Merge branch 'selftests-hw-net-toeplitz-read-config-from-the-nic-directly'

Jakub Kicinski says:

====================
selftests: hw-net: toeplitz: read config from the NIC directly

First patch here tries to auto-disable building the iouring sample.
Our CI will still run the iouring test(s), of course, but it looks
like the liburing updates aren't very quick in distroes and having
to hack around it when developing unrelated tests is a bit annoying.

Remaining 4 patches iron out running the Toeplitz hash test against
real NICs. I tested mlx5, bnxt and fbnic, they all pass now.
I switched to using YNL directly in the C code, can't see a reason
to get the info in Python and pass it to C via argv. The old code
likely did this because it predates YNL.
====================

Link: https://patch.msgid.link/20251121040259.3647749-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

3 files changed, 98 insertions, 18 deletions

diff --git a/tools/testing/selftests/drivers/net/hw/Makefile b/tools/testing/selftests/drivers/net/hw/Makefile
index 1760238e9d4f..7c819fdfa107 100644
--- a/tools/testing/selftests/drivers/net/hw/Makefile
+++ b/tools/testing/selftests/drivers/net/hw/Makefile
@@ -1,8 +1,20 @@
 # SPDX-License-Identifier: GPL-2.0+ OR MIT
 
+# Check if io_uring supports zero-copy receive
+HAS_IOURING_ZCRX := $(shell \
+	echo -e '#include <liburing.h>\n' \
+	     'void *func = (void *)io_uring_register_ifq;\n' \
+	     'int main() {return 0;}' | \
+	$(CC) -luring -x c - -o /dev/null 2>&1 && echo y)
+
+ifeq ($(HAS_IOURING_ZCRX),y)
+COND_GEN_FILES += iou-zcrx
+else
+$(warning excluding iouring tests, liburing not installed or too old)
+endif
+
 TEST_GEN_FILES := \
-	iou-zcrx \
-	toeplitz \
+	$(COND_GEN_FILES) \
 # end of TEST_GEN_FILES
 
 TEST_PROGS = \
@@ -42,7 +54,10 @@ TEST_INCLUDES := \
 	#
 
 # YNL files, must be before "include ..lib.mk"
-YNL_GEN_FILES := ncdevmem
+YNL_GEN_FILES := \
+	ncdevmem \
+	toeplitz \
+# end of YNL_GEN_FILES
 TEST_GEN_FILES += $(YNL_GEN_FILES)
 TEST_GEN_FILES += $(patsubst %.c,%.o,$(wildcard *.bpf.c))
 
@@ -58,4 +73,6 @@ include ../../../net/ynl.mk
 
 include ../../../net/bpf.mk
 
+ifeq ($(HAS_IOURING_ZCRX),y)
 $(OUTPUT)/iou-zcrx: LDLIBS += -luring
+endif
diff --git a/tools/testing/selftests/drivers/net/hw/toeplitz.c b/tools/testing/selftests/drivers/net/hw/toeplitz.c
index afc5f910b006..a4d04438c313 100644
--- a/tools/testing/selftests/drivers/net/hw/toeplitz.c
+++ b/tools/testing/selftests/drivers/net/hw/toeplitz.c
@@ -52,6 +52,9 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include <ynl.h>
+#include "ethtool-user.h"
+
 #include "../../../kselftest.h"
 #include "../../../net/lib/ksft.h"
 
@@ -65,6 +68,7 @@
 #define FOUR_TUPLE_MAX_LEN	((sizeof(struct in6_addr) * 2) + (sizeof(uint16_t) * 2))
 
 #define RSS_MAX_CPUS (1 << 16)	/* real constraint is PACKET_FANOUT_MAX */
+#define RSS_MAX_INDIR	(1 << 16)
 
 #define RPS_MAX_CPUS 16UL	/* must be a power of 2 */
 
@@ -102,6 +106,8 @@ struct ring_state {
 static unsigned int rx_irq_cpus[RSS_MAX_CPUS];	/* map from rxq to cpu */
 static int rps_silo_to_cpu[RPS_MAX_CPUS];
 static unsigned char toeplitz_key[TOEPLITZ_KEY_MAX_LEN];
+static unsigned int rss_indir_tbl[RSS_MAX_INDIR];
+static unsigned int rss_indir_tbl_size;
 static struct ring_state rings[RSS_MAX_CPUS];
 
 static inline uint32_t toeplitz(const unsigned char *four_tuple,
@@ -130,7 +136,12 @@ static inline uint32_t toeplitz(const unsigned char *four_tuple,
 /* Compare computed cpu with arrival cpu from packet_fanout_cpu */
 static void verify_rss(uint32_t rx_hash, int cpu)
 {
-	int queue = rx_hash % cfg_num_queues;
+	int queue;
+
+	if (rss_indir_tbl_size)
+		queue = rss_indir_tbl[rx_hash % rss_indir_tbl_size];
+	else
+		queue = rx_hash % cfg_num_queues;
 
 	log_verbose(" rxq %d (cpu %d)", queue, rx_irq_cpus[queue]);
 	if (rx_irq_cpus[queue] != cpu) {
@@ -483,6 +494,56 @@ static void parse_rps_bitmap(const char *arg)
 			rps_silo_to_cpu[cfg_num_rps_cpus++] = i;
 }
 
+static void read_rss_dev_info_ynl(void)
+{
+	struct ethtool_rss_get_req *req;
+	struct ethtool_rss_get_rsp *rsp;
+	struct ynl_sock *ys;
+
+	ys = ynl_sock_create(&ynl_ethtool_family, NULL);
+	if (!ys)
+		error(1, errno, "ynl_sock_create failed");
+
+	req = ethtool_rss_get_req_alloc();
+	if (!req)
+		error(1, errno, "ethtool_rss_get_req_alloc failed");
+
+	ethtool_rss_get_req_set_header_dev_name(req, cfg_ifname);
+
+	rsp = ethtool_rss_get(ys, req);
+	if (!rsp)
+		error(1, ys->err.code, "YNL: %s", ys->err.msg);
+
+	if (!rsp->_len.hkey)
+		error(1, 0, "RSS key not available for %s", cfg_ifname);
+
+	if (rsp->_len.hkey < TOEPLITZ_KEY_MIN_LEN ||
+	    rsp->_len.hkey > TOEPLITZ_KEY_MAX_LEN)
+		error(1, 0, "RSS key length %u out of bounds [%u, %u]",
+		      rsp->_len.hkey, TOEPLITZ_KEY_MIN_LEN,
+		      TOEPLITZ_KEY_MAX_LEN);
+
+	memcpy(toeplitz_key, rsp->hkey, rsp->_len.hkey);
+
+	if (rsp->_count.indir > RSS_MAX_INDIR)
+		error(1, 0, "RSS indirection table too large (%u > %u)",
+		      rsp->_count.indir, RSS_MAX_INDIR);
+
+	/* If indir table not available we'll fallback to simple modulo math */
+	if (rsp->_count.indir) {
+		memcpy(rss_indir_tbl, rsp->indir,
+		       rsp->_count.indir * sizeof(rss_indir_tbl[0]));
+		rss_indir_tbl_size = rsp->_count.indir;
+
+		log_verbose("RSS indirection table size: %u\n",
+			    rss_indir_tbl_size);
+	}
+
+	ethtool_rss_get_rsp_free(rsp);
+	ethtool_rss_get_req_free(req);
+	ynl_sock_destroy(ys);
+}
+
 static void parse_opts(int argc, char **argv)
 {
 	static struct option long_options[] = {
@@ -551,7 +612,7 @@ static void parse_opts(int argc, char **argv)
 	}
 
 	if (!have_toeplitz)
-		error(1, 0, "Must supply rss key ('-k')");
+		read_rss_dev_info_ynl();
 
 	num_cpus = get_nprocs();
 	if (num_cpus > RSS_MAX_CPUS)
diff --git a/tools/testing/selftests/drivers/net/hw/toeplitz.py b/tools/testing/selftests/drivers/net/hw/toeplitz.py
index 9019a8c1ff62..d2db5ee9e358 100755
--- a/tools/testing/selftests/drivers/net/hw/toeplitz.py
+++ b/tools/testing/selftests/drivers/net/hw/toeplitz.py
@@ -17,6 +17,9 @@ from lib.py import cmd, bkg, rand_port, defer
 from lib.py import ksft_in
 from lib.py import ksft_variants, KsftNamedVariant, KsftSkipEx, KsftFailEx
 
+# "define" for the ID of the Toeplitz hash function
+ETH_RSS_HASH_TOP = 1
+
 
 def _check_rps_and_rfs_not_configured(cfg):
     """Verify that RPS is not already configured."""
@@ -34,16 +37,6 @@ def _check_rps_and_rfs_not_configured(cfg):
             raise KsftSkipEx(f"RFS already configured {rfs_file}: {val}")
 
 
-def _get_rss_key(cfg):
-    """
-    Read the RSS key from the device.
-    Return a string in the traditional %02x:%02x:%02x:.. format.
-    """
-
-    rss = cfg.ethnl.rss_get({"header": {"dev-index": cfg.ifindex}})
-    return ':'.join(f'{b:02x}' for b in rss["hkey"])
-
-
 def _get_cpu_for_irq(irq):
     with open(f"/proc/irq/{irq}/smp_affinity_list", "r",
               encoding="utf-8") as fp:
@@ -153,8 +146,18 @@ def test(cfg, proto_flag, ipver, grp):
     # Check that rxhash is enabled
     ksft_in("receive-hashing: on", cmd(f"ethtool -k {cfg.ifname}").stdout)
 
+    rss = cfg.ethnl.rss_get({"header": {"dev-index": cfg.ifindex}})
+    # Make sure NIC is configured to use Toeplitz hash, and no key xfrm.
+    if rss.get('hfunc') != ETH_RSS_HASH_TOP or rss.get('input-xfrm'):
+        cfg.ethnl.rss_set({"header": {"dev-index": cfg.ifindex},
+                           "hfunc": ETH_RSS_HASH_TOP,
+                           "input-xfrm": {}})
+        defer(cfg.ethnl.rss_set, {"header": {"dev-index": cfg.ifindex},
+                                  "hfunc": rss.get('hfunc'),
+                                  "input-xfrm": rss.get('input-xfrm', {})
+                                  })
+
     port = rand_port(socket.SOCK_DGRAM)
-    key = _get_rss_key(cfg)
 
     toeplitz_path = cfg.test_dir / "toeplitz"
     rx_cmd = [
@@ -163,8 +166,7 @@ def test(cfg, proto_flag, ipver, grp):
         proto_flag,
         "-d", str(port),
         "-i", cfg.ifname,
-        "-k", key,
-        "-T", "1000",
+        "-T", "4000",
         "-s",
         "-v"
     ]