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Mon, 02 Jun 2025 20:19:15 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHywPCLM/Qh3jSdbKsF9dOuO472rVd+vIBVeTePaa/6GUJRTTw4v5rkd8bePaost/OoMXAMwCrz5QAOrqb7r5E= X-Received: by 2002:a17:902:e849:b0:234:8a4a:ada5 with SMTP id d9443c01a7336-23529904f21mr247667985ad.37.1748920754675; Mon, 02 Jun 2025 20:19:14 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20250530-rss-v12-0-95d8b348de91@daynix.com> <20250530-rss-v12-1-95d8b348de91@daynix.com> In-Reply-To: <20250530-rss-v12-1-95d8b348de91@daynix.com> From: Jason Wang Date: Tue, 3 Jun 2025 11:19:03 +0800 X-Gm-Features: AX0GCFv2w2DYNXanInKBc5HQRF8lqBk-gAKp63FMQ8nnSSAfo4iUv1CXTbXlSAw Message-ID: Subject: Re: [PATCH net-next v12 01/10] virtio_net: Add functions for hashing To: Akihiko Odaki Cc: Jonathan Corbet , Willem de Bruijn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , "Michael S. Tsirkin" , Xuan Zhuo , Shuah Khan , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-kselftest@vger.kernel.org, Yuri Benditovich , Andrew Melnychenko , Stephen Hemminger , gur.stavi@huawei.com, Lei Yang , Simon Horman Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, May 30, 2025 at 12:50=E2=80=AFPM Akihiko Odaki wrote: > > They are useful to implement VIRTIO_NET_F_RSS and > VIRTIO_NET_F_HASH_REPORT. > > Signed-off-by: Akihiko Odaki > Tested-by: Lei Yang > --- > include/linux/virtio_net.h | 188 +++++++++++++++++++++++++++++++++++++++= ++++++ > 1 file changed, 188 insertions(+) > > diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h > index 02a9f4dc594d..426f33b4b824 100644 > --- a/include/linux/virtio_net.h > +++ b/include/linux/virtio_net.h > @@ -9,6 +9,194 @@ > #include > #include > > +struct virtio_net_hash { > + u32 value; > + u16 report; > +}; > + > +struct virtio_net_toeplitz_state { > + u32 hash; > + const u32 *key; > +}; > + > +#define VIRTIO_NET_SUPPORTED_HASH_TYPES (VIRTIO_NET_RSS_HASH_TYPE_IPv4 |= \ > + VIRTIO_NET_RSS_HASH_TYPE_TCPv4 |= \ > + VIRTIO_NET_RSS_HASH_TYPE_UDPv4 |= \ > + VIRTIO_NET_RSS_HASH_TYPE_IPv6 | = \ > + VIRTIO_NET_RSS_HASH_TYPE_TCPv6 |= \ > + VIRTIO_NET_RSS_HASH_TYPE_UDPv6) > + > +#define VIRTIO_NET_RSS_MAX_KEY_SIZE 40 > + > +static inline void virtio_net_toeplitz_convert_key(u32 *input, size_t le= n) > +{ > + while (len >=3D sizeof(*input)) { > + *input =3D be32_to_cpu((__force __be32)*input); > + input++; > + len -=3D sizeof(*input); > + } > +} > + > +static inline void virtio_net_toeplitz_calc(struct virtio_net_toeplitz_s= tate *state, > + const __be32 *input, size_t l= en) > +{ > + while (len >=3D sizeof(*input)) { > + for (u32 map =3D be32_to_cpu(*input); map; map &=3D (map = - 1)) { > + u32 i =3D ffs(map); > + > + state->hash ^=3D state->key[0] << (32 - i) | > + (u32)((u64)state->key[1] >> i); > + } > + > + state->key++; > + input++; > + len -=3D sizeof(*input); > + } > +} > + > +static inline u8 virtio_net_hash_key_length(u32 types) > +{ > + size_t len =3D 0; > + > + if (types & VIRTIO_NET_HASH_REPORT_IPv4) > + len =3D max(len, > + sizeof(struct flow_dissector_key_ipv4_addrs)); > + > + if (types & > + (VIRTIO_NET_HASH_REPORT_TCPv4 | VIRTIO_NET_HASH_REPORT_UDPv4)= ) > + len =3D max(len, > + sizeof(struct flow_dissector_key_ipv4_addrs) + > + sizeof(struct flow_dissector_key_ports)); > + > + if (types & VIRTIO_NET_HASH_REPORT_IPv6) > + len =3D max(len, > + sizeof(struct flow_dissector_key_ipv6_addrs)); > + > + if (types & > + (VIRTIO_NET_HASH_REPORT_TCPv6 | VIRTIO_NET_HASH_REPORT_UDPv6)= ) > + len =3D max(len, > + sizeof(struct flow_dissector_key_ipv6_addrs) + > + sizeof(struct flow_dissector_key_ports)); > + > + return len + sizeof(u32); > +} > + > +static inline u32 virtio_net_hash_report(u32 types, > + const struct flow_keys_basic *ke= ys) > +{ > + switch (keys->basic.n_proto) { > + case cpu_to_be16(ETH_P_IP): > + if (!(keys->control.flags & FLOW_DIS_IS_FRAGMENT)) { > + if (keys->basic.ip_proto =3D=3D IPPROTO_TCP && > + (types & VIRTIO_NET_RSS_HASH_TYPE_TCPv4)) > + return VIRTIO_NET_HASH_REPORT_TCPv4; > + > + if (keys->basic.ip_proto =3D=3D IPPROTO_UDP && > + (types & VIRTIO_NET_RSS_HASH_TYPE_UDPv4)) > + return VIRTIO_NET_HASH_REPORT_UDPv4; > + } > + > + if (types & VIRTIO_NET_RSS_HASH_TYPE_IPv4) > + return VIRTIO_NET_HASH_REPORT_IPv4; > + > + return VIRTIO_NET_HASH_REPORT_NONE; > + > + case cpu_to_be16(ETH_P_IPV6): > + if (!(keys->control.flags & FLOW_DIS_IS_FRAGMENT)) { > + if (keys->basic.ip_proto =3D=3D IPPROTO_TCP && > + (types & VIRTIO_NET_RSS_HASH_TYPE_TCPv6)) > + return VIRTIO_NET_HASH_REPORT_TCPv6; > + > + if (keys->basic.ip_proto =3D=3D IPPROTO_UDP && > + (types & VIRTIO_NET_RSS_HASH_TYPE_UDPv6)) > + return VIRTIO_NET_HASH_REPORT_UDPv6; > + } > + > + if (types & VIRTIO_NET_RSS_HASH_TYPE_IPv6) > + return VIRTIO_NET_HASH_REPORT_IPv6; > + > + return VIRTIO_NET_HASH_REPORT_NONE; > + > + default: > + return VIRTIO_NET_HASH_REPORT_NONE; > + } > +} > + > +static inline void virtio_net_hash_rss(const struct sk_buff *skb, > + u32 types, const u32 *key, > + struct virtio_net_hash *hash) > +{ > + struct virtio_net_toeplitz_state toeplitz_state =3D { .key =3D ke= y }; > + struct flow_keys flow; > + struct flow_keys_basic flow_basic; > + u16 report; > + > + if (!skb_flow_dissect_flow_keys(skb, &flow, 0)) { > + hash->report =3D VIRTIO_NET_HASH_REPORT_NONE; > + return; > + } > + > + flow_basic =3D (struct flow_keys_basic) { > + .control =3D flow.control, > + .basic =3D flow.basic > + }; > + > + report =3D virtio_net_hash_report(types, &flow_basic); > + > + switch (report) { > + case VIRTIO_NET_HASH_REPORT_IPv4: > + virtio_net_toeplitz_calc(&toeplitz_state, > + (__be32 *)&flow.addrs.v4addrs, > + sizeof(flow.addrs.v4addrs)); > + break; > + > + case VIRTIO_NET_HASH_REPORT_TCPv4: > + virtio_net_toeplitz_calc(&toeplitz_state, > + (__be32 *)&flow.addrs.v4addrs, > + sizeof(flow.addrs.v4addrs)); > + virtio_net_toeplitz_calc(&toeplitz_state, &flow.ports.por= ts, > + sizeof(flow.ports.ports)); > + break; > + > + case VIRTIO_NET_HASH_REPORT_UDPv4: > + virtio_net_toeplitz_calc(&toeplitz_state, > + (__be32 *)&flow.addrs.v4addrs, > + sizeof(flow.addrs.v4addrs)); > + virtio_net_toeplitz_calc(&toeplitz_state, &flow.ports.por= ts, > + sizeof(flow.ports.ports)); > + break; > + > + case VIRTIO_NET_HASH_REPORT_IPv6: > + virtio_net_toeplitz_calc(&toeplitz_state, > + (__be32 *)&flow.addrs.v6addrs, > + sizeof(flow.addrs.v6addrs)); > + break; > + > + case VIRTIO_NET_HASH_REPORT_TCPv6: > + virtio_net_toeplitz_calc(&toeplitz_state, > + (__be32 *)&flow.addrs.v6addrs, > + sizeof(flow.addrs.v6addrs)); > + virtio_net_toeplitz_calc(&toeplitz_state, &flow.ports.por= ts, > + sizeof(flow.ports.ports)); > + break; > + > + case VIRTIO_NET_HASH_REPORT_UDPv6: > + virtio_net_toeplitz_calc(&toeplitz_state, > + (__be32 *)&flow.addrs.v6addrs, > + sizeof(flow.addrs.v6addrs)); > + virtio_net_toeplitz_calc(&toeplitz_state, &flow.ports.por= ts, > + sizeof(flow.ports.ports)); > + break; > + > + default: > + hash->report =3D VIRTIO_NET_HASH_REPORT_NONE; > + return; So I still think we need a comment here to explain why this is not an issue if the device can report HASH_XXX_EX. Or we need to add the support, since this is the code from the driver side, I don't think we need to worry about the device implementation issues. For the issue of the number of options, does the spec forbid fallback to VIRTIO_NET_HASH_REPORT_NONE? If not, we can do that. Thanks > + } > + > + hash->value =3D toeplitz_state.hash; > + hash->report =3D report; > +} > + > static inline bool virtio_net_hdr_match_proto(__be16 protocol, __u8 gso_= type) > { > switch (gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { > > -- > 2.49.0 >