From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f54.google.com (mail-wr1-f54.google.com [209.85.221.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DBC06500972 for ; Mon, 19 Jan 2026 22:48:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.54 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768862891; cv=none; b=FlXUbDQKz8KTix+KN8ZQDbjcMkRN/jSJMM37TmcQUCX2aUQtksv2hwnh9yr41OTFXPcQM/w7SbiH4zmCEgjLWFrnz/FLsj/MFNLX+la9HyQ9h8So7zOBeTd8oAP8KZqTbOwZbGEVm4Z3m3+OZk1OO4o0czmrTomOx41yF+DixsM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768862891; c=relaxed/simple; bh=bD1z/PN+x3psCjnyC4I0t+mxoFCICQGXJanx1lcbVQA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kofWEcrKJj/qJ2VGqwHt6WmGK7mCwyK7wpBl3d3LP1Yefc0yrDAtT6kbhx05kHnoVdZJ/w2CeQSDM5r2gYZ/pgveRheJODO3OCkqDBVtwtKml7khqWZQNMfpErF0uTx1KNjQ/3ms0XMKM5mhAX8/RVNVmXiFuhLkdO0kLRaBjK8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=GJlfgl9d; arc=none smtp.client-ip=209.85.221.54 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="GJlfgl9d" Received: by mail-wr1-f54.google.com with SMTP id ffacd0b85a97d-4358f854840so678f8f.3 for ; Mon, 19 Jan 2026 14:48:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1768862888; x=1769467688; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=cXT+K1cDDWllvWtcw5+dpqQq02cMP5fk/sy9EbjTNVU=; b=GJlfgl9d/fh/5DQ45vMCe03Hh9IgzrzXC/eL3GCQgBNUvDIlG+L5dyYCj2qgxGmZIk vzD7tXEBugNrnmPAINg7hg2VQLM6i6N/77aaPn0mai0XheiezRMuSbfUui+eK5RVv/aY 1PHyGBlGgbf587/KwWYQ9P8syyPRjrBd9vl75Pq5rHkmqOkELrbNEnIFMhIhUmc6+pi9 SoaAeAadDbrPm9pL4WkqsyRIGrX8rneDvdoYH3JdPbq+rcgkQl+iclsT6sjwOBNn+Wzx ZlG9ebPDb/NfsoTrBCwTedpC2PB300XLDKv+t6ASWeVhZY24sinbx3UyaFSmvdWkXoqR 9QGw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768862888; x=1769467688; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=cXT+K1cDDWllvWtcw5+dpqQq02cMP5fk/sy9EbjTNVU=; b=Gdjw4eVNrAhbK7p03S7tsS4KXFVyHYr12IU2m17q3Jp6F3gIP+SvWTg+u5mRhm+JlN zk0E8amYxSjxN6dnTAMbp4OdSwM+zLA/mq8PgoX/WZnEA3Az+Vru+TxuT/PWNxngy32w fZiK/FkXJSqE2Yj7cRjx+EqD7dLJOZuetwe4OTSaCSxi5DgjqSU2WhwXPlHI97fQIAvW 9rhQjV3Br8fWfcuFC+Xm5DHiuLRosHH+Prsqm4ioAExk8e3Tsz6AR7dUVSh+QhyzMfOj 7Im4xxV1Ci7znwUeNlkD/Tj6tnq/8vkWeeyC8DUxsT8mH2SXauan5BxQDESZgXvnERLe U73A== X-Forwarded-Encrypted: i=1; AJvYcCWUMY6mlssXXJHzHWRP8ySbj7SUr9o0zm/aRHG8avqbnGVHHkj2VA3jcEnjDbQMAQSPoAJsQSg=@vger.kernel.org X-Gm-Message-State: AOJu0YzSm9Ce+ZERcz7Sx1zogf9vr2BW8U1iXqFB8COEwwXMsDcUz3vc CG8LZixQ/opG/5LmQTsyj5v0H92ANtoit25r7r2MYZlFk+u5SCrIoXFo X-Gm-Gg: AZuq6aJ5e3pOvpPN54+2d8kVcmi7xuKbC/8M87/JWad8iKKCDchNOMqyAhDPOL0GFFM J2eOIvGN7wT79cYfyR0noKkD18/qYRpsOJ/w0R1o9Wd5i8ga/gk3KnqMVedMuNG7uESJTFWASKV aqWeopM8Y0BmRywsoAOxQDdVzqQf7Pix3qZXqaLGoFUbvWDuDyKw4yewKWYu+I1pvFZ4MYPtLBU Kg/ahaVmJCFLdzHdtFS/BKdj00N4WMP5Obky18hQKot96W48b9Y3j9xgu4gduB9phYZc4sZ6RkI jZzIgJNRiCkxr8OTpalSNsP0YCD4sxxbD7nbKyx6y+b9XNeJ/YZ6UCYM/qsvM82JJVhOY34BQgL kTbfTBAhEIvDdecJAtt4sMB4OMBJSeh+54h1dDiOvdwWKoXsxX66LHNXesob4Gn/KzNrxfo0g7d yde03d975bwdGsaw== X-Received: by 2002:a05:6000:2309:b0:430:fa9a:769 with SMTP id ffacd0b85a97d-4358b9cb703mr806308f8f.8.1768862888046; Mon, 19 Jan 2026 14:48:08 -0800 (PST) Received: from skbuf ([2a02:2f04:d501:d900:619a:24df:1726:f869]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4356996dad0sm25609148f8f.27.2026.01.19.14.48.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Jan 2026 14:48:07 -0800 (PST) Date: Tue, 20 Jan 2026 00:48:05 +0200 From: Vladimir Oltean To: Linus Walleij Cc: Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Woojung Huh , UNGLinuxDriver@microchip.com, netdev@vger.kernel.org Subject: Re: [PATCH net-next v2 4/4] net: dsa: ks8995: Implement port isolation Message-ID: <20260119224805.hjvh5xdjfhd6c6kf@skbuf> References: <20260119-ks8995-fixups-v2-0-98bd034a0d12@kernel.org> <20260119-ks8995-fixups-v2-0-98bd034a0d12@kernel.org> <20260119-ks8995-fixups-v2-4-98bd034a0d12@kernel.org> <20260119-ks8995-fixups-v2-4-98bd034a0d12@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260119-ks8995-fixups-v2-4-98bd034a0d12@kernel.org> <20260119-ks8995-fixups-v2-4-98bd034a0d12@kernel.org> On Mon, Jan 19, 2026 at 03:30:08PM +0100, Linus Walleij wrote: > It is unsound to not have proper port isolation on a > switch which supports it. > > Set each port as isolated by default in the setup callback > and de-isolate and isolate the ports in the bridge join/leave > callbacks. > > Fixes: a7fe8b266f65 ("net: dsa: ks8995: Add basic switch set-up") > Reported-by: Vladimir Oltean > Signed-off-by: Linus Walleij > --- > drivers/net/dsa/ks8995.c | 131 ++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 129 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/dsa/ks8995.c b/drivers/net/dsa/ks8995.c > index 060bc8303a14..574e14743a36 100644 > --- a/drivers/net/dsa/ks8995.c > +++ b/drivers/net/dsa/ks8995.c > @@ -80,6 +80,11 @@ > #define KS8995_PC0_TAG_REM BIT(1) /* Enable tag removal on port */ > #define KS8995_PC0_PRIO_EN BIT(0) /* Enable priority handling */ > > +#define KS8995_PC1_SNIFF_PORT BIT(7) /* This port is a sniffer port */ > +#define KS8995_PC1_RCV_SNIFF BIT(6) /* Packets received goes to sniffer port(s) */ > +#define KS8995_PC1_XMIT_SNIFF BIT(5) /* Packets transmitted goes to sniffer port(s) */ > +#define KS8995_PC1_PORT_VLAN GENMASK(4, 0) /* Port isolation mask */ > + > #define KS8995_PC2_TXEN BIT(2) /* Enable TX on port */ > #define KS8995_PC2_RXEN BIT(1) /* Enable RX on port */ > #define KS8995_PC2_LEARN_DIS BIT(0) /* Disable learning on port */ > @@ -441,6 +446,44 @@ dsa_tag_protocol ks8995_get_tag_protocol(struct dsa_switch *ds, > > static int ks8995_setup(struct dsa_switch *ds) > { > + struct ks8995_switch *ks = ds->priv; > + int ret; > + u8 val; > + int i; > + > + /* Isolate all user ports so they can only send packets to itself and the CPU port */ I would refrain from using "isolation" related terminology for user port separation, because of the naming collision with the BR_ISOLATED bridge port flag (from "man bridge", isolated bridge ports "will be able to communicate with non-isolated ports only"). > + for (i = 0; i < KS8995_CPU_PORT; i++) { > + ret = ks8995_read_reg(ks, KS8995_REG_PC(i, KS8995_REG_PC1), &val); > + if (ret) { > + dev_err(ks->dev, "failed to read KS8995_REG_PC1 on port %d\n", i); > + return ret; > + } > + > + val &= ~KS8995_PC1_PORT_VLAN; > + val |= (BIT(i) | BIT(KS8995_CPU_PORT)); > + > + ret = ks8995_write_reg(ks, KS8995_REG_PC(i, KS8995_REG_PC1), val); Do you actually need to perform a register read at probe time, or could you just call ks8995_write_reg() with known good values for the sniff port bits too? > + if (ret) { > + dev_err(ks->dev, "failed to write KS8995_REG_PC1 on port %d\n", i); > + return ret; > + } > + } > + > + /* The CPU port should be able to talk to all ports */ > + ret = ks8995_read_reg(ks, KS8995_REG_PC(KS8995_CPU_PORT, KS8995_REG_PC1), &val); > + if (ret) { > + dev_err(ks->dev, "failed to read KS8995_REG_PC1 on CPU port\n"); > + return ret; > + } > + > + val |= KS8995_PC1_PORT_VLAN; Writing this value enables hairpinning (reflection of forwarded traffic) on the CPU port, because KS8995_PC1_PORT_VLAN (GENMASK(4, 0)) includes KS8995_CPU_PORT (4). > + > + ret = ks8995_write_reg(ks, KS8995_REG_PC(KS8995_CPU_PORT, KS8995_REG_PC1), val); > + if (ret) { > + dev_err(ks->dev, "failed to write KS8995_REG_PC1 on CPU port\n"); > + return ret; > + } > + > return 0; > } > > @@ -466,8 +509,44 @@ static int ks8995_port_bridge_join(struct dsa_switch *ds, int port, > bool *tx_fwd_offload, > struct netlink_ext_ack *extack) > { > + struct ks8995_switch *ks = ds->priv; > + u8 port_bitmap = 0; > + int ret; > + u8 val; > + int i; > + > + /* De-isolate this port from any other port on the bridge */ > + port_bitmap |= BIT(port); A bit strange to unconditionally modify the initialization value of a variable rather than just assign BIT(port) as its initializer. > + for (i = 0; i < KS8995_CPU_PORT; i++) { > + if (i == port) > + continue; > + if (!dsa_port_offloads_bridge(dsa_to_port(ds, i), &bridge)) > + continue; dsa_to_port() has an embedded loop over ports inside, so actually this loop iterates ds->num_ports^2 times. It is recommended that you use the dsa_switch_for_each_user_port() iterator and that gives you "dp" directly (i becomes dp->index). > + port_bitmap |= BIT(i); > + } > + > + /* Update all affected ports with the new bitmask */ > + for (i = 0; i < KS8995_CPU_PORT; i++) { > + if (!dsa_port_offloads_bridge(dsa_to_port(ds, i), &bridge)) > + continue; > + > + ret = ks8995_read_reg(ks, KS8995_REG_PC(i, KS8995_REG_PC1), &val); > + if (ret) { > + dev_err(ks->dev, "failed to read KS8995_REG_PC1 on port %d\n", i); > + return ret; > + } > + > + val |= port_bitmap; Same hairpinning problem. When a new port joins a bridge, the existing ports start enabling forwarding to themselves as well (the port_bitmap written to port i contains BIT(i) set). > + > + ret = ks8995_write_reg(ks, KS8995_REG_PC(i, KS8995_REG_PC1), val); > + if (ret) { > + dev_err(ks->dev, "failed to write KS8995_REG_PC1 on port %d\n", i); > + return ret; > + } > + } > + > /* port_stp_state_set() will be called after to put the port in > - * appropriate state so there is no need to do anything. > + * appropriate state. > */ > > return 0; > @@ -476,8 +555,56 @@ static int ks8995_port_bridge_join(struct dsa_switch *ds, int port, > static void ks8995_port_bridge_leave(struct dsa_switch *ds, int port, > struct dsa_bridge bridge) > { > + struct ks8995_switch *ks = ds->priv; > + u8 port_bitmap = 0; > + int ret; > + u8 val; > + int i; > + > + /* Isolate this port from any other port on the bridge */ > + for (i = 0; i < KS8995_CPU_PORT; i++) { > + /* Current port handled last */ > + if (i == port) > + continue; > + /* Not on this bridge */ > + if (!dsa_port_offloads_bridge(dsa_to_port(ds, i), &bridge)) > + continue; > + > + ret = ks8995_read_reg(ks, KS8995_REG_PC(i, KS8995_REG_PC1), &val); > + if (ret) { > + dev_err(ks->dev, "failed to read KS8995_REG_PC1 on port %d\n", i); > + return; > + } > + > + val &= ~BIT(port); > + > + ret = ks8995_write_reg(ks, KS8995_REG_PC(i, KS8995_REG_PC1), val); > + if (ret) { > + dev_err(ks->dev, "failed to write KS8995_REG_PC1 on port %d\n", i); > + return; > + } > + > + /* Accumulate this port for access by current */ > + port_bitmap |= BIT(i); > + } > + > + /* Isolate this port from all other ports formerly on the bridge */ > + ret = ks8995_read_reg(ks, KS8995_REG_PC(port, KS8995_REG_PC1), &val); > + if (ret) { > + dev_err(ks->dev, "failed to read KS8995_REG_PC1 on port %d\n", port); > + return; > + } > + > + val &= ~port_bitmap; > + > + ret = ks8995_write_reg(ks, KS8995_REG_PC(port, KS8995_REG_PC1), val); > + if (ret) { > + dev_err(ks->dev, "failed to write KS8995_REG_PC1 on port %d\n", port); > + return; > + } > + The register layout seems identical with the one from ksz8_cfg_port_member(), but that being said, I don't think I have a problem with the KS8995 driver continuing to be maintained separately (for now). > /* port_stp_state_set() will be called after to put the port in > - * forwarding state so there is no need to do anything. > + * forwarding state. > */ > } > > > -- > 2.52.0 >