uefi-cloud: enable SQUASHFS so the live ISO boots

[igorpecovnik]

Symptom

Booting the live UEFI ISO (from image-output-iso) built on the cloud branch fails in the initramfs:

Begin: Running /scripts/live-premount ... done.

  BOOT FAILED!
  ...
  Can not mount /dev/loop0 (/run/live/medium/live/filesystem.squashfs)
  on /run/live/rootfs/filesystem.squashfs

live-boot finds the medium and sets up the loop device, but the squashfs mount itself fails.

Root cause

The cloud UEFI kernel configs have CONFIG_BLK_DEV_LOOP=y and CONFIG_OVERLAY_FS=m but no CONFIG_SQUASHFS at all — so the kernel has no filesystem driver to read filesystem.squashfs. Every other branch (current/edge/legacy/bleedingedge) enables squashfs, which is why only cloud-branch ISOs fail. This is not a compressor mismatch — the driver is entirely absent.

image-output-iso builds the live ISO on the cloud branch (it's the branch that ships vmlinux-*), so this combination is exactly what breaks.

Fix

Enable SQUASHFS built-in (=y, so it's available regardless of initrd contents) in both linux-uefi-x86-cloud and linux-uefi-arm64-cloud, with the same compressor set as the sibling branches — including CONFIG_SQUASHFS_ZSTD=y to match image-output-iso's default -comp zstd.

CONFIG_SQUASHFS=y
CONFIG_SQUASHFS_FILE_DIRECT=y
CONFIG_SQUASHFS_CHOICE_DECOMP_BY_MOUNT=y   # x86 only (matches x86 siblings)
CONFIG_SQUASHFS_XATTR=y
CONFIG_SQUASHFS_LZ4=y
CONFIG_SQUASHFS_LZO=y
CONFIG_SQUASHFS_XZ=y
CONFIG_SQUASHFS_ZSTD=y

Test

• Build uefi-x86 BRANCH=cloud with image-output-iso, boot the ISO as a virtual CD — live system reaches userspace (squashfs mounts).

Summary by CodeRabbit

• New Features
  • Added SquashFS filesystem support for ARM64 and x86 cloud environments.
  • Enabled direct file access, extended attributes, and multiple compression formats, including LZ4, LZO, XZ, and Zstandard.
  • Added support for selecting the decompressor during mounting on x86 cloud systems.

[coderabbitai]

📝 Walkthrough

Walkthrough

Changes

SquashFS cloud kernel support

Layer / File(s)	Summary
Enable SquashFS kernel features config/kernel/linux-uefi-arm64-cloud.config, config/kernel/linux-uefi-x86-cloud.config	Both configurations enable built-in SquashFS support, direct file access, extended attributes, and LZ4, LZO, XZ, and Zstd compression support. The x86 configuration also enables mount-time decompressor selection.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Suggested reviewers: rpardini

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly states that SQUASHFS is enabled for UEFI cloud kernels so live ISOs can boot.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix-uefi-cloud-squashfs

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[EvilOlaf]

probably fine

[github-actions]

✅ This PR has been reviewed and approved — all set for merge!