tdisp: Add OpenHCL and host TDISP crates #2069
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Pull Request Overview
This PR introduces the TDISP (Confidential VM Device Attestation + Encryption) framework by adding new crates that implement the host-guest communication protocol and device state management. This is part of a larger effort to merge TDISP prototype code into the main codebase.
- Adds foundational TDISP types, serialization, and device state machine for secure device attestation
- Introduces OpenHCL client interfaces for TDISP-capable devices in guest partitions
- Establishes the shared communication protocol between host and guest for device assignment flows
Reviewed Changes
Copilot reviewed 9 out of 10 changed files in this pull request and generated 5 comments.
Show a summary per file
| File | Description |
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| vm/devices/tdisp/src/lib.rs | Core TDISP implementation with state machine, host device interfaces, and operation error handling |
| vm/devices/tdisp/src/serialize.rs | Serialization/deserialization for guest-to-host command and response packets |
| vm/devices/tdisp/src/devicereport.rs | Device report types and TDI interface report parsing for attestation |
| vm/devices/tdisp/src/command.rs | Command and response structures for the guest-to-host TDISP protocol |
| vm/devices/tdisp/Cargo.toml | Cargo configuration for the core TDISP device crate |
| openhcl/openhcl_tdisp/src/lib.rs | OpenHCL client device traits for TDISP communication in guest partitions |
| openhcl/openhcl_tdisp/Cargo.toml | Cargo configuration for the OpenHCL TDISP client crate |
| openhcl/underhill_core/Cargo.toml | Adds TDISP dependencies to OpenHCL core |
| Cargo.toml | Registers new TDISP crates in workspace |
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| /// Represents a TDISP device assigned to a guest partition that can be used to | ||
| /// send TDISP commands to the host through a backing interface. | ||
| pub trait VpciTdispInterface: Send + Sync { |
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Can all these functions just be async instead of doing manual impl Futures?
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Thanks for the quick jump on this PR :)
I was recommended to use impl Future for traits instead of async by rust_analyzer. I believe this has to do with the way that async needs to express itself in traits vs. its implementations. I do not really understand it further than that.
vm/devices/tdisp/src/devicereport.rs
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| impl From<u32> for TdispDeviceReportType { |
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Again this feels like it should just be an open enum
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I will go back through and fix these, this was written before I knew about open_enum :)
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I converted each of the old enums into the open_enum style, seems to have cleaned up a lot of the serialization considerably. The only concern I have is that because open_enum is designed to allow any discriminate value in the u64 range, this now means that match{} statements which consume it do not error out when new enum types are added to the enum. For example, if I add a new command id type, I'd expect other code that handles that to now explicitly handle the new Id in their match branches, but this now doesn't happen with open_enum. Is there a solution to this problem or am I misunderstanding something?
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… convert to and from an Error, is this okay?)
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| /// MSI-X capability message control register state. Must be Clear if | ||
| /// a) capability is not supported or b) MSI-X table is not locked | ||
| pub msi_x_message_control: u16, |
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Out of curiosity, why is this only MSI-X as opposed to also the pre-X MSI?
This PR begins part of the process of merging the TDISP (Confidential VM Device Attestation + Encryption) prototype code into
mainand is part of a larger patch set split between other PRs to follow.This PR adds dependencies for TDISP implementation and traits used by both host code and OpenHCL.
openhcl/openhcl_tdisp: Addsopenhcl_tdispcrate which contains the implementation and traits for communicating with virtual devices that are TDISP capable.vm/devices/tdisp: Addstdispcrate which implements shared types and traits used across the guest to host boundary. This includes the serialization code for the custom guest-to-host protocol used to interface with the host VMM stack from the guest.Cargo.toml: Adds crates to root Cargo.tomlopenhcl/underhill_core: Addstdispandopenhcl_tdispto be built intounderhill_core, although none of these crates are used yet as of this PR.