microsoft / microsoft/openvmm

Disable X2APIC MSR offloads when XAPIC is in use

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tdx
Dominant language
Rust
Stars
1.9k
Forks
238
Avg merge
1d 15h
Merged PRs (30d)
100

Description

When hiding isolation from the guest, we allow the guest to run in XAPIC mode. When running in this configuration, we should not enable the X2APIC MSR offloads via the MSR bitmap, but we should still allow the other vAPIC offloads.

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First steps

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  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by tracing the Rust code that configures the MSR bitmap and vAPIC offloads for guests running in XAPIC mode. The change is done when X2APIC MSR offloads are disabled in that configuration while the other vAPIC offloads remain enabled; add or update coverage if the relevant tests are found.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
operating-systems
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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