Merge branch 'virtio-net-disable-delayed-refill-when-pausing-rx'

Bui Quang Minh says:

====================
virtio-net: disable delayed refill when pausing rx

Hi everyone,

This only includes the selftest for virtio-net deadlock bug. The fix
commit has been applied already.

Link: https://lore.kernel.org/virtualization/174537302875.2111809.8543884098526067319.git-patchwork-notify@kernel.org/T/
====================

Link: https://patch.msgid.link/20250425071018.36078-1-minhquangbui99@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/drivers/net/.gitignore

@@ -1,3 +1,2 @@
 # SPDX-License-Identifier: GPL-2.0-only
 napi_id_helper
-xdp_helper

tools/testing/selftests/drivers/net/Makefile

@@ -8,7 +8,6 @@ TEST_INCLUDES := $(wildcard lib/py/*.py) \
 
 TEST_GEN_FILES := \
 	napi_id_helper \
-	xdp_helper \
 # end of TEST_GEN_FILES
 
 TEST_PROGS := \

tools/testing/selftests/drivers/net/hw/Makefile

@@ -21,6 +21,7 @@ TEST_PROGS = \
 	rss_ctx.py \
 	rss_input_xfrm.py \
 	tso.py \
+	xsk_reconfig.py \
 	#
 
 TEST_FILES := \

tools/testing/selftests/drivers/net/hw/xsk_reconfig.py

@@ -0,0 +1,60 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+# This is intended to be run on a virtio-net guest interface.
+# The test binds the XDP socket to the interface without setting
+# the fill ring to trigger delayed refill_work. This helps to
+# make it easier to reproduce the deadlock when XDP program,
+# XDP socket bind/unbind, rx ring resize race with refill_work on
+# the buggy kernel.
+#
+# The Qemu command to setup virtio-net
+# -netdev tap,id=hostnet1,vhost=on,script=no,downscript=no
+# -device virtio-net-pci,netdev=hostnet1,iommu_platform=on,disable-legacy=on
+
+from lib.py import ksft_exit, ksft_run
+from lib.py import KsftSkipEx, KsftFailEx
+from lib.py import NetDrvEnv
+from lib.py import bkg, ip, cmd, ethtool
+import time
+
+def _get_rx_ring_entries(cfg):
+    output = ethtool(f"-g {cfg.ifname}", json=True)
+    return output[0]["rx"]
+
+def setup_xsk(cfg, xdp_queue_id = 0) -> bkg:
+    # Probe for support
+    xdp = cmd(f'{cfg.net_lib_dir / "xdp_helper"} - -', fail=False)
+    if xdp.ret == 255:
+        raise KsftSkipEx('AF_XDP unsupported')
+    elif xdp.ret > 0:
+        raise KsftFailEx('unable to create AF_XDP socket')
+
+    try:
+        return bkg(f'{cfg.net_lib_dir / "xdp_helper"} {cfg.ifindex} ' \
+                   '{xdp_queue_id} -z', ksft_wait=3)
+    except:
+        raise KsftSkipEx('Failed to bind XDP socket in zerocopy.\n' \
+                         'Please consider adding iommu_platform=on ' \
+                         'when setting up virtio-net-pci')
+
+def check_xdp_bind(cfg):
+    with setup_xsk(cfg):
+        ip(f"link set dev %s xdp obj %s sec xdp" %
+           (cfg.ifname, cfg.net_lib_dir / "xdp_dummy.bpf.o"))
+        ip(f"link set dev %s xdp off" % cfg.ifname)
+
+def check_rx_resize(cfg):
+    with setup_xsk(cfg):
+        rx_ring = _get_rx_ring_entries(cfg)
+        ethtool(f"-G %s rx %d" % (cfg.ifname, rx_ring // 2))
+        ethtool(f"-G %s rx %d" % (cfg.ifname, rx_ring))
+
+def main():
+    with NetDrvEnv(__file__, nsim_test=False) as cfg:
+        ksft_run([check_xdp_bind, check_rx_resize],
+                 args=(cfg, ))
+    ksft_exit()
+
+if __name__ == "__main__":
+    main()

tools/testing/selftests/drivers/net/napi_id_helper.c

@@ -8,7 +8,7 @@
 #include <arpa/inet.h>
 #include <sys/socket.h>
 
-#include "ksft.h"
+#include "../../net/lib/ksft.h"
 
 int main(int argc, char *argv[])
 {

tools/testing/selftests/drivers/net/queues.py

@@ -26,13 +26,13 @@ def nl_get_queues(cfg, nl, qtype='rx'):
 
 def check_xsk(cfg, nl, xdp_queue_id=0) -> None:
     # Probe for support
-    xdp = cmd(f'{cfg.test_dir / "xdp_helper"} - -', fail=False)
+    xdp = cmd(f'{cfg.net_lib_dir / "xdp_helper"} - -', fail=False)
     if xdp.ret == 255:
         raise KsftSkipEx('AF_XDP unsupported')
     elif xdp.ret > 0:
         raise KsftFailEx('unable to create AF_XDP socket')
 
-    with bkg(f'{cfg.test_dir / "xdp_helper"} {cfg.ifindex} {xdp_queue_id}',
+    with bkg(f'{cfg.net_lib_dir / "xdp_helper"} {cfg.ifindex} {xdp_queue_id}',
              ksft_wait=3):
 
         rx = tx = False

tools/testing/selftests/net/lib/.gitignore

@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
 csum
+xdp_helper

tools/testing/selftests/net/lib/Makefile

@@ -10,6 +10,7 @@ TEST_FILES += ../../../../net/ynl
 
 TEST_GEN_FILES += csum
 TEST_GEN_FILES += $(patsubst %.c,%.o,$(wildcard *.bpf.c))
+TEST_GEN_FILES += xdp_helper
 
 TEST_INCLUDES := $(wildcard py/*.py sh/*.sh)
 

tools/testing/selftests/net/lib/xdp_helper.c

@@ -17,6 +17,12 @@
 #define NUM_DESC (UMEM_SZ / 2048)
 
 
+static void print_usage(const char *bin)
+{
+	fprintf(stderr, "Usage: %s ifindex queue_id [-z]\n\n"
+		"where:\n\t-z: force zerocopy mode", bin);
+}
+
 /* this is a simple helper program that creates an XDP socket and does the
  * minimum necessary to get bind() to succeed.
  *
@@ -32,12 +38,13 @@ int main(int argc, char **argv)
 	struct sockaddr_xdp sxdp = { 0 };
 	int num_desc = NUM_DESC;
 	void *umem_area;
+	int retry = 0;
 	int ifindex;
 	int sock_fd;
 	int queue;
 
-	if (argc != 3) {
-		fprintf(stderr, "Usage: %s ifindex queue_id\n", argv[0]);
+	if (argc != 3 && argc != 4) {
+		print_usage(argv[0]);
 		return 1;
 	}
 
@@ -87,11 +94,29 @@ int main(int argc, char **argv)
 	sxdp.sxdp_queue_id = queue;
 	sxdp.sxdp_flags = 0;
 
-	if (bind(sock_fd, (struct sockaddr *)&sxdp, sizeof(sxdp)) != 0) {
-		munmap(umem_area, UMEM_SZ);
-		perror("bind failed");
-		close(sock_fd);
-		return 1;
+	if (argc > 3) {
+		if (!strcmp(argv[3], "-z")) {
+			sxdp.sxdp_flags = XDP_ZEROCOPY;
+		} else {
+			print_usage(argv[0]);
+			return 1;
+		}
+	}
+
+	while (1) {
+		if (bind(sock_fd, (struct sockaddr *)&sxdp, sizeof(sxdp)) == 0)
+			break;
+
+		if (errno == EBUSY && retry < 3) {
+			retry++;
+			sleep(1);
+			continue;
+		} else {
+			perror("bind failed");
+			munmap(umem_area, UMEM_SZ);
+			close(sock_fd);
+			return 1;
+		}
 	}
 
 	ksft_ready();