FlexServe: A Fast and Secure LLM Serving System for Mobile Devices with Flexible Resource Isolation

Fuente: arXiv
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Main Authors: Wu, Yinpeng, Chen, Yitong, Wang, Lixiang, Gu, Jinyu, Hua, Zhichao, Xia, Yubin
Format: Preprint
Published: 2026
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author Wu, Yinpeng
Chen, Yitong
Wang, Lixiang
Gu, Jinyu
Hua, Zhichao
Xia, Yubin
author_facet Wu, Yinpeng
Chen, Yitong
Wang, Lixiang
Gu, Jinyu
Hua, Zhichao
Xia, Yubin
contents Device-side Large Language Models (LLMs) have witnessed explosive growth, offering higher privacy and availability compared to cloud-side LLMs. During LLM inference, both model weights and user data are valuable, and attackers may even compromise the OS kernel to steal them. ARM TrustZone is the de facto hardware-based isolation technology on mobile devices, used to protect sensitive applications from a compromised OS. However, protecting LLM inference with TrustZone incurs significant overhead due to its inflexible isolation of memory and the NPU. To address these challenges, this paper introduces FlexServe, a fast and secure LLM serving system for mobile devices. It first introduces a Flexible Resource Isolation mechanism to construct Flexible Secure Memory (Flex-Mem) and Flexible Secure NPU (Flex-NPU). Both memory pages and the NPU can be efficiently switched between unprotected and protected modes. Based on these mechanisms, FlexServe designs a fast and secure LLM inference framework within TrustZone's secure world. The LLM-Aware Memory Management and Secure Inference Pipeline are introduced to accelerate inference. A Multi-Model Scheduler is proposed to optimize multi-model workflows. We implement a prototype of FlexServe and compare it with two TrustZone-based strawman designs. The results show that FlexServe achieves an average $10.05\times$ speedup in Time to First Token (TTFT) compared to the strawman, and an average $2.44\times$ TTFT speedup compared to an optimized strawman with pipeline and secure NPU enabled. For multi-model agent workflows, the end-to-end speedup is up to $24.30\times$ and $4.05\times$ compared to the strawman and optimized strawman, respectively.
format Preprint
id arxiv_https___arxiv_org_abs_2603_09046
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle FlexServe: A Fast and Secure LLM Serving System for Mobile Devices with Flexible Resource Isolation
Wu, Yinpeng
Chen, Yitong
Wang, Lixiang
Gu, Jinyu
Hua, Zhichao
Xia, Yubin
Cryptography and Security
Machine Learning
Operating Systems
Device-side Large Language Models (LLMs) have witnessed explosive growth, offering higher privacy and availability compared to cloud-side LLMs. During LLM inference, both model weights and user data are valuable, and attackers may even compromise the OS kernel to steal them. ARM TrustZone is the de facto hardware-based isolation technology on mobile devices, used to protect sensitive applications from a compromised OS. However, protecting LLM inference with TrustZone incurs significant overhead due to its inflexible isolation of memory and the NPU. To address these challenges, this paper introduces FlexServe, a fast and secure LLM serving system for mobile devices. It first introduces a Flexible Resource Isolation mechanism to construct Flexible Secure Memory (Flex-Mem) and Flexible Secure NPU (Flex-NPU). Both memory pages and the NPU can be efficiently switched between unprotected and protected modes. Based on these mechanisms, FlexServe designs a fast and secure LLM inference framework within TrustZone's secure world. The LLM-Aware Memory Management and Secure Inference Pipeline are introduced to accelerate inference. A Multi-Model Scheduler is proposed to optimize multi-model workflows. We implement a prototype of FlexServe and compare it with two TrustZone-based strawman designs. The results show that FlexServe achieves an average $10.05\times$ speedup in Time to First Token (TTFT) compared to the strawman, and an average $2.44\times$ TTFT speedup compared to an optimized strawman with pipeline and secure NPU enabled. For multi-model agent workflows, the end-to-end speedup is up to $24.30\times$ and $4.05\times$ compared to the strawman and optimized strawman, respectively.
title FlexServe: A Fast and Secure LLM Serving System for Mobile Devices with Flexible Resource Isolation
topic Cryptography and Security
Machine Learning
Operating Systems
url https://arxiv.org/abs/2603.09046