Enable multicast in the "kvm" kernels

[Slawek Kaplonski]

I work in the OpenStack Neutron project and recently I wanted to optimize our CI scenario jobs by using Ubuntu minimal image as guest image for some tests (see patch https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/813195)
Unfortunately it seems that there is problem with one multicast scenario test while using ubuntu-minimal image (https://cloud-images.ubuntu.com/minimal/releases/focal/release/ubuntu-20.04-minimal-cloudimg-amd64.img). The problem is that VM booted from that image don't subscribes properly to the IGMP multicast group thus test is failing.
All works fine when image https://cloud-images.ubuntu.com/focal/current/focal-server-cloudimg-amd64.img is used in the same test.

The problem is that in the minimal image kernel linux-image-kvm (vs. linux-image-generic in the "regular" cloud image) and that "-kvm" image has disabled MULTICAST:

# CONFIG_IP_MULTICAST is not set

Would it be maybe possible to enable this option in the kernel used in the "minimal" cloud images?

[John Chittum (jchittum)]

Thanks for opening this. We'll take this to the kernel team as well.

For completeness, do you want us to investigate this on all currently support KVM kernels and images?

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-kvm/5.4.0-1051.53 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-focal' to 'verification-done-focal'. If the problem still exists, change the tag 'verification-needed-focal' to 'verification-failed-focal'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Kelsey Steele (kelsey-steele)]

verified CONFIG_IP_MULTICAST is enabled on focal/kvm in proposed. switching verification testing to done.

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux-kvm - 5.4.0-1051.53

---------------
linux-kvm (5.4.0-1051.53) focal; urgency=medium

  * focal/linux-kvm: 5.4.0-1051.53 -proposed tracker (LP: #1952303)

  * Support builtin revoked certificates (LP: #1932029)
    - [Config] kvm: Configure CONFIG_SYSTEM_REVOCATION_KEYS with revoked keys

  * Re-enable DEBUG_INFO_BTF where it was disabled (LP: #1945632)
    - [Config] kvm: Enable CONFIG_DEBUG_INFO_BTF on all arches

  * Packaging resync (LP: #1786013)
    - [Packaging] update Ubuntu.md

  * Enable multicast in the "kvm" kernels (LP: #1946672)
    - [config] Enable CONFIG_IP_MULTICAST

  [ Ubuntu: 5.4.0-92.103 ]

  * focal/linux: 5.4.0-92.103 -proposed tracker (LP: #1952316)
  * Packaging resync (LP: #1786013)
    - [Packaging] resync update-dkms-versions helper
    - debian/dkms-versions -- update from kernel-versions (main/2021.11.29)
  * CVE-2021-4002
    - tlb: mmu_gather: add tlb_flush_*_range APIs
    - hugetlbfs: flush TLBs correctly after huge_pmd_unshare
  * Re-enable DEBUG_INFO_BTF where it was disabled (LP: #1945632)
    - [Config] Enable CONFIG_DEBUG_INFO_BTF on all arches
  * Focal linux-azure: Vm crash on Dv5/Ev5 (LP: #1950462)
    - KVM: VMX: eVMCS: make evmcs_sanitize_exec_ctrls() work again
    - jump_label: Fix usage in module __init
  * Support builtin revoked certificates (LP: #1932029)
    - Revert "UBUNTU: SAUCE: (lockdown) Make get_cert_list() not complain about
      cert lists that aren't present."
    - integrity: Move import of MokListRT certs to a separate routine
    - integrity: Load certs from the EFI MOK config table
    - certs: Add ability to preload revocation certs
    - integrity: Load mokx variables into the blacklist keyring
    - certs: add 'x509_revocation_list' to gitignore
    - SAUCE: Dump stack when X.509 certificates cannot be loaded
    - [Packaging] build canonical-revoked-certs.pem from branch/arch certs
    - [Packaging] Revoke 2012 UEFI signing certificate as built-in
    - [Config] Configure CONFIG_SYSTEM_REVOCATION_KEYS with revoked keys
  * Support importing mokx keys into revocation list from the mok table
    (LP: #1928679)
    - efi: Support for MOK variable config table
    - efi: mokvar-table: fix some issues in new code
    - efi: mokvar: add missing include of asm/early_ioremap.h
    - efi/mokvar: Reserve the table only if it is in boot services data
    - SAUCE: integrity: add informational messages when revoking certs
  * Support importing mokx keys into revocation list from the mok table
    (LP: #1928679) // CVE-2020-26541 when certificates are revoked via
    MokListXRT.
    - SAUCE: integrity: Load mokx certs from the EFI MOK config table
  * Focal update: v5.4.157 upstream stable release (LP: #1951883)
    - ARM: 9133/1: mm: proc-macros: ensure *_tlb_fns are 4B aligned
    - ARM: 9134/1: remove duplicate memcpy() definition
    - ARM: 9139/1: kprobes: fix arch_init_kprobes() prototype
    - ARM: 9141/1: only warn about XIP address when not compile testing
    - ipv6: use siphash in rt6_exception_hash()
    - ipv4: use siphash instead of Jenkins in fnhe_hashfun()
    - usbnet: sanity check for maxpacket
    - usbnet: fix error return code...