On 4/5/24 15:01, Eric Garver wrote:
> On Fri, Apr 05, 2024 at 11:39:58AM +0200, Eelco Chaudron wrote:
>>
>>
>> On 3 Apr 2024, at 16:35, Eric Garver wrote:
>>
>>> Kernel support has been added for this action. As such, we need to probe
>>> the datapath for support.
>>>
>>> Signed-off-by: Eric Garver <e...@garver.life>
>>> ---
>>> include/linux/openvswitch.h | 2 +-
>>> lib/dpif.c | 6 ++-
>>> lib/dpif.h | 2 +-
>>> ofproto/ofproto-dpif.c | 77 ++++++++++++++++++++++++++++++++++---
>>> ofproto/ofproto-dpif.h | 4 +-
>>> 5 files changed, 81 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/include/linux/openvswitch.h b/include/linux/openvswitch.h
>>> index d18754c84f62..d9fb991ef234 100644
>>> --- a/include/linux/openvswitch.h
>>> +++ b/include/linux/openvswitch.h
>>> @@ -1086,11 +1086,11 @@ enum ovs_action_attr {
>>> OVS_ACTION_ATTR_CHECK_PKT_LEN, /* Nested OVS_CHECK_PKT_LEN_ATTR_*. */
>>> OVS_ACTION_ATTR_ADD_MPLS, /* struct ovs_action_add_mpls. */
>>> OVS_ACTION_ATTR_DEC_TTL, /* Nested OVS_DEC_TTL_ATTR_*. */
>>> + OVS_ACTION_ATTR_DROP, /* u32 xlate_error. */
>>>
>>> #ifndef __KERNEL__
>>> OVS_ACTION_ATTR_TUNNEL_PUSH, /* struct ovs_action_push_tnl*/
>>> OVS_ACTION_ATTR_TUNNEL_POP, /* u32 port number. */
>>> - OVS_ACTION_ATTR_DROP, /* u32 xlate_error. */
>>> OVS_ACTION_ATTR_LB_OUTPUT, /* u32 bond-id. */
>>> #endif
>>> __OVS_ACTION_ATTR_MAX, /* Nothing past this will be accepted
>>> diff --git a/lib/dpif.c b/lib/dpif.c
>>> index 0f480bec48d0..23eb18495a66 100644
>>> --- a/lib/dpif.c
>>> +++ b/lib/dpif.c
>>> @@ -28,6 +28,7 @@
>>> #include "dpctl.h"
>>> #include "dpif-netdev.h"
>>> #include "flow.h"
>>> +#include "netdev-offload.h"
>>> #include "netdev-provider.h"
>>> #include "netdev.h"
>>> #include "netlink.h"
>>> @@ -1935,9 +1936,10 @@ dpif_supports_tnl_push_pop(const struct dpif *dpif)
>>> }
>>>
>>> bool
>>> -dpif_supports_explicit_drop_action(const struct dpif *dpif)
>>> +dpif_may_support_explicit_drop_action(const struct dpif *dpif)
>>> {
>>> - return dpif_is_netdev(dpif);
>>> + /* TC does not support offloading this action. */
>>> + return dpif_is_netdev(dpif) || !netdev_is_flow_api_enabled();
>>> }
>>>
>>> bool
>>> diff --git a/lib/dpif.h b/lib/dpif.h
>>> index 0f2dc2ef3c55..a764e8a592bd 100644
>>> --- a/lib/dpif.h
>>> +++ b/lib/dpif.h
>>> @@ -940,7 +940,7 @@ int dpif_get_pmds_for_port(const struct dpif * dpif,
>>> odp_port_t port_no,
>>>
>>> char *dpif_get_dp_version(const struct dpif *);
>>> bool dpif_supports_tnl_push_pop(const struct dpif *);
>>> -bool dpif_supports_explicit_drop_action(const struct dpif *);
>>> +bool dpif_may_support_explicit_drop_action(const struct dpif *);
>>> bool dpif_synced_dp_layers(struct dpif *);
>>>
>>> /* Log functions. */
>>> diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
>>> index c4e2e867ecdc..32d037be607c 100644
>>> --- a/ofproto/ofproto-dpif.c
>>> +++ b/ofproto/ofproto-dpif.c
>>> @@ -221,6 +221,7 @@ static void ct_zone_config_init(struct dpif_backer
>>> *backer);
>>> static void ct_zone_config_uninit(struct dpif_backer *backer);
>>> static void ct_zone_timeout_policy_sweep(struct dpif_backer *backer);
>>> static void ct_zone_limits_commit(struct dpif_backer *backer);
>>> +static bool recheck_support_explicit_drop_action(struct dpif_backer
>>> *backer);
>>>
>>> static inline struct ofproto_dpif *
>>> ofproto_dpif_cast(const struct ofproto *ofproto)
>>> @@ -391,6 +392,10 @@ type_run(const char *type)
>>> udpif_set_threads(backer->udpif, n_handlers, n_revalidators);
>>> }
>>>
>>> + if (recheck_support_explicit_drop_action(backer)) {
>>> + backer->need_revalidate = REV_RECONFIGURE;
>>> + }
>>> +
>>> if (backer->need_revalidate) {
>>> struct ofproto_dpif *ofproto;
>>> struct simap_node *node;
>>> @@ -855,7 +860,11 @@ ovs_native_tunneling_is_on(struct ofproto_dpif
>>> *ofproto)
>>> bool
>>> ovs_explicit_drop_action_supported(struct ofproto_dpif *ofproto)
>>> {
>>> - return ofproto->backer->rt_support.explicit_drop_action;
>>> + bool value;
>>> +
>>> + atomic_read_relaxed(&ofproto->backer->rt_support.explicit_drop_action,
>>> + &value);
>>> + return value;
>>> }
>>>
>>> bool
>>> @@ -1379,6 +1388,40 @@ check_ct_timeout_policy(struct dpif_backer *backer)
>>> return !error;
>>> }
>>>
>>> +/* Tests whether backer's datapath supports the OVS_ACTION_ATTR_DROP
>>> action. */
>>> +static bool
>>> +check_drop_action(struct dpif_backer *backer)
>>> +{
>>> + struct odputil_keybuf keybuf;
>>> + uint8_t actbuf[NL_A_U32_SIZE];
>>> + struct ofpbuf actions;
>>> + struct ofpbuf key;
>>> + bool supported;
>>> +
>>> + struct flow flow = {
>>> + .dl_type = CONSTANT_HTONS(0x1234), /* bogus */
>>> + };
>>> + struct odp_flow_key_parms odp_parms = {
>>> + .flow = &flow,
>>> + .probe = true,
>>> + };
>>> +
>>> + ofpbuf_use_stack(&key, &keybuf, sizeof keybuf);
>>> + odp_flow_key_from_flow(&odp_parms, &key);
>>> +
>>> + ofpbuf_use_stack(&actions, &actbuf, sizeof actbuf);
>>> + nl_msg_put_u32(&actions, OVS_ACTION_ATTR_DROP, XLATE_OK);
>>> +
>>> + supported = dpif_may_support_explicit_drop_action(backer->dpif) &&
>>> + dpif_probe_feature(backer->dpif, "drop", &key, &actions,
>>> NULL);
>>> +
>>> + VLOG_INFO("%s: Datapath %s explicit drop action",
>>> + dpif_name(backer->dpif),
>>> + (supported) ? "supports" : "does not support");
>>> +
>>> + return supported;
>>> +}
>>> +
>>> /* Tests whether 'backer''s datapath supports the all-zero SNAT case. */
>>> static bool
>>> dpif_supports_ct_zero_snat(struct dpif_backer *backer)
>>> @@ -1649,8 +1692,8 @@ check_support(struct dpif_backer *backer)
>>> backer->rt_support.max_hash_alg = check_max_dp_hash_alg(backer);
>>> backer->rt_support.check_pkt_len = check_check_pkt_len(backer);
>>> backer->rt_support.ct_timeout = check_ct_timeout_policy(backer);
>>> - backer->rt_support.explicit_drop_action =
>>> - dpif_supports_explicit_drop_action(backer->dpif);
>>> + atomic_store_relaxed(&backer->rt_support.explicit_drop_action,
>>> + check_drop_action(backer));
>>> backer->rt_support.lb_output_action =
>>> dpif_supports_lb_output_action(backer->dpif);
>>> backer->rt_support.ct_zero_snat = dpif_supports_ct_zero_snat(backer);
>>> @@ -1667,6 +1710,28 @@ check_support(struct dpif_backer *backer)
>>> backer->rt_support.odp.nd_ext = check_nd_extensions(backer);
>>> }
>>>
>>> +/* TC does not support offloading the explicit drop action. As such we
>>> need to
>>> + * re-probe the datapath if hw-offload has been modified.
>>> + * Note: We don't support true --> false transition as that requires a
>>> restart.
>>> + * See netdev_set_flow_api_enabled(). */
>>> +static bool
>>> +recheck_support_explicit_drop_action(struct dpif_backer *backer)
>>> +{
>>> + bool explicit_drop_action;
>>> +
>>> + atomic_read_relaxed(&backer->rt_support.explicit_drop_action,
>>> + &explicit_drop_action);
>>> +
>>> + if (explicit_drop_action
>>> + && !dpif_may_support_explicit_drop_action(backer->dpif)) {
>>> + ovs_assert(!check_drop_action(backer));
>>
>> If we only call this for the log message, would just adding the log message
>> here not be better?
>> It avoids the installation of a flow,
We're not going to install the flow, because there is a check for
dpif_may_support_explicit_drop_action() in the check_drop_action().
>> and I have not thought this through, but it might confuse the revalidator.
So, the revalidator will not be confused.
>
> So you and Ilya would rather I insert a VLOG_INFO() here? That's fine
> with me.
I'd keep as is, unless Eelco has a strong opinion towards the log.
>
> Can we agree on the message before I post another revision?
>
> VLOG_INFO("%s: Datapath supports explicit drop action, "
> "but disabled due to hw-offload=true.",
> dpif_name(backer->dpif))
>
> Is that agreeable?
>
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