Zixuan Wang
Software Engineer, PhD
About
I am Zixuan Wang (王子轩), a software engineer at Apple working on CloudOS. I received my PhD from the University of California San Diego, where I worked with Prof. Jishen Zhao on architecture and systems research. I also worked with Prof. Steven Swanson at NVSL Lab, UCSD.
My research focuses on building scalable and secure systems with emerging architecture, systems, and programming technologies. At each level, I conduct systematic analysis, from characterizing performance to attacking and securing the system to developing programming support.
My industrial work across multiple companies has focused on deploying emerging technologies in real-world systems, especially trusted execution using confidential virtual machines. At Google in 2021, I worked on modernizing the Linux KVM testing framework with UEFI and AMD SEV/SEV-ES support, which became the first such contribution merged into the Linux KVM community. At Meta in 2022, I worked on the initial confidential virtual machine platform by initiating and developing the system and software support, and the work was highlighted at Meta's Annual Security Summit. At Google in 2023, I enhanced guest confidential computing with measurable hypervisor service code by leveraging AMD SEV-SNP SVSM. Previously at SK hynix in 2019, I worked on early evaluation of CXL prototypes, which led to one of the first publications on CXL systems.
My open-source work facilitates research, industry, and personal usage. I have contributed dozens of patches to the Linux KVM community, which are now used by cloud companies and open-source communities. I also maintain multiple open-source projects on GitHub that have impacted more than 200,000 users across research, tooling, and developer workflows.
I earned my bachelor's degree from Zhejiang University, where I worked with Prof. Wenzhi Chen and Prof. Qingsong Shi on computer architecture and operating systems at the Computer Architecture Lab.
Fun Facts
- I take photos in my photo gallery.
- My radio call sign is KN6TTT.
- Here is Inu, my kitten, and his Instagram.
- I have a Guinness Record.
- I play table tennis and badminton.
- I learned snow skiing back in my hometown.
- I learned surfing at UC San Diego.
- I play games on PC, Switch, PS4, and PS5.
- I have a 3D printer.
- I have a rack in my closet.
- I play guitar.
- I am a fan of Sony products.
- I have a compound bow and am practicing for bow hunting.
- I ride a Kawasaki Ninja 400 motorcycle.
Experience
Senior Software Engineer
Apple
2025 Apr - Present
I am working on private cloud computing and CloudOS at Apple.
Software Engineer
Apple
2024 Sept - 2025 Apr
I worked on private cloud computing and CloudOS at Apple.
Graduate Research Assistant
University of California, San Diego
2018 Sept - 2024 Aug
I worked in STABLE Lab and NVSL Lab on architecture and systems design for memory and secure systems.
- Hiemdall: a heterogeneous system benchmarking framework demonstrated on multiple CXL-based systems.
- NVLeak: an off-chip memory architecture reverse engineering and covert/side-channel attack framework.
- COARSE: a disaggregated memory system for distributed deep learning training.
- Ayudante: a learning-based persistent memory automatic programming framework.
- LENS: a profiler that discovers NVRAM DIMM microarchitecture design.
- VANS: a cycle-level NVRAM simulator validated against real products.
Software Engineering Intern
2023 June - 2023 Sept
Built AMD SEV-SNP SVSM support in Google Cloud to enhance confidential computing. I received a peer bonus for this work.
Student Researcher
Meta
2022 Sept - 2023 Jan
Deployed the first confidential virtual machine platform at Meta.
Software Engineering Intern
Meta
2022 June - 2022 Sept
Initiated and developed confidential virtual machine platform support at Meta.
Software Engineering Intern
2021 June - 2021 Sept
Developed UEFI and AMD SEV/SEV-ES support for KVM-unit-tests. The code was merged by the Linux KVM community, and I received two peer bonuses during this internship.
Research Intern
SOLAB, SK hynix America
2019 June - 2019 Sept
Evaluated the performance of CXL memory prototypes and enabled GPU direct access to coherent off-chip memory.
Undergraduate Research Assistant
Zhejiang University
2015 - 2018
I worked in the Computer Architecture Lab on operating systems and computer architecture.
- Developed the ZJUNIX operating system from scratch and ran it on a self-designed MIPS SoC on FPGA.
- Built an FPGA accelerator for high-frequency trading.
- Worked on the portable modular 3D bioprinter project, which earned the Outstanding Prize in Challenge Cup.
Publications
In Progress
The Hitchhiker's Guide to Programming and Optimizing CXL-Based Heterogeneous Systems
ArXiv'24
CXLeak: Architectural Attacks via Practical CXL Systems
Work in Progress
Conference & Journal
HybridTier: an Adaptive and Lightweight CXL-Memory Tiering System
ASPLOS'26
COLA: Characterizing and Optimizing the Tail Latency for Safe Level-4 Autonomous Vehicle Systems
ICRA'25
NVLeak: Off-Chip Side-Channel Attacks via Non-Volatile Memory Systems
USENIX Security'23
Enabling Efficient Large-Scale Deep Learning Training with Cache Coherent Disaggregated Memory Systems
HPCA'22
Ayudante: A Deep Reinforcement Learning Approach to Assist Persistent Memory Programming
ATC'21
Characterizing and Modeling Non-Volatile Memory Systems
IEEE Micro TopPicks'21
Characterizing and Modeling Non-Volatile Memory Systems
MICRO'20
Preprint & Workshop
Towards LLM-Powered Verilog RTL Assistant: Self-Verification and Self-Correction
ArXiv'24
Fork is All You Need in Heterogeneous Systems
ASPLOS HCDS Workshop'24
Characterizing WebAssembly Performance in the Era of Serverless Computing
ISSTA'23 SRC
Enabling Fast Recovery for Autonomous Vehicle Systems with Linux Container Checkpointing
SOSP'21 SRC
Basic Performance Measurements of the Intel Optane DC Persistent Memory Module
ArXiv'19
Reliable and Flexible Large Scale Memory Network
NVMW'19
Other
A Modulized Portable 3D Bioprinter
China Patent
Service
Committee
University of California, San Diego
- Submission Chair @ MICRO 2020
- Shadow TPC @ EuroSys 2023
Organizing Committee
Students@Systems
2022 Jan - Present
I am one of the founders and organizers of Students@Systems, a community for PhD students in systems research that runs talks, podcasts, and panels for the broader systems community.
I have helped organize more than ten online events, including panels on applying for PhD programs and interviews with researchers from underrepresented groups.
Submission Chair
MICRO 2021
2021 Mar - 2023 July
I served as submission co-chair for MICRO 2021, working with program chairs to manage submissions and organize the TPC meeting.
I also open-sourced MightyPC, a toolkit I built to manage conference submissions. It has since been used by MICRO'21, IEEE MICRO TopPicks'22, HPCA'22, MICRO'22, DSN'23, and others.
Invited Talks
NVLeak: Off-Chip Side-Channel Attacks via Non-Volatile Memory Systems
- NVMW'23
Enabling Efficient Large-Scale Deep Learning Training with Cache Coherent Disaggregated Memory Systems
- Intel
- IBM Research
- SK hynix
- Micron
- Alibaba Cloud USA
- Foundational Microarchitecture Research (FoMR)
- CRISP Center at Semiconductor Research Corporation
Characterizing and Modeling Non-Volatile Memory Systems
- TECHCON'20
- NVMW'21
- FoMR
- CRISP Center at SRC
Trust but Verify: Co-Locating Hypervisor Services with User Code via AMD SEV-SNP SVSM
- Google Cloud'23
Securing User Data with Confidential Virtual Machine
- Meta Annual Security Summit'22
Modernizing KVM-Unit-Tests with UEFI and AMD Confidential Virtual Machine
- Google Cloud'21
- AMD'21
Teaching
Teaching Assistant: Introduction to Computer Architecture
UC San Diego, 2021
Undergraduate-level computer architecture course.
Associate Instructor: Hardware-Based Computer System Design
Zhejiang University, 2018
Developed and instructed a course that guides students to build their own CPU on FPGA and run their own operating system.
Associate Instructor: Operating System Course
Zhejiang University, 2017
Developed and instructed a course that guides students to build an operating system from scratch.
Projects
Architectural Security Attacks in Main Memory Systems
June 2023
Side-channel attacks in non-volatile main memory systems.
- C
- x86 Assembly
- Linux Kernel
- Reverse Engineering
- Side-Channel Attacks
- Software-based reverse engineering of the microarchitecture of non-volatile main memory.
- Side-channel attacks that leak sensitive data such as database tables and private encryption keys.
Trusted Execution of Hypervisor Code within Guest Virtual Machine
June 2023
Initiated AMD SEV-SNP SVSM support to enhance Google Cloud confidential virtual machines.
- C
- x86 Assembly
- KVM
- UEFI
- AMD SEV-SNP
- AMD SVSM
- Rust
Built the initial SVSM support in Google Cloud's Linux kernel, hypervisor, guest firmware, and guest kernel.
Confidential Virtual Machine Platform
June 2022
Initiated and developed the first confidential VM platform at Meta, later highlighted at Meta's Annual Security Summit.
- QEMU
- C++
- x86 Assembly
- KVM
- UEFI
- AMD SEV
- Rust
Built the initial software and operating system support for the first confidential virtual machine platform at Meta.
KVM-unit-tests under UEFI and AMD SEV/SEV-ES
Sep. 2021
Started as my 2021 Google internship project and later continued in spare time.
- C
- x86 Assembly
- KVM
- SeaBIOS
- UEFI
- AMD SEV
- AMD SEV-ES
- GNU Toolchain
- Linker Script
- Implemented UEFI support as an alternative to the existing SeaBIOS plus Multiboot flow.
- Implemented AMD SEV and SEV-ES support for a widely adopted KVM testing framework.
Accelerating Distributed Training of LLM
Oct. 2021
Built a CXL-based disaggregated memory system for large-model training infrastructure. Accepted by HPCA 2022.
- CXL
- FPGA
- TensorFlow
- CUDA
- Verilog
- Built a disaggregated memory prototype in FPGA.
- Enabled multi-GPU training with effectively expanded memory using CXL-based off-chip memory.
LENS: A Low-Level NVRAM Profiler
Sep. 2020
MICRO 2020 paper: Characterizing and Modeling Non-Volatile Memory Systems.
- C
- Linux Kernel
- x86 Assembly
- Built the first profiler that can discover non-volatile memory on-DIMM microarchitecture.
- Runs in Linux kernel space with microbenchmarks written in x86 assembly.
- Source code
VANS: A Validated NVRAM Simulator
Sep. 2020
MICRO 2020 paper: Characterizing and Modeling Non-Volatile Memory Systems.
- C++17
- Python
- R
- Cycle-Accurate Simulation
- Built a cycle-level NVRAM simulator validated against Intel Optane persistent memory.
- Used modern C++ to simplify the implementation and improve simulator throughput.
- Source code
GPU Direct Access to Cache-Coherent Off-Chip Memory
Sep. 2019
Work completed during my SK hynix internship.
- FPGA
- GPU
- Linux
- GEN-Z
- CXL
- Evaluated the GEN-Z memory prototype and developed a framework for GPU direct access through PCIe.
- Showed up to 16x faster cuDF performance compared with indirect CPU-mediated access.
FPGA Accelerated High-Frequency Trading
Sep. 2018
Deployed in a production environment.
- FPGA
- Linux
- Userspace IO
- MIPS Assembly
- Offloaded decision procedures to FPGA and forwarded network data directly to the accelerator.
- Used 10 Gigabit Ethernet for communication between FPGA and host PC.
QEMU micro:bit Emulator
May. 2018
A micro:bit emulator based on QEMU.
- C
- ARM Assembly
- ARM Mbed OS
- Bootloader
- QEMU
- Implemented Cortex-M0 features on top of QEMU's Cortex-M3 emulator.
- Added peripheral emulators including LED matrix, timer, clock generator, and random number generator.
- Reverse engineered the micro:bit bootloader and validated the hardware emulation with Mbed OS.
- Source code
ZJUNIX Operating System
Apr. 2017
An operating system built from scratch and running on a self-designed SoC.
- Open Source
- OS Design
- Bootloader
- C
- MIPS Assembly
- Linker Script
- Implemented bootloader, interrupts and exceptions, and kernel memory management.
- Built process scheduling, shell and core userland utilities, FAT and ext2 filesystem support.
ZJU-SoC
Dec. 2016
An SoC built from scratch using FPGA.
- Open Source
- FPGA
- Verilog
- CPU Design
- Peripheral Design
- Implemented a 5-stage pipeline MIPS32 CPU with 93 instructions and two levels of cache.
- Integrated DDR3, VGA, PS/2, and SD controller peripherals.
- Capable of running both ZJUNIX and Arduino programs.
Portable 3D Bioprinter
Dec. 2016
A portable modular 3D bioprinter that prints tissue directly on wounds.
- Image Processing
- Mechanical Design
- Real-Time Systems
- Demo video
- Used FPGA-accelerated edge detection to meet real-time requirements.
- Resulted in utility model patent 201720246090.1 and multiple awards.
FPGA Accelerated Fluid Simulation
Aug. 2016
An FPGA acceleration of PCISPH fluid simulation.
- Graphics Engine
- FPGA
- Used FPGA for simulation and PC for rendering.
- FPGA communicated with PC through Ethernet.
- Won second prize in Digilent Design Contest China 2017.
Projects for Fun
VS Code LinkerScript
Aug. 2018
The first GNU linker script highlighting extension for VS Code, based on TextMate grammars.
- VS Code Extension
- YAML
- Linker Script
- VS Code Marketplace
- GitHub Repo
- 180K+ installs
ZJU Thesis
May. 2018
LaTeX template for Zhejiang University graduate design and thesis.
Makefile Templates
July 2017
Makefile templates for C and C++ projects.
- Makefile
Chinese Input Method in MIPS
July 2016
A Chinese input method written in pure MIPS assembly.
- MIPS Assembly
- Keyboard Interrupt
- VGA Display
- Implemented pinyin input and GB2312 lookup in roughly 2,000 lines of MIPS assembly.
- Demo picture
Tiger Language Compiler
May 2017
A simple compiler for the Tiger programming language.
- Bison
- Flex
- C++11/14
- Implemented lexical analysis, parsing, abstract syntax tree generation, and intermediate code generation.