From: <psatheesh@marvell.com>
To: Nithin Dabilpuram <ndabilpuram@marvell.com>,
Kiran Kumar K <kirankumark@marvell.com>,
Sunil Kumar Kori <skori@marvell.com>,
Satha Rao <skoteshwar@marvell.com>,
Harman Kalra <hkalra@marvell.com>
Cc: <dev@dpdk.org>, Satheesh Paul <psatheesh@marvell.com>
Subject: [dpdk-dev] [PATCH 2/2] net/cnxk: support rte flow on cn20k
Date: Mon, 21 Oct 2024 09:31:44 +0530 [thread overview]
Message-ID: <20241021040144.974453-2-psatheesh@marvell.com> (raw)
In-Reply-To: <20241021040144.974453-1-psatheesh@marvell.com>
From: Satheesh Paul <psatheesh@marvell.com>
Support for rte flow in cn20k.
Signed-off-by: Satheesh Paul <psatheesh@marvell.com>
Reviewed-by: Kiran Kumar K <kirankumark@marvell.com>
---
drivers/net/cnxk/cn10k_ethdev.c | 8 +-
drivers/net/cnxk/cn10k_flow.h | 21 --
drivers/net/cnxk/cn20k_ethdev.c | 4 +
drivers/net/cnxk/cnxk_ethdev_devargs.c | 10 +-
drivers/net/cnxk/cnxk_flow.c | 10 +-
drivers/net/cnxk/cnxk_flow_wrapper.c | 303 +++++++++++++++++++++++++
drivers/net/cnxk/cnxk_flow_wrapper.h | 21 ++
drivers/net/cnxk/meson.build | 10 +-
8 files changed, 355 insertions(+), 32 deletions(-)
delete mode 100644 drivers/net/cnxk/cn10k_flow.h
create mode 100644 drivers/net/cnxk/cnxk_flow_wrapper.c
create mode 100644 drivers/net/cnxk/cnxk_flow_wrapper.h
diff --git a/drivers/net/cnxk/cn10k_ethdev.c b/drivers/net/cnxk/cn10k_ethdev.c
index fbb9b09062..a4b3d56c61 100644
--- a/drivers/net/cnxk/cn10k_ethdev.c
+++ b/drivers/net/cnxk/cn10k_ethdev.c
@@ -2,9 +2,9 @@
* Copyright(C) 2021 Marvell.
*/
#include "cn10k_ethdev.h"
-#include "cn10k_flow.h"
#include "cn10k_rx.h"
#include "cn10k_tx.h"
+#include "cnxk_flow_wrapper.h"
static uint16_t
nix_rx_offload_flags(struct rte_eth_dev *eth_dev)
@@ -913,9 +913,9 @@ npc_flow_ops_override(void)
init_once = 1;
/* Update platform specific ops */
- cnxk_flow_ops.create = cn10k_flow_create;
- cnxk_flow_ops.destroy = cn10k_flow_destroy;
- cnxk_flow_ops.info_get = cn10k_flow_info_get;
+ cnxk_flow_ops.create = cnxk_flow_create_wrapper;
+ cnxk_flow_ops.destroy = cnxk_flow_destroy_wrapper;
+ cnxk_flow_ops.info_get = cnxk_flow_info_get_wrapper;
}
static int
diff --git a/drivers/net/cnxk/cn10k_flow.h b/drivers/net/cnxk/cn10k_flow.h
deleted file mode 100644
index 316b74e6a6..0000000000
--- a/drivers/net/cnxk/cn10k_flow.h
+++ /dev/null
@@ -1,21 +0,0 @@
-/* SPDX-License-Identifier: BSD-3-Clause
- * Copyright(C) 2020 Marvell.
- */
-#ifndef __CN10K_RTE_FLOW_H__
-#define __CN10K_RTE_FLOW_H__
-
-#include <rte_flow_driver.h>
-
-struct rte_flow *cn10k_flow_create(struct rte_eth_dev *dev, const struct rte_flow_attr *attr,
- const struct rte_flow_item pattern[],
- const struct rte_flow_action actions[],
- struct rte_flow_error *error);
-int cn10k_flow_destroy(struct rte_eth_dev *dev, struct rte_flow *flow,
- struct rte_flow_error *error);
-
-int cn10k_flow_info_get(struct rte_eth_dev *dev, struct rte_flow_port_info *port_info,
- struct rte_flow_queue_info *queue_info, struct rte_flow_error *err);
-
-#define CN10K_NPC_COUNTERS_MAX 512
-
-#endif /* __CN10K_RTE_FLOW_H__ */
diff --git a/drivers/net/cnxk/cn20k_ethdev.c b/drivers/net/cnxk/cn20k_ethdev.c
index 37c372d80f..e74dd88172 100644
--- a/drivers/net/cnxk/cn20k_ethdev.c
+++ b/drivers/net/cnxk/cn20k_ethdev.c
@@ -4,6 +4,7 @@
#include "cn20k_ethdev.h"
#include "cn20k_rx.h"
#include "cn20k_tx.h"
+#include "cnxk_flow_wrapper.h"
static uint16_t
nix_rx_offload_flags(struct rte_eth_dev *eth_dev)
@@ -867,6 +868,9 @@ npc_flow_ops_override(void)
init_once = 1;
/* Update platform specific ops */
+ cnxk_flow_ops.create = cnxk_flow_create_wrapper;
+ cnxk_flow_ops.destroy = cnxk_flow_destroy_wrapper;
+ cnxk_flow_ops.info_get = cnxk_flow_info_get_wrapper;
}
static int
diff --git a/drivers/net/cnxk/cnxk_ethdev_devargs.c b/drivers/net/cnxk/cnxk_ethdev_devargs.c
index 5bd50bb9a1..bdf5d88b92 100644
--- a/drivers/net/cnxk/cnxk_ethdev_devargs.c
+++ b/drivers/net/cnxk/cnxk_ethdev_devargs.c
@@ -88,8 +88,7 @@ parse_flow_max_priority(const char *key, const char *value, void *extra_args)
val = atoi(value);
- /* Limit the max priority to 32 */
- if (val < 1 || val > 32)
+ if (val < 1 || val > ROC_NPC_MAX_MCAM_PRIORITY)
return -EINVAL;
*(uint16_t *)extra_args = val;
@@ -390,7 +389,12 @@ cnxk_ethdev_parse_devargs(struct rte_devargs *devargs, struct cnxk_eth_dev *dev)
dev->nix.meta_buf_sz = meta_buf_sz;
dev->npc.flow_prealloc_size = flow_prealloc_size;
- dev->npc.flow_max_priority = flow_max_priority;
+
+ if (roc_model_is_cn20k())
+ dev->npc.flow_max_priority = ROC_NPC_MAX_MCAM_PRIORITY;
+ else
+ dev->npc.flow_max_priority = flow_max_priority;
+
dev->npc.switch_header_type = switch_header_type;
dev->npc.sdp_channel = sdp_chan.channel;
dev->npc.sdp_channel_mask = sdp_chan.mask;
diff --git a/drivers/net/cnxk/cnxk_flow.c b/drivers/net/cnxk/cnxk_flow.c
index d3c20e8315..887dd8f911 100644
--- a/drivers/net/cnxk/cnxk_flow.c
+++ b/drivers/net/cnxk/cnxk_flow.c
@@ -990,10 +990,14 @@ cnxk_flow_query_common(struct rte_eth_dev *eth_dev, struct rte_flow *flow,
npc = &rep_dev->parent_dev->npc;
}
- if (in_flow->use_pre_alloc)
+ if (in_flow->use_pre_alloc) {
rc = roc_npc_inl_mcam_read_counter(in_flow->ctr_id, &query->hits);
- else
- rc = roc_npc_mcam_read_counter(npc, in_flow->ctr_id, &query->hits);
+ } else {
+ if (roc_model_is_cn20k())
+ rc = roc_npc_mcam_get_stats(npc, in_flow, &query->hits);
+ else
+ rc = roc_npc_mcam_read_counter(npc, in_flow->ctr_id, &query->hits);
+ }
if (rc != 0) {
errcode = EIO;
errmsg = "Error reading flow counter";
diff --git a/drivers/net/cnxk/cnxk_flow_wrapper.c b/drivers/net/cnxk/cnxk_flow_wrapper.c
new file mode 100644
index 0000000000..af2eee7266
--- /dev/null
+++ b/drivers/net/cnxk/cnxk_flow_wrapper.c
@@ -0,0 +1,303 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(C) 2024 Marvell.
+ */
+
+#ifdef CNXK_PLATFORM_CN10K
+#include "cn10k_ethdev.h"
+#include "cn10k_rx.h"
+#endif
+#ifdef CNXK_PLATFORM_CN20K
+#include "cn20k_ethdev.h"
+#include "cn20k_rx.h"
+#endif
+#include "cnxk_ethdev_mcs.h"
+#include "cnxk_flow_wrapper.h"
+#include <cnxk_flow.h>
+
+static void
+cnxk_eth_set_rx_function(struct rte_eth_dev *eth_dev)
+{
+ RTE_SET_USED(eth_dev);
+#ifdef CNXK_PLATFORM_CN10K
+ cn10k_eth_set_rx_function(eth_dev);
+#endif
+#ifdef CNXK_PLATFORM_CN20K
+ cn20k_eth_set_rx_function(eth_dev);
+#endif
+}
+
+static int
+cnxk_mtr_connect(struct rte_eth_dev *eth_dev, uint32_t mtr_id)
+{
+ return nix_mtr_connect(eth_dev, mtr_id);
+}
+
+static int
+cnxk_mtr_destroy(struct rte_eth_dev *eth_dev, uint32_t mtr_id)
+{
+ struct rte_mtr_error mtr_error;
+
+ return nix_mtr_destroy(eth_dev, mtr_id, &mtr_error);
+}
+
+static int
+cnxk_mtr_configure(struct rte_eth_dev *eth_dev, const struct rte_flow_action actions[])
+{
+ uint32_t mtr_id = 0xffff, prev_mtr_id = 0xffff, next_mtr_id = 0xffff;
+ const struct rte_flow_action_meter *mtr_conf;
+ const struct rte_flow_action_queue *q_conf;
+ const struct rte_flow_action_rss *rss_conf;
+ struct cnxk_mtr_policy_node *policy;
+ bool is_mtr_act = false;
+ int tree_level = 0;
+ int rc = -EINVAL, i;
+
+ for (i = 0; actions[i].type != RTE_FLOW_ACTION_TYPE_END; i++) {
+ if (actions[i].type == RTE_FLOW_ACTION_TYPE_METER) {
+ mtr_conf = (const struct rte_flow_action_meter *)(actions[i].conf);
+ mtr_id = mtr_conf->mtr_id;
+ is_mtr_act = true;
+ }
+ if (actions[i].type == RTE_FLOW_ACTION_TYPE_QUEUE) {
+ q_conf = (const struct rte_flow_action_queue *)(actions[i].conf);
+ if (is_mtr_act)
+ nix_mtr_rq_update(eth_dev, mtr_id, 1, &q_conf->index);
+ }
+ if (actions[i].type == RTE_FLOW_ACTION_TYPE_RSS) {
+ rss_conf = (const struct rte_flow_action_rss *)(actions[i].conf);
+ if (is_mtr_act)
+ nix_mtr_rq_update(eth_dev, mtr_id, rss_conf->queue_num,
+ rss_conf->queue);
+ }
+ }
+
+ if (!is_mtr_act)
+ return rc;
+
+ prev_mtr_id = mtr_id;
+ next_mtr_id = mtr_id;
+ while (next_mtr_id != 0xffff) {
+ rc = nix_mtr_validate(eth_dev, next_mtr_id);
+ if (rc)
+ return rc;
+
+ rc = nix_mtr_policy_act_get(eth_dev, next_mtr_id, &policy);
+ if (rc)
+ return rc;
+
+ rc = nix_mtr_color_action_validate(eth_dev, mtr_id, &prev_mtr_id, &next_mtr_id,
+ policy, &tree_level);
+ if (rc)
+ return rc;
+ }
+
+ return nix_mtr_configure(eth_dev, mtr_id);
+}
+
+static int
+cnxk_rss_action_validate(struct rte_eth_dev *eth_dev, const struct rte_flow_attr *attr,
+ const struct rte_flow_action *act)
+{
+ const struct rte_flow_action_rss *rss;
+
+ if (act == NULL)
+ return -EINVAL;
+
+ rss = (const struct rte_flow_action_rss *)act->conf;
+
+ if (attr->egress) {
+ plt_err("No support of RSS in egress");
+ return -EINVAL;
+ }
+
+ if (eth_dev->data->dev_conf.rxmode.mq_mode != RTE_ETH_MQ_RX_RSS) {
+ plt_err("multi-queue mode is disabled");
+ return -ENOTSUP;
+ }
+
+ if (!rss || !rss->queue_num) {
+ plt_err("no valid queues");
+ return -EINVAL;
+ }
+
+ if (rss->func != RTE_ETH_HASH_FUNCTION_DEFAULT) {
+ plt_err("non-default RSS hash functions are not supported");
+ return -ENOTSUP;
+ }
+
+ if (rss->key_len && rss->key_len > ROC_NIX_RSS_KEY_LEN) {
+ plt_err("RSS hash key too large");
+ return -ENOTSUP;
+ }
+
+ return 0;
+}
+
+struct rte_flow *
+cnxk_flow_create_wrapper(struct rte_eth_dev *eth_dev, const struct rte_flow_attr *attr,
+ const struct rte_flow_item pattern[],
+ const struct rte_flow_action actions[], struct rte_flow_error *error)
+{
+ struct cnxk_eth_dev *dev = cnxk_eth_pmd_priv(eth_dev);
+ const struct rte_flow_action *action_rss = NULL;
+ const struct rte_flow_action_meter *mtr = NULL;
+ const struct rte_flow_action *act_q = NULL;
+ struct roc_npc *npc = &dev->npc;
+ struct roc_npc_flow *flow;
+ void *mcs_flow = NULL;
+ int vtag_actions = 0;
+ uint32_t req_act = 0;
+ int mark_actions;
+ int i, rc;
+
+ for (i = 0; actions[i].type != RTE_FLOW_ACTION_TYPE_END; i++) {
+ if (actions[i].type == RTE_FLOW_ACTION_TYPE_METER)
+ req_act |= ROC_NPC_ACTION_TYPE_METER;
+
+ if (actions[i].type == RTE_FLOW_ACTION_TYPE_QUEUE) {
+ req_act |= ROC_NPC_ACTION_TYPE_QUEUE;
+ act_q = &actions[i];
+ }
+ if (actions[i].type == RTE_FLOW_ACTION_TYPE_RSS) {
+ req_act |= ROC_NPC_ACTION_TYPE_RSS;
+ action_rss = &actions[i];
+ }
+ }
+
+ if (req_act & ROC_NPC_ACTION_TYPE_METER) {
+ if ((req_act & ROC_NPC_ACTION_TYPE_RSS) &&
+ ((req_act & ROC_NPC_ACTION_TYPE_QUEUE))) {
+ return NULL;
+ }
+ if (req_act & ROC_NPC_ACTION_TYPE_RSS) {
+ rc = cnxk_rss_action_validate(eth_dev, attr, action_rss);
+ if (rc)
+ return NULL;
+ } else if (req_act & ROC_NPC_ACTION_TYPE_QUEUE) {
+ const struct rte_flow_action_queue *act_queue;
+ act_queue = (const struct rte_flow_action_queue *)act_q->conf;
+ if (act_queue->index > eth_dev->data->nb_rx_queues)
+ return NULL;
+ } else {
+ return NULL;
+ }
+ }
+ for (i = 0; actions[i].type != RTE_FLOW_ACTION_TYPE_END; i++) {
+ if (actions[i].type == RTE_FLOW_ACTION_TYPE_METER) {
+ mtr = (const struct rte_flow_action_meter *)actions[i].conf;
+ rc = cnxk_mtr_configure(eth_dev, actions);
+ if (rc) {
+ rte_flow_error_set(error, rc, RTE_FLOW_ERROR_TYPE_ACTION, NULL,
+ "Failed to configure mtr ");
+ return NULL;
+ }
+ break;
+ }
+ }
+
+ if (actions[0].type == RTE_FLOW_ACTION_TYPE_SECURITY &&
+ cnxk_eth_macsec_sess_get_by_sess(dev, actions[0].conf) != NULL) {
+ rc = cnxk_mcs_flow_configure(eth_dev, attr, pattern, actions, error, &mcs_flow);
+ if (rc) {
+ rte_flow_error_set(error, rc, RTE_FLOW_ERROR_TYPE_ACTION, NULL,
+ "Failed to configure mcs flow");
+ return NULL;
+ }
+ return (struct rte_flow *)mcs_flow;
+ }
+
+ flow = cnxk_flow_create(eth_dev, attr, pattern, actions, error);
+ if (!flow) {
+ if (mtr)
+ nix_mtr_chain_reset(eth_dev, mtr->mtr_id);
+
+ return NULL;
+ } else {
+ if (mtr)
+ cnxk_mtr_connect(eth_dev, mtr->mtr_id);
+ }
+
+ mark_actions = roc_npc_mark_actions_get(npc);
+ if (mark_actions) {
+ dev->rx_offload_flags |= NIX_RX_OFFLOAD_MARK_UPDATE_F;
+ cnxk_eth_set_rx_function(eth_dev);
+ }
+
+ vtag_actions = roc_npc_vtag_actions_get(npc);
+
+ if (vtag_actions) {
+ dev->rx_offload_flags |= NIX_RX_OFFLOAD_VLAN_STRIP_F;
+ cnxk_eth_set_rx_function(eth_dev);
+ }
+
+ return (struct rte_flow *)flow;
+}
+
+int
+cnxk_flow_info_get_wrapper(struct rte_eth_dev *dev, struct rte_flow_port_info *port_info,
+ struct rte_flow_queue_info *queue_info, struct rte_flow_error *err)
+{
+ RTE_SET_USED(dev);
+ RTE_SET_USED(err);
+
+ memset(port_info, 0, sizeof(*port_info));
+ memset(queue_info, 0, sizeof(*queue_info));
+
+ port_info->max_nb_counters = CNXK_NPC_COUNTERS_MAX;
+ port_info->max_nb_meters = CNXK_NIX_MTR_COUNT_MAX;
+
+ return 0;
+}
+
+int
+cnxk_flow_destroy_wrapper(struct rte_eth_dev *eth_dev, struct rte_flow *rte_flow,
+ struct rte_flow_error *error)
+{
+ struct roc_npc_flow *flow = (struct roc_npc_flow *)rte_flow;
+ struct cnxk_eth_dev *dev = cnxk_eth_pmd_priv(eth_dev);
+ struct roc_npc *npc = &dev->npc;
+ int vtag_actions = 0;
+ int mark_actions;
+ uint16_t match_id;
+ uint32_t mtr_id;
+ int rc;
+
+ match_id = (flow->npc_action >> NPC_RX_ACT_MATCH_OFFSET) & NPC_RX_ACT_MATCH_MASK;
+ if (match_id) {
+ mark_actions = roc_npc_mark_actions_sub_return(npc, 1);
+ if (mark_actions == 0) {
+ dev->rx_offload_flags &= ~NIX_RX_OFFLOAD_MARK_UPDATE_F;
+ cnxk_eth_set_rx_function(eth_dev);
+ }
+ }
+
+ vtag_actions = roc_npc_vtag_actions_get(npc);
+ if (vtag_actions) {
+ if (flow->nix_intf == ROC_NPC_INTF_RX) {
+ vtag_actions = roc_npc_vtag_actions_sub_return(npc, 1);
+ if (vtag_actions == 0) {
+ dev->rx_offload_flags &= ~NIX_RX_OFFLOAD_VLAN_STRIP_F;
+ cnxk_eth_set_rx_function(eth_dev);
+ }
+ }
+ }
+
+ if (cnxk_eth_macsec_sess_get_by_sess(dev, (void *)flow) != NULL) {
+ rc = cnxk_mcs_flow_destroy(dev, (void *)flow);
+ if (rc < 0)
+ rte_flow_error_set(error, rc, RTE_FLOW_ERROR_TYPE_UNSPECIFIED, NULL,
+ "Failed to free mcs flow");
+ return rc;
+ }
+
+ mtr_id = flow->mtr_id;
+ rc = cnxk_flow_destroy(eth_dev, flow, error);
+ if (!rc && mtr_id != ROC_NIX_MTR_ID_INVALID) {
+ rc = cnxk_mtr_destroy(eth_dev, mtr_id);
+ if (rc) {
+ rte_flow_error_set(error, ENXIO, RTE_FLOW_ERROR_TYPE_UNSPECIFIED, NULL,
+ "Meter attached to this flow does not exist");
+ }
+ }
+ return rc;
+}
diff --git a/drivers/net/cnxk/cnxk_flow_wrapper.h b/drivers/net/cnxk/cnxk_flow_wrapper.h
new file mode 100644
index 0000000000..506293dd51
--- /dev/null
+++ b/drivers/net/cnxk/cnxk_flow_wrapper.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(C) 2020 Marvell.
+ */
+#ifndef __CNXK_FLOW_WRAPPER_H__
+#define __CNXK_FLOW_WRAPPER_H__
+
+#include <rte_flow_driver.h>
+
+struct rte_flow *cnxk_flow_create_wrapper(struct rte_eth_dev *dev, const struct rte_flow_attr *attr,
+ const struct rte_flow_item pattern[],
+ const struct rte_flow_action actions[],
+ struct rte_flow_error *error);
+int cnxk_flow_destroy_wrapper(struct rte_eth_dev *dev, struct rte_flow *flow,
+ struct rte_flow_error *error);
+
+int cnxk_flow_info_get_wrapper(struct rte_eth_dev *dev, struct rte_flow_port_info *port_info,
+ struct rte_flow_queue_info *queue_info, struct rte_flow_error *err);
+
+#define CNXK_NPC_COUNTERS_MAX 512
+
+#endif /* __CNXK_FLOW_WRAPPER_H__ */
diff --git a/drivers/net/cnxk/meson.build b/drivers/net/cnxk/meson.build
index fcf48f600a..5b9e06e535 100644
--- a/drivers/net/cnxk/meson.build
+++ b/drivers/net/cnxk/meson.build
@@ -18,6 +18,13 @@ if soc_type != 'cn9k' and soc_type != 'cn10k' and soc_type != 'cn20k'
soc_type = 'all'
endif
+if soc_type == 'cn10k' or soc_type == 'all'
+ dpdk_conf.set('CNXK_PLATFORM_CN10K', 1)
+elif soc_type == 'cn20k'
+ dpdk_conf.set('CNXK_PLATFORM_CN20K', 1)
+endif
+
+
sources = files(
'cnxk_ethdev.c',
'cnxk_ethdev_cman.c',
@@ -146,9 +153,9 @@ if soc_type == 'cn10k' or soc_type == 'all'
sources += files(
'cn10k_ethdev.c',
'cn10k_ethdev_sec.c',
- 'cn10k_flow.c',
'cn10k_rx_select.c',
'cn10k_tx_select.c',
+ 'cnxk_flow_wrapper.c',
)
if host_machine.cpu_family().startswith('aarch') and not disable_template
@@ -238,6 +245,7 @@ sources += files(
'cn20k_ethdev.c',
'cn20k_rx_select.c',
'cn20k_tx_select.c',
+ 'cnxk_flow_wrapper.c',
)
if host_machine.cpu_family().startswith('aarch') and not disable_template
--
2.39.2
next prev parent reply other threads:[~2024-10-21 4:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-21 4:01 [dpdk-dev] [PATCH 1/2] common/cnxk: support NPC " psatheesh
2024-10-21 4:01 ` psatheesh [this message]
2024-10-21 17:09 ` [dpdk-dev] [PATCH 2/2] net/cnxk: support rte " Stephen Hemminger
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20241021040144.974453-2-psatheesh@marvell.com \
--to=psatheesh@marvell.com \
--cc=dev@dpdk.org \
--cc=hkalra@marvell.com \
--cc=kirankumark@marvell.com \
--cc=ndabilpuram@marvell.com \
--cc=skori@marvell.com \
--cc=skoteshwar@marvell.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).