[PATCH stable 0/4] net: mscc: ocelot: allow unregistered IP multicast flooding

[PATCH stable 0/4] net: mscc: ocelot: allow unregistered IP multicast flooding

[Vladimir Oltean]

This series contains 4 patches (1 for each stable branch: 4.19, 5.4, 5.10 and 5.15)
which fix 2 variations of the same problem:

- Between kernels 4.18 and 5.12, IP multicast flooding on ocelot ports
  is completely broken, both for autonomous forwarding and for local CPU
  termination. The patches for 4.19 and for 5.10 fix this.

- Between kernels 5.12 and 5.18, the flooding problem has been fixed for
  autonomously forwarded IP multicast flows via a new feature commit
  which cannot be backported, but still remains broken for local CPU
  termination. The patch for 5.15 fixes this.

After kernel 5.18, the CPU flooding problem has also been fixed via a
new feature commit which also cannot be backported. So in the current
"net" tree, both kinds of IP multicast flooding work properly, and this
is the reason why these patches target just the "stable" trees.

[PATCH stable 4.19] net: mscc: ocelot: allow unregistered IP multicast flooding

[Vladimir Oltean]

Flooding of unregistered IP multicast has been broken (both to other
switch ports and to the CPU) since the ocelot driver introduction, and
up until commit 4cf35a2b627a ("net: mscc: ocelot: fix broken IP
multicast flooding"), a bug fix for commit 421741ea5672 ("net: mscc:
ocelot: offload bridge port flags to device") from v5.12.

The driver used to set PGID_MCIPV4 and PGID_MCIPV6 to the empty port
mask (0), which made unregistered IPv4/IPv6 multicast go nowhere, and
without ever modifying that port mask at runtime.

The expectation is that such packets are treated as broadcast, and
flooded according to the forwarding domain (to the CPU if the port is
standalone, or to the CPU and other bridged ports, if under a bridge).

Since the aforementioned commit, the limitation has been lifted by
responding to SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS events emitted by the
bridge. As for host flooding, DSA synthesizes another call to
ocelot_port_bridge_flags() on the NPI port which ensures that the CPU
gets the unregistered multicast traffic it might need, for example for
smcroute to work between standalone ports.

But between v4.18 and v5.12, IP multicast flooding has remained unfixed.

Delete the inexplicable premature optimization of clearing PGID_MCIPV4
and PGID_MCIPV6 as part of the init sequence, and allow unregistered IP
multicast to be flooded freely according to the forwarding domain
established by PGID_SRC, by explicitly programming PGID_MCIPV4 and
PGID_MCIPV6 towards all physical ports plus the CPU port module.

Fixes: a556c76adc05 ("net: mscc: Add initial Ocelot switch support")
Cc: stable@kernel.org
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 drivers/net/ethernet/mscc/ocelot.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index ea30da1c53f0..a4e20a62bf8d 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1733,8 +1733,12 @@ int ocelot_init(struct ocelot *ocelot)
 	ocelot_write_rix(ocelot,
 			 ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)),
 			 ANA_PGID_PGID, PGID_MC);
-	ocelot_write_rix(ocelot, 0, ANA_PGID_PGID, PGID_MCIPV4);
-	ocelot_write_rix(ocelot, 0, ANA_PGID_PGID, PGID_MCIPV6);
+	ocelot_write_rix(ocelot,
+			 ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)),
+			 ANA_PGID_PGID, PGID_MCIPV4);
+	ocelot_write_rix(ocelot,
+			 ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)),
+			 ANA_PGID_PGID, PGID_MCIPV6);
 
 	/* CPU port Injection/Extraction configuration */
 	ocelot_write_rix(ocelot, QSYS_SWITCH_PORT_MODE_INGRESS_DROP_MODE |
-- 
2.25.1

[PATCH stable 5.10] net: mscc: ocelot: allow unregistered IP multicast flooding

[Vladimir Oltean]

Flooding of unregistered IP multicast has been broken (both to other
switch ports and to the CPU) since the ocelot driver introduction, and
up until commit 4cf35a2b627a ("net: mscc: ocelot: fix broken IP
multicast flooding"), a bug fix for commit 421741ea5672 ("net: mscc:
ocelot: offload bridge port flags to device") from v5.12.

The driver used to set PGID_MCIPV4 and PGID_MCIPV6 to the empty port
mask (0), which made unregistered IPv4/IPv6 multicast go nowhere, and
without ever modifying that port mask at runtime.

The expectation is that such packets are treated as broadcast, and
flooded according to the forwarding domain (to the CPU if the port is
standalone, or to the CPU and other bridged ports, if under a bridge).

Since the aforementioned commit, the limitation has been lifted by
responding to SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS events emitted by the
bridge. As for host flooding, DSA synthesizes another call to
ocelot_port_bridge_flags() on the NPI port which ensures that the CPU
gets the unregistered multicast traffic it might need, for example for
smcroute to work between standalone ports.

But between v4.18 and v5.12, IP multicast flooding has remained unfixed.

Delete the inexplicable premature optimization of clearing PGID_MCIPV4
and PGID_MCIPV6 as part of the init sequence, and allow unregistered IP
multicast to be flooded freely according to the forwarding domain
established by PGID_SRC, by explicitly programming PGID_MCIPV4 and
PGID_MCIPV6 towards all physical ports plus the CPU port module.

Fixes: a556c76adc05 ("net: mscc: Add initial Ocelot switch support")
Cc: stable@kernel.org
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 drivers/net/ethernet/mscc/ocelot.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index a06466ecca12..a55861ea4206 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1593,8 +1593,12 @@ int ocelot_init(struct ocelot *ocelot)
 	ocelot_write_rix(ocelot,
 			 ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)),
 			 ANA_PGID_PGID, PGID_MC);
-	ocelot_write_rix(ocelot, 0, ANA_PGID_PGID, PGID_MCIPV4);
-	ocelot_write_rix(ocelot, 0, ANA_PGID_PGID, PGID_MCIPV6);
+	ocelot_write_rix(ocelot,
+			 ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)),
+			 ANA_PGID_PGID, PGID_MCIPV4);
+	ocelot_write_rix(ocelot,
+			 ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)),
+			 ANA_PGID_PGID, PGID_MCIPV6);
 
 	/* Allow manual injection via DEVCPU_QS registers, and byte swap these
 	 * registers endianness.
-- 
2.25.1

[PATCH stable 5.15] net: mscc: ocelot: allow unregistered IP multicast flooding to CPU

[Vladimir Oltean]

Since commit 4cf35a2b627a ("net: mscc: ocelot: fix broken IP multicast
flooding") from v5.12, unregistered IP multicast flooding is
configurable in the ocelot driver for bridged ports. However, by writing
0 to the PGID_MCIPV4 and PGID_MCIPV6 port masks at initialization time,
the CPU port module, for which ocelot_port_set_mcast_flood() is not
called, will have unknown IP multicast flooding disabled.

This makes it impossible for an application such as smcroute to work
properly, since all IP multicast traffic received on a standalone port
is treated as unregistered (and dropped).

Starting with commit 7569459a52c9 ("net: dsa: manage flooding on the CPU
ports"), the limitation above has been lifted, because when standalone
ports become IFF_PROMISC or IFF_ALLMULTI, ocelot_port_set_mcast_flood()
would be called on the CPU port module, so unregistered multicast is
flooded to the CPU on an as-needed basis.

But between v5.12 and v5.18, IP multicast flooding to the CPU has
remained broken, promiscuous or not.

Delete the inexplicable premature optimization of clearing PGID_MCIPV4
and PGID_MCIPV6 as part of the init sequence, and allow unregistered IP
multicast to be flooded freely to the CPU port module.

Fixes: a556c76adc05 ("net: mscc: Add initial Ocelot switch support")
Cc: stable@kernel.org
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 drivers/net/ethernet/mscc/ocelot.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index a59300d9e000..96b1e394a397 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -2206,11 +2206,15 @@ int ocelot_init(struct ocelot *ocelot)
 	ocelot_rmw_rix(ocelot, ANA_PGID_PGID_PGID(BIT(ocelot->num_phys_ports)),
 		       ANA_PGID_PGID_PGID(BIT(ocelot->num_phys_ports)),
 		       ANA_PGID_PGID, PGID_MC);
+	ocelot_rmw_rix(ocelot, ANA_PGID_PGID_PGID(BIT(ocelot->num_phys_ports)),
+		       ANA_PGID_PGID_PGID(BIT(ocelot->num_phys_ports)),
+		       ANA_PGID_PGID, PGID_MCIPV4);
+	ocelot_rmw_rix(ocelot, ANA_PGID_PGID_PGID(BIT(ocelot->num_phys_ports)),
+		       ANA_PGID_PGID_PGID(BIT(ocelot->num_phys_ports)),
+		       ANA_PGID_PGID, PGID_MCIPV6);
 	ocelot_rmw_rix(ocelot, ANA_PGID_PGID_PGID(BIT(ocelot->num_phys_ports)),
 		       ANA_PGID_PGID_PGID(BIT(ocelot->num_phys_ports)),
 		       ANA_PGID_PGID, PGID_BC);
-	ocelot_write_rix(ocelot, 0, ANA_PGID_PGID, PGID_MCIPV4);
-	ocelot_write_rix(ocelot, 0, ANA_PGID_PGID, PGID_MCIPV6);
 
 	/* Allow manual injection via DEVCPU_QS registers, and byte swap these
 	 * registers endianness.
-- 
2.25.1

[PATCH stable 5.4] net: mscc: ocelot: allow unregistered IP multicast flooding

[Vladimir Oltean]

Flooding of unregistered IP multicast has been broken (both to other
switch ports and to the CPU) since the ocelot driver introduction, and
up until commit 4cf35a2b627a ("net: mscc: ocelot: fix broken IP
multicast flooding"), a bug fix for commit 421741ea5672 ("net: mscc:
ocelot: offload bridge port flags to device") from v5.12.

The driver used to set PGID_MCIPV4 and PGID_MCIPV6 to the empty port
mask (0), which made unregistered IPv4/IPv6 multicast go nowhere, and
without ever modifying that port mask at runtime.

The expectation is that such packets are treated as broadcast, and
flooded according to the forwarding domain (to the CPU if the port is
standalone, or to the CPU and other bridged ports, if under a bridge).

Since the aforementioned commit, the limitation has been lifted by
responding to SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS events emitted by the
bridge. As for host flooding, DSA synthesizes another call to
ocelot_port_bridge_flags() on the NPI port which ensures that the CPU
gets the unregistered multicast traffic it might need, for example for
smcroute to work between standalone ports.

But between v4.18 and v5.12, IP multicast flooding has remained unfixed.

Delete the inexplicable premature optimization of clearing PGID_MCIPV4
and PGID_MCIPV6 as part of the init sequence, and allow unregistered IP
multicast to be flooded freely according to the forwarding domain
established by PGID_SRC, by explicitly programming PGID_MCIPV4 and
PGID_MCIPV6 towards all physical ports plus the CPU port module.

Fixes: a556c76adc05 ("net: mscc: Add initial Ocelot switch support")
Cc: stable@kernel.org
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 drivers/net/ethernet/mscc/ocelot.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index bf7832b34a00..acddb3aa53de 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -2153,8 +2153,12 @@ int ocelot_init(struct ocelot *ocelot)
 	ocelot_write_rix(ocelot,
 			 ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)),
 			 ANA_PGID_PGID, PGID_MC);
-	ocelot_write_rix(ocelot, 0, ANA_PGID_PGID, PGID_MCIPV4);
-	ocelot_write_rix(ocelot, 0, ANA_PGID_PGID, PGID_MCIPV6);
+	ocelot_write_rix(ocelot,
+			 ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)),
+			 ANA_PGID_PGID, PGID_MCIPV4);
+	ocelot_write_rix(ocelot,
+			 ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)),
+			 ANA_PGID_PGID, PGID_MCIPV6);
 
 	/* CPU port Injection/Extraction configuration */
 	ocelot_write_rix(ocelot, QSYS_SWITCH_PORT_MODE_INGRESS_DROP_MODE |
-- 
2.25.1

Re: [PATCH stable 0/4] net: mscc: ocelot: allow unregistered IP multicast flooding

[Greg Kroah-Hartman]

On Tue, Jun 28, 2022 at 08:20:12PM +0300, Vladimir Oltean wrote:
> This series contains 4 patches (1 for each stable branch: 4.19, 5.4, 5.10 and 5.15)
> which fix 2 variations of the same problem:
> 
> - Between kernels 4.18 and 5.12, IP multicast flooding on ocelot ports
>   is completely broken, both for autonomous forwarding and for local CPU
>   termination. The patches for 4.19 and for 5.10 fix this.
> 
> - Between kernels 5.12 and 5.18, the flooding problem has been fixed for
>   autonomously forwarded IP multicast flows via a new feature commit
>   which cannot be backported, but still remains broken for local CPU
>   termination. The patch for 5.15 fixes this.
> 
> After kernel 5.18, the CPU flooding problem has also been fixed via a
> new feature commit which also cannot be backported. So in the current
> "net" tree, both kinds of IP multicast flooding work properly, and this
> is the reason why these patches target just the "stable" trees.

All now queued up, thanks.

greg k-h