git: e3a0571ad74d - main - vtnet: expose flags via sysctl tree

The branch main has been updated by tuexen:

URL: https://cgit.FreeBSD.org/src/commit/?id=e3a0571ad74d8429a95fcae9efc1d91cc109a337

commit e3a0571ad74d8429a95fcae9efc1d91cc109a337
Author:     Michael Tuexen <tuexen@FreeBSD.org>
AuthorDate: 2025-12-18 14:42:13 +0000
Commit:     Michael Tuexen <tuexen@FreeBSD.org>
CommitDate: 2025-12-18 14:42:13 +0000

    vtnet: expose flags via sysctl tree
    
    Provide the flags used for a vtnet interface via the sysctl tree.
    This is mostly used for debugging purposes.
    
    Reviewed by:            Timo Völker
    MFC after:              1 week
    Differential Revision:  https://reviews.freebsd.org/D54283
---
 share/man/man4/vtnet.4               |  4 +++-
 sys/dev/virtio/network/if_vtnet.c    | 20 ++++++++++++++++++++
 sys/dev/virtio/network/if_vtnetvar.h |  5 +++++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/share/man/man4/vtnet.4 b/share/man/man4/vtnet.4
index fd41b36882a6..92f72030fc31 100644
--- a/share/man/man4/vtnet.4
+++ b/share/man/man4/vtnet.4
@@ -22,7 +22,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd September 30, 2025
+.Dd December 18, 2025
 .Dt VTNET 4
 .Os
 .Sh NAME
@@ -271,6 +271,8 @@ The number of active virtqueue pairs.
 The number of requested virtqueue pairs.
 .It Va dev.vtnet. Ns Ar X Ns Va .max_vq_pairs
 The maximum number of supported virtqueue pairs.
+.It Va dev.vtnet. Ns Ar X Ns Va .flags
+The flags of the interface. Mostly for debugging purposes.
 .El
 .Sh SEE ALSO
 .Xr arp 4 ,
diff --git a/sys/dev/virtio/network/if_vtnet.c b/sys/dev/virtio/network/if_vtnet.c
index d9daa5bfd70a..58cef9b34449 100644
--- a/sys/dev/virtio/network/if_vtnet.c
+++ b/sys/dev/virtio/network/if_vtnet.c
@@ -40,6 +40,7 @@
 #include <sys/mbuf.h>
 #include <sys/module.h>
 #include <sys/msan.h>
+#include <sys/sbuf.h>
 #include <sys/socket.h>
 #include <sys/sysctl.h>
 #include <sys/random.h>
@@ -4398,6 +4399,22 @@ vtnet_setup_stat_sysctl(struct sysctl_ctx_list *ctx,
 	    "Times the transmit interrupt task rescheduled itself");
 }
 
+static int
+vtnet_sysctl_flags(SYSCTL_HANDLER_ARGS)
+{
+	struct vtnet_softc *sc;
+	struct sbuf *sb;
+	int error;
+
+	sb = sbuf_new_auto();
+	sc = (struct vtnet_softc *)arg1;
+	sbuf_printf(sb, "%b", sc->vtnet_flags, VTNET_FLAGS_BITS);
+	sbuf_finish(sb);
+	error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
+	sbuf_delete(sb);
+	return (error);
+}
+
 static void
 vtnet_setup_sysctl(struct vtnet_softc *sc)
 {
@@ -4420,6 +4437,9 @@ vtnet_setup_sysctl(struct vtnet_softc *sc)
 	SYSCTL_ADD_INT(ctx, child, OID_AUTO, "act_vq_pairs",
 	    CTLFLAG_RD, &sc->vtnet_act_vq_pairs, 0,
 	    "Number of active virtqueue pairs");
+	SYSCTL_ADD_PROC(ctx, child, OID_AUTO, "flags",
+	    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, sc, 0,
+	    vtnet_sysctl_flags, "A", "Flags");
 
 	vtnet_setup_stat_sysctl(ctx, child, sc);
 }
diff --git a/sys/dev/virtio/network/if_vtnetvar.h b/sys/dev/virtio/network/if_vtnetvar.h
index cab7ced639a7..eb5e6784b07f 100644
--- a/sys/dev/virtio/network/if_vtnetvar.h
+++ b/sys/dev/virtio/network/if_vtnetvar.h
@@ -191,6 +191,11 @@ struct vtnet_softc {
 	char			 vtnet_mtx_name[16];
 	uint8_t			 vtnet_hwaddr[ETHER_ADDR_LEN];
 };
+/* vtnet flag descriptions for use with printf(9) %b identifier. */
+#define VTNET_FLAGS_BITS \
+    "\20\1MODERN\2MAC\3CTRL_VQ\4CTRL_RX\5CTRL_MAC\6VLAN_FILTER\7TSO_ECN" \
+    "\10MRG_RXBUFS\11LRO_NOMRG\12MQ\13INDIRECT\14EVENT_IDX\15SUSPENDED" \
+    "\16FIXUP_NEEDS_CSUM\17SW_LRO"
 
 static bool
 vtnet_modern(struct vtnet_softc *sc)