kernel-mshv and kernel-uvm: upgrade to 6.18

[Saul Paredes (Redent0r)]

Upgrade:

• kernel-mshv to https://github.com/microsoft/CBL-Mariner-Linux-Kernel/releases/tag/rolling-lts%2Fkata%2F6.18.34.mshv3
• kernel-uvm to https://github.com/microsoft/CBL-Mariner-Linux-Kernel/releases/tag/rolling-lts%2Fkata-uvm%2F6.18.52.mshv1

Validation:

• bb: https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1218305&view=results
• image build: https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1218416&view=results
• conformance: https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1218549&view=results [1 known failure due to slighly bigger kernel size, test will be adjusted]
• conformance(kata-v2): https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1218552&view=results [known failures due to empty dir limitations in SR. Will be skipped and later fixed]
• performance: https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1219143&view=results [1 new regression in one scenario in kata-kvm. Not blocking upgrade for this and skipping for now until it's investigated]

[Copilot]

🟡 Changes recommended

The test patch reintroduces documented vPCI interrupt lifecycle, INTx reporting, and affinity regressions.

3 open findings

• Preserve MSI entries and unmap them during retarget or teardown · New
• Preserve PCI_INTERRUPT_PIN masking for legacy INTx reads · New
• Avoid prohibiting IRQ affinity changes after retargeting fix · New

What changed in this PR

Upgrades the MSHV and UVM kernels to 6.18 and refreshes packaging metadata and configurations.

Changes:

• Updates kernel versions, signatures, and manifests.
• Refreshes x86_64 and ARM64 UVM configurations.
• Adds an MSHV test patch reverting interrupt behavior.

File	Description
SPECS/​kernel-uvm/​kernel-uvm.spec	Updates UVM to 6.18.52.mshv1.
SPECS/​kernel-uvm/​kernel-uvm.signatures.json	Refreshes UVM source hashes.
SPECS/​kernel-uvm/​config_aarch64	Updates ARM64 configuration.
SPECS/​kernel-uvm/​config	Updates x86_64 configuration.
SPECS/​kernel-mshv/​kernel-mshv.spec	Updates MSHV and applies the test patch.
SPECS/​kernel-mshv/​kernel-mshv.signatures.json	Refreshes MSHV source hashes.
SPECS/​kernel-mshv/​0001-TEST-restore-mshv1-x86-vPCI-interrupt-implementation.patch	Reverts several vPCI interrupt fixes.
SPECS-SIGNED/​kernel-mshv-signed/​kernel-mshv-signed.spec	Aligns signed-kernel version metadata.
cgmanifest.json	Updates component versions and source URLs.

🧠 Review effort: Balanced

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[Copilot]

🔵 Needs a closer look

Low-level interrupt changes and acknowledged conformance and performance regressions require final human review.

0 open findings

3 resolved since last review

• Preserve MSI entries and unmap them during retarget or teardown
• Avoid prohibiting IRQ affinity changes after retargeting fix
• Preserve PCI_INTERRUPT_PIN masking for legacy INTx reads

🧠 Review effort: Balanced