lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Sun, 5 Apr 2020 13:42:29 -0700 From: Florian Fainelli <f.fainelli@...il.com> To: netdev <netdev@...r.kernel.org>, Andrew Lunn <andrew@...n.ch>, Vivien Didelot <vivien.didelot@...il.com>, Vladimir Oltean <olteanv@...il.com>, Ido Schimmel <idosch@...sch.org>, Jiri Pirko <jiri@...nulli.us>, Jakub Kicinski <kuba@...nel.org> Subject: Changing devlink port flavor dynamically for DSA Hi all, On a BCM7278 system, we have two ports of the switch: 5 and 8, that connect to separate Ethernet MACs that the host/CPU can control. In premise they are both interchangeable because the switch supports configuring the management port to be either 5 or 8 and the Ethernet MACs are two identical instances. The Ethernet MACs are scheduled differently across the memory controller (they have different bandwidth and priority allocations) so it is desirable to select an Ethernet MAC capable of sustaining bandwidth and latency for host networking. Our current (in the downstream kernel) use case is to expose port 5 solely as a control end-point to the user and leave it to the user how they wish to use the Ethernet MAC behind port 5. Some customers use it to bridge Wi-Fi traffic, some simply keep it disabled. Port 5 of that switch does not make use of Broadcom tags in that case, since ARL-based forwarding works just fine. The current Device Tree representation that we have for that system makes it possible for either port to be elected as the CPU port from a DSA perspective as they both have an "ethernet" phandle property that points to the appropriate Ethernet MAC node, because of that the DSA framework treats them as CPU ports. My current line of thinking is to permit a port to be configured as either "cpu" or "user" flavor and do that through devlink. This can create some challenges but hopefully this also paves the way for finally supporting "multi-CPU port" configurations. I am thinking something like this would be how I would like it to be configured: # First configure port 8 as the new CPU port devlink port set pci/0000:01:00.0/8 type cpu # Now unmap port 5 from being a CPU port devlink port set pci/0000:01:00.0/1 type eth and this would do a simple "swap" of all user ports being now associated with port 8, and no longer with port 5, thus permitting port 5 from becoming a standard user port. Or maybe, we need to do this as an atomic operation in order to avoid a switch being configured with no CPU port anymore, so something like this instead: devlink port set pci/0000:01:00.0/5 type eth mgmt pci/0000:01:00.0/8 The latter could also be used to define groups of ports within a switch that has multiple CPU ports, e.g.: # Ports 1 through 4 "bound" to CPU port 5: for i in $(seq 0 3) do devlink port set pci/0000:01:00.0/$i type eth mgmt pci/0000:01:00.0/5 done # Ports 7 bound to CPU port 8: devlink port set pci/0000:01:00.0/1 type eth mgmt pci/0000:01:00.0/8 Let me know what you think! Thanks -- Florian
Powered by blists - more mailing lists