[dpdk-dev] [PATCH resend] virtio: fix link state regression

[dpdk-dev] [PATCH resend] virtio: fix link state regression

[Stephen Hemminger]

Support for link state interrupt was broken on virtio by

commit bda66c418c85 ("ethdev: add device fields from PCI layer")

This is caused because the actual value of drv_flags is not set
until after the resource_init has figured out whether it is using
UIO or direct I/O instructions.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

---

There maybe other drivers with the same problem. It would have
been better to move the structure elements (and break ABI) rather
than assume it safe to copy them.

 drivers/net/virtio/virtio_ethdev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 74c00ee..8e12804 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1289,11 +1289,11 @@ eth_virtio_dev_init(struct rte_eth_dev *eth_dev)
 
 	pci_dev = eth_dev->pci_dev;
 
-	rte_eth_copy_pci_info(eth_dev, pci_dev);
-
 	if (virtio_resource_init(pci_dev) < 0)
 		return -1;
 
+	rte_eth_copy_pci_info(eth_dev, pci_dev);
+
 	hw->use_msix = virtio_has_msix(&pci_dev->addr);
 	hw->io_base = (uint32_t)(uintptr_t)pci_dev->mem_resource[0].addr;
 
-- 
2.1.4

Re: [dpdk-dev] [PATCH resend] virtio: fix link state regression

[Iremonger, Bernard]

Hi Stephen,


> -----Original Message-----
> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> Sent: Friday, December 4, 2015 3:59 PM
> To: Xie, Huawei <huawei.xie@intel.com>; yuanhan.liu@linux.intel.com;
> Iremonger, Bernard <bernard.iremonger@intel.com>
> Cc: dev@dpdk.org; Stephen Hemminger <stephen@networkplumber.org>
> Subject: [PATCH resend] virtio: fix link state regression
> 
> Support for link state interrupt was broken on virtio by
> 
> commit bda66c418c85 ("ethdev: add device fields from PCI layer")
> 
> This is caused because the actual value of drv_flags is not set until after the
> resource_init has figured out whether it is using UIO or direct I/O
> instructions.
> 
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> 
> ---
> 
> There maybe other drivers with the same problem. It would have been
> better to move the structure elements (and break ABI) rather than assume it
> safe to copy them.
> 
>  drivers/net/virtio/virtio_ethdev.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_ethdev.c
> b/drivers/net/virtio/virtio_ethdev.c
> index 74c00ee..8e12804 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -1289,11 +1289,11 @@ eth_virtio_dev_init(struct rte_eth_dev
> *eth_dev)
> 
>  	pci_dev = eth_dev->pci_dev;
> 
> -	rte_eth_copy_pci_info(eth_dev, pci_dev);
> -
>  	if (virtio_resource_init(pci_dev) < 0)
>  		return -1;
> 
> +	rte_eth_copy_pci_info(eth_dev, pci_dev);
> +
>  	hw->use_msix = virtio_has_msix(&pci_dev->addr);
>  	hw->io_base = (uint32_t)(uintptr_t)pci_dev-
> >mem_resource[0].addr;
> 
> --
> 2.1.4

I think the call to rte_eth_copy_pci_info() needs to be a bit later.
After the following code:
	/* If host does not support status then disable LSC */
	if (!vtpci_with_feature(hw, VIRTIO_NET_F_STATUS))
		pci_dev->driver->drv_flags &= ~RTE_PCI_DRV_INTR_LSC;

I have submitted a patch for this earlier today

http://dpdk.org/dev/patchwork/patch/9345/

Regards,

Bernard.