netdevsim: add support for simultaneous driver and hw XDP

Allow netdevsim to accept driver and offload attachment of XDP
BPF programs at the same time.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

drivers/net/netdevsim/bpf.c

@@ -92,7 +92,7 @@ static const struct bpf_prog_offload_ops nsim_bpf_analyzer_ops = {
 
 static bool nsim_xdp_offload_active(struct netdevsim *ns)
 {
-	return ns->xdp_prog_mode == XDP_ATTACHED_HW;
+	return ns->xdp_hw.prog;
 }
 
 static void nsim_prog_set_loaded(struct bpf_prog *prog, bool loaded)
@@ -195,11 +195,13 @@ static int nsim_xdp_offload_prog(struct netdevsim *ns, struct netdev_bpf *bpf)
 	return nsim_bpf_offload(ns, bpf->prog, nsim_xdp_offload_active(ns));
 }
 
-static int nsim_xdp_set_prog(struct netdevsim *ns, struct netdev_bpf *bpf)
+static int
+nsim_xdp_set_prog(struct netdevsim *ns, struct netdev_bpf *bpf,
+		  struct xdp_attachment_info *xdp)
 {
 	int err;
 
-	if (!xdp_attachment_flags_ok(&ns->xdp, bpf))
+	if (!xdp_attachment_flags_ok(xdp, bpf))
 		return -EBUSY;
 
 	if (bpf->command == XDP_SETUP_PROG && !ns->bpf_xdpdrv_accept) {
@@ -217,14 +219,7 @@ static int nsim_xdp_set_prog(struct netdevsim *ns, struct netdev_bpf *bpf)
 			return err;
 	}
 
-	xdp_attachment_setup(&ns->xdp, bpf);
-
-	if (!bpf->prog)
-		ns->xdp_prog_mode = XDP_ATTACHED_NONE;
-	else if (bpf->command == XDP_SETUP_PROG)
-		ns->xdp_prog_mode = XDP_ATTACHED_DRV;
-	else
-		ns->xdp_prog_mode = XDP_ATTACHED_HW;
+	xdp_attachment_setup(xdp, bpf);
 
 	return 0;
 }
@@ -284,10 +279,6 @@ static int nsim_setup_prog_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
 		NSIM_EA(bpf->extack, "MTU too large w/ XDP enabled");
 		return -EINVAL;
 	}
-	if (nsim_xdp_offload_active(ns)) {
-		NSIM_EA(bpf->extack, "xdp offload active, can't load drv prog");
-		return -EBUSY;
-	}
 	return 0;
 }
 
@@ -561,25 +552,21 @@ int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf)
 		nsim_bpf_destroy_prog(bpf->offload.prog);
 		return 0;
 	case XDP_QUERY_PROG:
-		if (ns->xdp_prog_mode != XDP_ATTACHED_DRV)
-			return 0;
 		return xdp_attachment_query(&ns->xdp, bpf);
 	case XDP_QUERY_PROG_HW:
-		if (ns->xdp_prog_mode != XDP_ATTACHED_HW)
-			return 0;
-		return xdp_attachment_query(&ns->xdp, bpf);
+		return xdp_attachment_query(&ns->xdp_hw, bpf);
 	case XDP_SETUP_PROG:
 		err = nsim_setup_prog_checks(ns, bpf);
 		if (err)
 			return err;
 
-		return nsim_xdp_set_prog(ns, bpf);
+		return nsim_xdp_set_prog(ns, bpf, &ns->xdp);
 	case XDP_SETUP_PROG_HW:
 		err = nsim_setup_prog_hw_checks(ns, bpf);
 		if (err)
 			return err;
 
-		return nsim_xdp_set_prog(ns, bpf);
+		return nsim_xdp_set_prog(ns, bpf, &ns->xdp_hw);
 	case BPF_OFFLOAD_MAP_ALLOC:
 		if (!ns->bpf_map_accept)
 			return -EOPNOTSUPP;
@@ -635,5 +622,6 @@ void nsim_bpf_uninit(struct netdevsim *ns)
 	WARN_ON(!list_empty(&ns->bpf_bound_progs));
 	WARN_ON(!list_empty(&ns->bpf_bound_maps));
 	WARN_ON(ns->xdp.prog);
+	WARN_ON(ns->xdp_hw.prog);
 	WARN_ON(ns->bpf_offloaded);
 }

drivers/net/netdevsim/netdev.c

@@ -228,8 +228,7 @@ static int nsim_change_mtu(struct net_device *dev, int new_mtu)
 {
 	struct netdevsim *ns = netdev_priv(dev);
 
-	if (ns->xdp_prog_mode == XDP_ATTACHED_DRV &&
-	    new_mtu > NSIM_XDP_MAX_MTU)
+	if (ns->xdp.prog && new_mtu > NSIM_XDP_MAX_MTU)
 		return -EBUSY;
 
 	dev->mtu = new_mtu;

drivers/net/netdevsim/netdevsim.h

@@ -69,7 +69,7 @@ struct netdevsim {
 	u32 bpf_offloaded_id;
 
 	struct xdp_attachment_info xdp;
-	int xdp_prog_mode;
+	struct xdp_attachment_info xdp_hw;
 
 	u32 prog_id_gen;
 

tools/testing/selftests/bpf/test_offload.py

@@ -814,20 +814,12 @@ try:
          "Device parameters reported for non-offloaded program")
 
     start_test("Test XDP prog replace with bad flags...")
-    ret, _, err = sim.set_xdp(obj, "offload", force=True,
-                              fail=False, include_stderr=True)
-    fail(ret == 0, "Replaced XDP program with a program in different mode")
-    check_extack_nsim(err, "program loaded with different flags.", args)
     ret, _, err = sim.set_xdp(obj, "", force=True,
                               fail=False, include_stderr=True)
     fail(ret == 0, "Replaced XDP program with a program in different mode")
     check_extack(err, "program loaded with different flags.", args)
 
     start_test("Test XDP prog remove with bad flags...")
-    ret, _, err = sim.unset_xdp("offload", force=True,
-                                fail=False, include_stderr=True)
-    fail(ret == 0, "Removed program with a bad mode mode")
-    check_extack_nsim(err, "program loaded with different flags.", args)
     ret, _, err = sim.unset_xdp("", force=True,
                                 fail=False, include_stderr=True)
     fail(ret == 0, "Removed program with a bad mode")