From 25b2999485f6cf8938f5e1baeb88b302cd420bf3 Mon Sep 17 00:00:00 2001
From: Pim van Pelt <pim@ipng.nl>
Date: Mon, 1 Apr 2024 23:04:45 +0200
Subject: [PATCH] Backport https://gerrit.fd.io/r/c/vpp/+/40441

---
 lcpng.c           | 22 ++++++++++++++++++++++
 lcpng.h           | 10 +++++++++-
 lcpng_interface.c | 11 +++++++++--
 3 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/lcpng.c b/lcpng.c
index 7e8d617..d3422f6 100644
--- a/lcpng.c
+++ b/lcpng.c
@@ -131,6 +131,28 @@ lcp_auto_subint (void)
   return lcpm->lcp_auto_subint;
 }
 
+void
+lcp_set_default_num_queues (u16 num_queues, u8 is_tx)
+{
+  lcp_main_t *lcpm = &lcp_main;
+
+  if (is_tx)
+    lcpm->num_tx_queues = num_queues;
+  else
+    lcpm->num_rx_queues = num_queues;
+}
+
+u16
+lcp_get_default_num_queues (u8 is_tx)
+{
+  lcp_main_t *lcpm = &lcp_main;
+
+  if (is_tx)
+    return lcpm->num_tx_queues;
+
+  return lcpm->num_rx_queues ?: vlib_num_workers ();
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *
diff --git a/lcpng.h b/lcpng.h
index 2447433..2fd8e91 100644
--- a/lcpng.h
+++ b/lcpng.h
@@ -27,6 +27,8 @@ typedef struct lcp_main_s
   u8 lcp_auto_subint; /* Automatically create/delete LCP sub-interfaces */
   u8 lcp_sync;	      /* Automatically sync VPP changes to LCP */
   u8 lcp_sync_unnumbered; /* Automatically sync unnumbered interfaces to LCP */
+  u16 num_rx_queues;
+  u16 num_tx_queues;
   /* Set when Unit testing */
   u8 test_mode;
 } lcp_main_t;
@@ -40,11 +42,17 @@ int lcp_set_default_ns (u8 *ns);
 u8 *lcp_get_default_ns (void); /* Returns NULL or shared string */
 int lcp_get_default_ns_fd (void);
 
-/*
+/**
  * Sync state from VPP into all LCP devices
  */
 void lcp_itf_pair_sync_state_all ();
 
+/**
+ * Get/Set the default queue number for LCP host taps.
+ */
+void lcp_set_default_num_queues (u16 num_queues, u8 is_tx);
+u16 lcp_get_default_num_queues (u8 is_tx);
+
 #endif
 
 /*
diff --git a/lcpng_interface.c b/lcpng_interface.c
index ac6f6d7..c1edb65 100644
--- a/lcpng_interface.c
+++ b/lcpng_interface.c
@@ -552,6 +552,7 @@ static clib_error_t *
 lcp_itf_pair_config (vlib_main_t *vm, unformat_input_t *input)
 {
   u8 *default_ns;
+  u32 tmp;
 
   default_ns = NULL;
 
@@ -571,6 +572,10 @@ lcp_itf_pair_config (vlib_main_t *vm, unformat_input_t *input)
 	lcp_set_auto_subint (1 /* is_auto */);
       else if (unformat (input, "lcp-sync"))
 	lcp_set_sync (1 /* is_auto */);
+      else if (unformat (input, "num-rx-queues %d", &tmp))
+	lcp_set_default_num_queues (tmp, 0 /* is_tx */);
+      else if (unformat (input, "num-tx-queues %d", &tmp))
+	lcp_set_default_num_queues (tmp, 1 /* is_tx */);
       else
 	return clib_error_return (0, "unknown input `%U'",
 				  format_unformat_error, input);
@@ -993,8 +998,10 @@ lcp_itf_pair_create (u32 phy_sw_if_index, u8 *host_if_name,
   else
     {
       tap_create_if_args_t args = {
-	.num_rx_queues = clib_max (1, vlib_num_workers ()),
-	.num_tx_queues = 1,
+	.num_rx_queues =
+	  clib_max (1, lcp_get_default_num_queues (0 /* is_tx */)),
+	.num_tx_queues =
+	  clib_max (1, lcp_get_default_num_queues (1 /* is_tx */)),
 	.id = ~0,
 	.sw_if_index = ~0,
 	.rx_ring_sz = 256,