Qemu to Avaota

[lupyuen]

No description provided.

[gemini-code-assist]

Hello @lupyuen, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

Summary of Changes

This pull request focuses on transitioning the emulation environment from QEMU to Avaota, specifically using the Unicorn emulator. The changes include setting up the build environment, mapping memory regions, and implementing hooks for code emulation. A key addition is a diagram illustrating the NuttX boot flow, providing a visual representation of the system's startup process. The PR also incorporates a unit test for the Arm64 MMU.

Highlights

• Build Environment Setup: The .vscode/tasks.json file is modified to include export RUST_BACKTRACE=1 in the build command, enabling Rust backtraces for debugging purposes.
• Memory Mapping and Code Emulation: The src/main.rs file is updated to map memory regions and implement hooks for code emulation using the Unicorn engine, replacing the previous QEMU setup.
• NuttX Boot Flow Diagram: A Mermaid diagram illustrating the NuttX boot flow is added to README.md, providing a visual representation of the system's startup process.
• Arm64 MMU Unit Test: The src/main.rs file includes a unit test for the Arm64 MMU, ensuring the memory management unit functions correctly within the emulated environment.

Changelog

Click here to see the changelog

• .vscode/bookmarks.json
  • Adds a bookmark for a specific line in unicorn_aarch64.c.
• .vscode/tasks.json
  • Adds export RUST_BACKTRACE=1 to the build command to enable Rust backtraces.
• README.md
  • Adds a Mermaid diagram illustrating the NuttX boot flow, with clickable links to source code.
  • Provides links to download the diagram in PDF, PNG, and SVG formats.
• mermaidRenderConfig.json
  • Sets maxTextSize to a large value to prevent text overflow in Mermaid diagrams.
• nuttx-boot-flow.mmd
  • Defines the Mermaid diagram code for the NuttX boot flow, including nodes, links, and click interactions.
• src/main.rs
  • Updates memory mapping to use the Unicorn engine instead of QEMU.
  • Implements code hooks for instruction emulation.
  • Adds a unit test for the Arm64 MMU.
  • Changes UART base address and initialization method.
  • Removes reliance on the nuttx/Image file and instead uses nuttx/nuttx.bin

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Did you know?

The Unicorn emulator is known for its fine-grained instrumentation, allowing developers to trace and analyze code execution at the instruction level.

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[gemini-code-assist]

Code Review

The pull request introduces changes to the build process, README, and adds a mermaid diagram and configuration. The addition of the mermaid diagram is a great way to visualize the boot flow. The change to the task.json file adds backtrace support, which is helpful for debugging. Overall, the changes seem beneficial, but let's take a closer look.

Summary of Findings

• Inconsistent UART base address: The UART base address is changed from 0x02500000 to 0x90000000. Verify that this change is correct and consistent with the hardware documentation.
• Memory mapping and kernel loading: The memory mapping and kernel loading process has been modified. Ensure that the new mapping and loading mechanism is correct and doesn't introduce any memory corruption or security vulnerabilities.
• Missing error handling: The code uses expect for error handling, which can cause the program to crash if an error occurs. Consider using more robust error handling mechanisms, such as Result and ?.

Merge Readiness

The pull request introduces significant changes to the system's core functionality. Due to the high severity issues identified, I recommend that these issues be addressed before merging. Additionally, other reviewers should examine the changes to ensure system stability. I am unable to approve this pull request, and other reviewers should approve this code before merging.

[gemini-code-assist]

The UART base address is changed from 0x02500000 to 0x90000000. Verify that this change is correct and consistent with the hardware documentation. Is this address correct for the QEMU emulated environment?

[gemini-code-assist]

The memory mapping and kernel loading process has been modified. Ensure that the new mapping and loading mechanism is correct and doesn't introduce any memory corruption or security vulnerabilities. Double check that the kernel_code.len() is the correct size to map, and that the ADDRESS is correct.

[gemini-code-assist]

The mermaid diagram is a great addition for visualizing the boot flow. Consider adding a brief explanation of the diagram and its purpose in the README.

[gemini-code-assist]

Consider using Result and ? for error handling instead of expect. This will allow the program to handle errors more gracefully without crashing. Also, consider logging the error message.

[gemini-code-assist]

The UART register offset is changed from 0x14 to 0x18. Is this correct for the QEMU emulated environment?