RE: [PATCH 3/6] net/vhost: enable compliant offloading mode

["Xia, Chenbo" <chenbo.xia@intel.com>]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Monday, May 16, 2022 9:29 PM
> To: Xia, Chenbo <chenbo.xia@intel.com>; dev@dpdk.org; jasowang@redhat.com;
> david.marchand@redhat.com; olivier.matz@6wind.com
> Cc: stable@dpdk.org
> Subject: Re: [PATCH 3/6] net/vhost: enable compliant offloading mode
> 
> Hi Chenbo,
> 
> On 5/16/22 15:26, Xia, Chenbo wrote:
> > Hi Maxime,
> >
> >> -----Original Message-----
> >> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> >> Sent: Thursday, May 5, 2022 6:27 PM
> >> To: dev@dpdk.org; jasowang@redhat.com; Xia, Chenbo
> <chenbo.xia@intel.com>;
> >> david.marchand@redhat.com; olivier.matz@6wind.com
> >> Cc: stable@dpdk.org; Maxime Coquelin <maxime.coquelin@redhat.com>
> >> Subject: [PATCH 3/6] net/vhost: enable compliant offloading mode
> >>
> >> This patch enables the compliant offloading flags mode by
> >> default, which prevents the Rx path to set Tx offload flags,
> >> which is illegal. A new legacy-ol-flags devarg is introduced
> >> to enable the legacy behaviour.
> >>
> >> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> >> ---
> >>   doc/guides/nics/vhost.rst         |  6 ++++++
> >>   drivers/net/vhost/rte_eth_vhost.c | 19 ++++++++++++++++---
> >>   2 files changed, 22 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/doc/guides/nics/vhost.rst b/doc/guides/nics/vhost.rst
> >> index ee802ec4a8..d7c0e2ade8 100644
> >> --- a/doc/guides/nics/vhost.rst
> >> +++ b/doc/guides/nics/vhost.rst
> >> @@ -64,6 +64,12 @@ The user can specify below arguments in `--vdev`
> option.
> >>       It is used to enable external buffer support in vhost library.
> >>       (Default: 0 (disabled))
> >>
> >> +#.  ``legacy-ol-flags``:
> >> +
> >> +    It is used to restore legacy behavior for offloading that was not
> >> +    compliant with offloading API.
> >> +    (Default: 0 (disabled))
> >> +
> >>   Vhost PMD event handling
> >>   ------------------------
> >>
> >> diff --git a/drivers/net/vhost/rte_eth_vhost.c
> >> b/drivers/net/vhost/rte_eth_vhost.c
> >> index 070f0e6dfd..0a2e8d9b29 100644
> >> --- a/drivers/net/vhost/rte_eth_vhost.c
> >> +++ b/drivers/net/vhost/rte_eth_vhost.c
> >> @@ -31,9 +31,10 @@ enum {VIRTIO_RXQ, VIRTIO_TXQ, VIRTIO_QNUM};
> >>   #define ETH_VHOST_CLIENT_ARG		"client"
> >>   #define ETH_VHOST_IOMMU_SUPPORT		"iommu-support"
> >>   #define ETH_VHOST_POSTCOPY_SUPPORT	"postcopy-support"
> >> -#define ETH_VHOST_VIRTIO_NET_F_HOST_TSO "tso"
> >> -#define ETH_VHOST_LINEAR_BUF  "linear-buffer"
> >> -#define ETH_VHOST_EXT_BUF  "ext-buffer"
> >> +#define ETH_VHOST_VIRTIO_NET_F_HOST_TSO	"tso"
> >> +#define ETH_VHOST_LINEAR_BUF		"linear-buffer"
> >> +#define ETH_VHOST_EXT_BUF		"ext-buffer"
> >> +#define ETH_VHOST_LEGACY_OL_FLAGS	"legacy-ol-flags"
> >>   #define VHOST_MAX_PKT_BURST 32
> >>
> >>   static const char *valid_arguments[] = {
> >> @@ -1563,6 +1564,7 @@ rte_pmd_vhost_probe(struct rte_vdev_device *dev)
> >>   	int tso = 0;
> >>   	int linear_buf = 0;
> >>   	int ext_buf = 0;
> >> +	int legacy_ol_flags = 0;
> >>   	struct rte_eth_dev *eth_dev;
> >>   	const char *name = rte_vdev_device_name(dev);
> >>
> >> @@ -1672,6 +1674,17 @@ rte_pmd_vhost_probe(struct rte_vdev_device *dev)
> >>   			flags |= RTE_VHOST_USER_EXTBUF_SUPPORT;
> >>   	}
> >>
> >> +	if (rte_kvargs_count(kvlist, ETH_VHOST_LEGACY_OL_FLAGS) == 1) {
> >> +		ret = rte_kvargs_process(kvlist,
> >> +				ETH_VHOST_LEGACY_OL_FLAGS,
> >> +				&open_int, &legacy_ol_flags);
> >> +		if (ret < 0)
> >> +			goto out_free;
> >> +	}
> >> +
> >> +	if (legacy_ol_flags == 0)
> >> +		flags |= RTE_VHOST_USER_NET_COMPLIANT_OL_FLAGS;
> >
> > Putting this check into above '{}' like other option does, will look
> better.
> 
> Actually, it would change the behavior because we want to set the flag
> even if legacy devrarg is not passed.

You're right...

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>

> 
> Regards,
> Maxime
> 
> > Thanks,
> > Chenbo
> >
> >> +
> >>   	if (dev->device.numa_node == SOCKET_ID_ANY)
> >>   		dev->device.numa_node = rte_socket_id();
> >>
> >> --
> >> 2.35.1
> >