Re: [PATCH] ibmvnic: Clear pending interrupt after device reset

[David Miller]

From: Thomas Falcon 
Date: Sun, 15 Apr 2018 18:53:36 -0500

> 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 

Applied, thanks Thomas.

Re: [PATCH] ibmvnic: Clear pending interrupt after device reset

[David Miller]

From: Thomas Falcon 
Date: Sun, 15 Apr 2018 18:53:36 -0500

> 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 

Hey Thomas, I see two copies of this patch posted.  Any special
reason for that?

Thanks.

Re: [PATCH] ibmvnic: Clear pending interrupt after device reset

[Thomas Falcon]

On 04/15/2018 06:27 PM, Thomas Falcon wrote:
> 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.

Excuse me, I misspelled the linuxppc-dev email address.

Tom

> Signed-off-by: Thomas Falcon 
> ---
>  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 f84a920..ef7995fc 100644
> --- a/drivers/net/ethernet/ibm/ibmvnic.c
> +++ b/drivers/net/ethernet/ibm/ibmvnic.c
> @@ -1034,16 +1034,14 @@ 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);
> @@ -1184,6 +1182,7 @@ 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);
>   }
>   }
> @@ -1193,6 +1192,7 @@ 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);
>   }
>   }
> @@ -2601,12 +2601,19 @@ static int enable_scrq_irq(struct ibmvnic_adapter 
> *adapter,
>  {
>   struct device *dev = >vdev->dev;
>   unsigned long rc;
> + u64 val;
>
>   if (scrq->hw_irq > 0x1ULL) {
>   dev_err(dev, "bad hw_irq = %lx\n", scrq->hw_irq);
>   return 1;
>   }
>
> + val = (0xff00) | 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)