[dpdk-stable] [PATCH] net/virtio: fix read isr as MSI is enabled
Tan, Jianfeng
jianfeng.tan at intel.com
Thu Apr 6 07:40:15 CEST 2017
> -----Original Message-----
> From: Yuanhan Liu [mailto:yuanhan.liu at linux.intel.com]
> Sent: Thursday, April 6, 2017 1:36 PM
> To: Tan, Jianfeng
> Cc: Yang, Zhiyong; stable at dpdk.org; Stephen Hemminger
> Subject: Re: [dpdk-stable] [PATCH] net/virtio: fix read isr as MSI is enabled
>
> On Thu, Apr 06, 2017 at 05:30:10AM +0000, Tan, Jianfeng wrote:
> > Sorry, please just NACK this patch. (I'll do that in patchwork)
> >
> > I was sharing this half-baked patch with Zhiyong and forget to remove "CC".
> > Zhiyong and I are still working on this bug. Will send it out later.
>
> Oh, I didn't notice that this patch is not cc'ed to dev ml. Then you
> don't need update patchwork then (patchwork doesn't tract patches
> from stable list).
No wonder I did not find it. :-)
>
> --yliu
> >
> > Thanks,
> > Jianfeng
> >
> > > -----Original Message-----
> > > From: Yuanhan Liu [mailto:yuanhan.liu at linux.intel.com]
> > > Sent: Thursday, April 6, 2017 1:19 PM
> > > To: Tan, Jianfeng
> > > Cc: Yang, Zhiyong; stable at dpdk.org; Stephen Hemminger
> > > Subject: Re: [dpdk-stable] [PATCH] net/virtio: fix read isr as MSI is
> enabled
> > >
> > > On Tue, Mar 28, 2017 at 06:46:51AM +0000, Jianfeng Tan wrote:
> > > > We should not always check isr to know if link status is changed.
> > >
> > > Did this patch fix a real issue?
> > >
> > > > Here is how driver should handle interrupt quoted from virtio spec,
> > > >
> > > > If MSI-X capability is disabled:
> > > > – Read the ISR Status field, which will reset it to zero.
> > > > – If the lower bit is set: look through the used rings of all
> > > > virtqueues for the device, to see if any progress has been made
> > > > by the device which requires servicing.
> > > > – If the second lower bit is set: re-examine the configuration
> > > > space to see what changed.
> > > > If MSI-X capability is enabled:
> > > > – Look through the used rings of all virtqueues mapped to that
> > > > MSI-X vector for the device, to see if any progress has been
> > > > made by the device which requires servicing.
> > > > – If the MSI-X vector is equal to config_msix_vector, re-examine
> > > > the configuration space to see what changed
> > > >
> > > > Fixes: 8d6d7e5cb3b1 ("virtio: support link state interrupt")
> > > > CC: stable at dpdk.org
> > > >
> > > > CC: Stephen Hemminger <stephen at networkplumber.org>
> > > > Signed-off-by: Jianfeng Tan <jianfeng.tan at intel.com>
> > > > ---
> > > > drivers/net/virtio/virtio_ethdev.c | 22 +++++++++++++---------
> > > > 1 file changed, 13 insertions(+), 9 deletions(-)
> > > >
> > > > diff --git a/drivers/net/virtio/virtio_ethdev.c
> > > b/drivers/net/virtio/virtio_ethdev.c
> > > > index 3cf4102..cb30d11 100644
> > > > --- a/drivers/net/virtio/virtio_ethdev.c
> > > > +++ b/drivers/net/virtio/virtio_ethdev.c
> > > > @@ -36,6 +36,7 @@
> > > > #include <stdio.h>
> > > > #include <errno.h>
> > > > #include <unistd.h>
> > > > +#include <stdbool.h>
> > > >
> > > > #include <rte_ethdev.h>
> > > > #include <rte_memcpy.h>
> > > > @@ -1197,20 +1198,23 @@ virtio_interrupt_handler(struct
> rte_intr_handle
> > > *handle,
> > > > struct rte_eth_dev *dev = param;
> > > > struct virtio_hw *hw = dev->data->dev_private;
> > > > uint8_t isr;
> > > > + bool check_config;
> > > >
> > > > - /* Read interrupt status which clears interrupt */
> > > > - isr = vtpci_isr(hw);
> > > > - PMD_DRV_LOG(INFO, "interrupt status = %#x", isr);
> > > > + /* isr is used only when msix is not enabled */
> > > > + if (!hw->modern && !hw->use_msix) {
> > >
> > > The comment doesn't quite match the code: the hw->modern part is
> missing.
> > >
> > > > + isr = vtpci_isr(hw); /* Read to clears interrupt */
> > > > + PMD_DRV_LOG(INFO, "interrupt status = %#x", isr);
> > > > + check_config = (isr & VIRTIO_PCI_ISR_CONFIG) ? true : false;
> > >
> > > The "? :" is unnecessary.
> > >
> > > --yliu
> > >
> > > > + } else {
> > > > + check_config = true;
> > > > + }
> > > >
> > > > if (rte_intr_enable(handle) < 0)
> > > > PMD_DRV_LOG(ERR, "interrupt enable failed");
> > > >
> > > > - if (isr & VIRTIO_PCI_ISR_CONFIG) {
> > > > - if (virtio_dev_link_update(dev, 0) == 0)
> > > > - _rte_eth_dev_callback_process(dev,
> > > > -
> > > RTE_ETH_EVENT_INTR_LSC, NULL);
> > > > - }
> > > > -
> > > > + if (check_config && virtio_dev_link_update(dev, 0) == 0)
> > > > + _rte_eth_dev_callback_process(dev,
> > > > + RTE_ETH_EVENT_INTR_LSC, NULL);
> > > > }
> > > >
> > > > static void
> > > > --
> > > > 2.7.4
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