FYI - this can be pre-tested to work against PPA [1]. I'd be very happy if one could a) do that test if it is sufficient b) dump the steps to test here then so that we can complete the SRU template to get things started
[1]: https://launchpad.net/~paelzer/+archive/ubuntu/bug-1838939-rdma- azure-mlx4 ** Description changed: [Impact] - * Azure RDMA devices are driven by MLX4 driver (which I assume those - devices are derived from). + * Azure RDMA devices can be a "Network Direct" version of the MLX + InfiniBand card that is exposed to the guest and they need to be + handled by the MLX4 driver. But to be enabled properly the system needs to detect them as such. That was added in rdma-core v20 hence being fix released in >=Disco. * Fix [1] is just a new alias to detect the card as what it is. [Test Case] * TBD: Try to use rdma on "Microsoft Azure RDMA device". It would be great if someone could add some real content here. [Regression Potential] * a) The regression potential should be minimal. Existing systems either already match the HCA table or they don't (neither before nor after the fix. An issue I could think of is if there are devices that announce as vmbus:3daf2e8ca732094bab99bd1f1c86b501 but are NOT in fact this device type - they would then run into issues. * b) Of course the fix will "enable rdma support on some more devices" if someone had those devices attached but didn't use/configure them they might now initialize a bit further. But that isn't an issue and especially in cloud environments where HW config is just a click away no one usually pays for extra devices without using them. - * c) I happen to know that for DPDK usage of these devices several fixes - in later rdma-core are preferred or even needed. I'm not sure about the - usage in this case - but enabling could expose those issues which - formerly were hidden behind the "not supported" misdetection of the - card. + * c) I happen to know that for DPDK usage of these devices several fixes + in later rdma-core are preferred or even needed. I'm not sure about the + usage in this case - but enabling could expose those issues which + formerly were hidden behind the "not supported" misdetection of the + card. - For B) and C) I'd want Microsoft to ack and test this from a PPA and do + For B) and C) I'd want Microsoft to ack and test this from a PPA and do the verification on this - to be not only ok for this but for for Azure in general. [Other Info] * This falls under the SRU exception of "other safe cases" for "For Long Term Support releases we regularly want to enable new hardware". New modaliases are explicitly listed there as cases for this. + * This is reported to work in 16.04, but not as a classic "this commit + broke it regression". Back then the world of rdma/infiniband just + worked totally different as it was before the big revamp into rdma-core + never the less one could see that (abstract, not caring about details) + as an update-regression when going 16.04 to 18.04. + [1]: https://github.com/linux-rdma/rdma- core/commit/b98397f3068a42e7d8e67d4ef2a90393b4c4f08a -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1838939 Title: Add alias to support Microsoft Azure RDMA device via MLX4 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/rdma-core/+bug/1838939/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
