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

[Ma, WenwuX]

Hi Maxime,

> -----Original Message-----
> From: Xia, Chenbo <chenbo.xia at intel.com>
> Sent: 2022年5月16日 21:40
> To: Maxime Coquelin <maxime.coquelin at redhat.com>; dev at dpdk.org;
> jasowang at redhat.com; david.marchand at redhat.com;
> olivier.matz at 6wind.com
> Cc: stable at dpdk.org
> Subject: RE: [PATCH 3/6] net/vhost: enable compliant offloading mode
> 
> > -----Original Message-----
> > From: Maxime Coquelin <maxime.coquelin at redhat.com>
> > Sent: Monday, May 16, 2022 9:29 PM
> > To: Xia, Chenbo <chenbo.xia at intel.com>; dev at dpdk.org;
> > jasowang at redhat.com; david.marchand at redhat.com;
> olivier.matz at 6wind.com
> > Cc: stable at 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 at redhat.com>
> > >> Sent: Thursday, May 5, 2022 6:27 PM
> > >> To: dev at dpdk.org; jasowang at redhat.com; Xia, Chenbo
> > <chenbo.xia at intel.com>;
> > >> david.marchand at redhat.com; olivier.matz at 6wind.com
> > >> Cc: stable at dpdk.org; Maxime Coquelin <maxime.coquelin at 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 at 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
> > >>

ETH_VHOST_LEGACY_OL_FLAGS should be added into valid_arguments array.

static const char *valid_arguments[] = {
        ETH_VHOST_IFACE_ARG,
        ETH_VHOST_QUEUES_ARG,
        ETH_VHOST_CLIENT_ARG,
        ETH_VHOST_IOMMU_SUPPORT,
        ETH_VHOST_POSTCOPY_SUPPORT,
        ETH_VHOST_VIRTIO_NET_F_HOST_TSO,
        ETH_VHOST_LINEAR_BUF,
        ETH_VHOST_EXT_BUF,
        NULL
};

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