NVX phase 1: minimal signed MicroVM integration by huzaifa-d · Pull Request #1528 · microsoft/mxc

Huzaifa Danish (huzaifa-d) · 2026-10-19T17:58:52Z

📖 Description

Phase 1 of the NVX integration stack.
Replace the active Nanvix integration with the minimum Windows x64 NVX captured create-and-run path, behind the existing microvm feature.

Phase 1 Image limitation: The workload image is fixed to mcr.microsoft.com/azurelinux/base/core:3.0. Requests cannot select another image. This is temporary and handled in phase two.

🔗 References

NVX release: https://github.com/microsoft/nvx/releases/tag/v0.1.0-dev.0430ce79d125
SDK integration notes: src/mxc-sdk/README.md#experimental-nvx-create-and-run
Related integration design: feat: NVX integration design doc #1448

✅ Checklist

Signed the Contributor License Agreement
Linked to an issue
Updated documentation (if applicable)
Updated Copilot instructions (if build, architecture, or conventions changed)
If this PR changes Cargo.lock, the dependency-feed-check check passes (see pull request builds)

📋 Issue Type

Bug fix
Feature
Task

GitHub Actions runs the PR validation build automatically. The ADO pipeline
(MXC-PR-Build) is the Azure version of the PR pipeline, kept in parity with the GitHub
Actions build; it runs on merge to main, and Microsoft reviewers with write access can trigger it
on a PR with /azp run. See pull request builds.

If the dependency-feed-check check fails on a new dependency, the crate must be added to
the feed before the PR can pass. See pull request builds
for the steps.

Microsoft Reviewers: Open in CodeFlow

Add the minimal signed create-and-run NVX0430 bundle. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: aee99423-dfee-4d61-86e9-421b944c4cc0

azure-pipelines · 2026-10-19T17:59:02Z

Azure Pipelines: There may be pipelines that require an authorized user to comment /azp run to run.

Copilot

🟡 Changes recommended

Output preservation and test-validation defects remain unresolved.

3 open issues

Propagate the first test command's failure · New
Preserve raw bytes through the executor relay · New
Match the executor's actual timeout diagnostic · New

What changed in this PR

Introduces phase 1 of NVX integration, replacing active Nanvix execution with experimental Windows x64 captured create-and-run support.

Changes:

Adds NVX execution, policy validation, and engine routing.
Pins, verifies, and stages the signed runtime bundle.
Updates tests, build scripts, and documentation; disables Linux MicroVM execution.

File	Description
tests/scripts/run_microvm_tests.ps1	Adapts tests to the signed NVX bundle.
tests/scripts/README.md	Documents active and legacy test helpers.
tests/configs/microvm_timeout.json	Uses a shell timeout workload.
tests/configs/microvm_stdlib.json	Checks guest shell and OS.
tests/configs/microvm_multiline.json	Uses shell Fibonacci logic.
tests/configs/microvm_large_output.json	Generates output through the shell.
tests/configs/microvm_hello.json	Adds shell greeting.
tests/configs/microvm_exit_code.json	Tests shell exit propagation.
tests/configs/microvm_error.json	Tests shell stderr and failure.
src/testing/fuzz/fuzz_targets/validator.rs	Routes supported fuzz validation to NVX.
src/mxc-sdk/tests/wxc_e2e_tests_e2e_windows.rs	Gates and adapts MicroVM tests.
src/mxc-sdk/tests/wxc_e2e_tests_e2e_linux_microvm.rs	Disables historical Linux coverage.
src/mxc-sdk/tests/nvx_e2e.rs	Adds rejection and runtime integration tests.
src/mxc-sdk/tests/nvx_bundle_integrity.rs	Tests bundle integrity enforcement.
src/mxc-sdk/src/lib.rs	Supports captured JSON execution results.
src/mxc-sdk/src/core/mxc_engine/run.rs	Replaces Nanvix runner dispatch.
src/mxc-sdk/src/core/mxc_engine/mod.rs	Adds captured execution orchestration.
src/mxc-sdk/src/core/mxc_common/models.rs	Tracks explicit policy-field presence.
src/mxc-sdk/src/core/mxc_common/config_parser.rs	Preserves presence and tests backend rejection.
src/mxc-sdk/src/core/mxc_common/cmdline.rs	Selects POSIX quoting for MicroVM.
src/mxc-sdk/src/backends/nvx/runtime.rs	Configures the bundled agent and workload image.
src/mxc-sdk/src/backends/nvx/runner.rs	Implements execution and cleanup.
src/mxc-sdk/src/backends/nvx/policy.rs	Rejects unsupported phase-1 policy.
src/mxc-sdk/src/backends/nvx/mod.rs	Declares NVX modules.
src/mxc-sdk/src/backends/mod.rs	Gates NVX to Windows x64.
src/mxc-sdk/README.md	Documents experimental execution support.
src/mxc-sdk/Cargo.toml	Adds pinned dependency and disables publishing.
src/mxc-sdk/build/build_nvx_bundled.rs	Verifies and stages bundle contents.
src/mxc-sdk/build.rs	Invokes NVX staging.
src/Cargo.lock	Records NVX dependencies.
README.md	Updates platform support and scope.
docs/schema.md	Documents NVX request restrictions.
docs/development/build-and-test/ci-validation-infrastructure.md	Clarifies phase-1 validation boundaries.
docs/backends/nanvix/nanvix.md	Replaces legacy guidance with NVX documentation.
build.sh	Rejects Linux MicroVM builds.
build.bat	Copies the signed Windows bundle.
.github/workflows/microvm-e2e.yml	Builds and tests NVX integration.
.cargo/config.toml	Pins bundle download and verification settings.

_{Review effort: Balanced}

Preserve executor output bytes and propagate test failures. Correct timeout assertions and simplify review wording and documentation. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Link the root README to the SDK integration notes and document host prerequisites and policy restrictions there. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Restore the Nanvix guide unchanged from the PR base and keep the README and CI notes focused on the current integration. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Copilot

🔵 Needs a closer look

Unbounded output capture risks host memory exhaustion, and incomplete preflight validation lets invalid requests reach VM startup.

No open issues 🎉

2 previously missed issues

In code that hasn't changed since last review

Validator misses NVX execution request constraints

src/mxc-sdk/src/backends/nvx/policy.rs:78

This validator accepts whitespace-only commands, guest working directories longer than 4095 bytes, and more than 256 short environment entries, although the pinned NVX API rejects them. --dry-run therefore reports success, and actual execution can pull the image and boot a VM before client.exec rejects the request. Reject these deterministic cases here and cover them in the host-only request matrix. Calling client.validate_exec before provisioning can additionally guard the execution path, but does not replace validation used by dry-run.

Unbounded command output can exhaust executor memory

src/mxc-sdk/src/backends/nvx/runner.rs:90

The pinned NVX agent has no total output limit, and wait_with_output() collects both streams with read_to_end into growing vectors. An allowed command such as while :; do printf 'xxxxxxxxxxxxxxxx\n'; done with timeout disabled can exhaust the executor or embedding application's memory and abort it before stop/deprovision runs. Read both streams concurrently with a bounded capture budget, cancel execution on overflow, and still perform cleanup.

3 resolved since last review

_{Review effort: Balanced}

NVX0430 phase 1: add minimal signed create-run bundle

287f763

Add the minimal signed create-and-run NVX0430 bundle. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: aee99423-dfee-4d61-86e9-421b944c4cc0

Copilot AI balanced review requested due to automatic review settings October 19, 2026 17:58

Copilot started reviewing on behalf of Huzaifa Danish (huzaifa-d) October 19, 2026 17:59

View session

Copilot AI reviewed Oct 19, 2026

View reviewed changes

Comment thread .github/workflows/microvm-e2e.yml Outdated

Comment thread src/mxc-sdk/src/backends/nvx/runner.rs Outdated

Comment thread src/mxc-sdk/tests/nvx_e2e.rs Outdated

Address NVX phase 1 review feedback

a5ba733

Preserve executor output bytes and propagate test failures. Correct timeout assertions and simplify review wording and documentation. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Huzaifa Danish (huzaifa-d) mentioned this pull request Oct 19, 2026

NVX phase 1: signed MicroVM integration and review fixes huzaifa-d/mxc#3

Draft

2 of 8 tasks

huzaifa-msft and others added 2 commits October 19, 2026 12:52

Fix NVX documentation links after removing backend guide

6b0fcca

Link the root README to the SDK integration notes and document host prerequisites and policy restrictions there. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Preserve Nanvix guide and simplify NVX documentation

27c0abf

Restore the Nanvix guide unchanged from the PR base and keep the README and CI notes focused on the current integration. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Copilot AI balanced review requested due to automatic review settings October 19, 2026 21:59

Copilot started reviewing on behalf of Huzaifa Danish (huzaifa-d) October 19, 2026 22:00

View session

Copilot AI reviewed Oct 19, 2026

View reviewed changes

Huzaifa Danish (huzaifa-d) marked this pull request as ready for review October 20, 2026 18:07

Huzaifa Danish (huzaifa-d) requested a review from a team as a code owner October 20, 2026 18:07

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NVX phase 1: minimal signed MicroVM integration - #1528

NVX phase 1: minimal signed MicroVM integration#1528
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Huzaifa Danish (huzaifa-d) commented Oct 19, 2026 •

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📖 Description

🔗 References

✅ Checklist

📋 Issue Type

Microsoft Reviewers: Open in CodeFlow

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🟡 Changes recommended

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Huzaifa Danish (huzaifa-d) commented Oct 19, 2026 •

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