Hi Stephen,
It does not work because the netvsc device is not initialized with RTE_ETH_RSS_NONFRAG_IPV6_UDP capability according to the below snippet.

static void hn_rss_hash_init(struct hn_data *hv,
const struct rte_eth_rss_conf *rss_conf)
{
/* Convert from DPDK RSS hash flags to NDIS hash flags */
hv->rss_hash = NDIS_HASH_FUNCTION_TOEPLITZ;

if (rss_conf->rss_hf & RTE_ETH_RSS_IPV4)
hv->rss_hash |= NDIS_HASH_IPV4;
if (rss_conf->rss_hf & RTE_ETH_RSS_NONFRAG_IPV4_TCP)
hv->rss_hash |= NDIS_HASH_TCP_IPV4;
if (rss_conf->rss_hf & RTE_ETH_RSS_IPV6)
hv->rss_hash |= NDIS_HASH_IPV6;
if (rss_conf->rss_hf & RTE_ETH_RSS_IPV6_EX)
hv->rss_hash |= NDIS_HASH_IPV6_EX;
if (rss_conf->rss_hf & RTE_ETH_RSS_NONFRAG_IPV6_TCP)
hv->rss_hash |= NDIS_HASH_TCP_IPV6;
if (rss_conf->rss_hf & RTE_ETH_RSS_IPV6_TCP_EX)
hv->rss_hash |= NDIS_HASH_TCP_IPV6_EX;

memcpy(hv->rss_key, rss_conf->rss_key ? : rss_default_key,
NDIS_HASH_KEYSIZE_TOEPLITZ);
}

Since hn_dev_info_get merges the configuration of the netvsc device and VF using AND operation(in hn_vf_info_merge), even though VF(MLX5) supports RTE_ETH_RSS_NONFRAG_IPV6_UDP , the netvsc driver does not return this capability support to the app.
Why is RTE_ETH_RSS_NONFRAG_IPV6_UDP capability not supported by the netvsc driver?

Regards,
Nandini



On Wed, Aug 28, 2024 at 12:05 PM Stephen Hemminger <stephen@networkplumber.org> wrote:
On Wed, 28 Aug 2024 10:32:17 -0700
Nandini Rangaswamy <nandini.rangaswamy@broadcom.com> wrote:

> Hi Long and Stephen,
> I am trying to configure RSS offloads from my DPDK App with netvsc PMD.
> Netvsc seems to be supporting the following offloads:
> RTE_ETH_RSS_NONFRAG_IPV4_UDP RTE_ETH_RSS_NONFRAG_IPV4_TCP
> RTE_ETH_RSS_NONFRAG_IPV6_TCP RTE_ETH_RSS_IPV4
> RTE_ETH_RSS_IPV6
>
> However, the app is trying to configure the following offloads and failing:
>
> RTE_ETH_RSS_NONFRAG_IPV4_UDP
> RTE_ETH_RSS_NONFRAG_IPV4_TCP
> RTE_ETH_RSS_NONFRAG_IPV6_TCP
> RTE_ETH_RSS_NONFRAG_IPV6_UDP

Confusing, both of these overlap should work.
Please instrument the configure code in netvsc to see why it is complaining.

>
> Is it possible to bypass the netvsc PMD and configure these offloads on VF
> ? I am aware that app should not directly program the VF interface
> but for performance sake, I want the above offloads to be supported on VF.

No can't bypass driver.

You do need to configure multiqueue and enable RSS in configure
to get anything.

If you look at hn_rss_hash_init, the driver needs to convert the
requested flags into NDIS flags to tell the host what to do.

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