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  1. Due to the increasing complexity of modern hetero-geneous System-on-Chips (SoC) and the growing vulnerabilities, security risk assessment and quantification is required to measure the trustworthiness of a SoC. This paper describes a systematic approach to model the security risk of a system for malicious hardware attacks. The proposed method uses graph analysis to assess the impact of an attack and the Common Vulnerability Scoring System (CVSS) is used to quantify the security level of the system. To demonstrate the applicability of the proposed metric, we consider two open source SoC benchmarks with different architectures. The overall risk is calculated using the proposed metric by computing the exploitability and impact of attack on critical components of a SoC.
    Free, publicly-accessible full text available August 1, 2023
  2. Cloud deployments now increasingly exploit Field-Programmable Gate Array (FPGA) accelerators as part of virtual instances. While cloud FPGAs are still essentially single-tenant, the growing demand for efficient hardware acceleration paves the way to FPGA multi-tenancy. It then becomes necessary to explore architectures, design flows, and resource management features that aim at exposing multi-tenant FPGAs to the cloud users. In this article, we discuss a hardware/software architecture that supports provisioning space-shared FPGAs in Kernel-based Virtual Machine (KVM) clouds. The proposed hardware/software architecture introduces an FPGA organization that improves hardware consolidation and support hardware elasticity with minimal data movement overhead. It also relies on VirtIO to decrease communication latency between hardware and software domains. Prototyping the proposed architecture with a Virtex UltraScale+ FPGA demonstrated near specification maximum frequency for on-chip data movement and high throughput in virtual instance access to hardware accelerators. We demonstrate similar performance compared to single-tenant deployment while increasing FPGA utilization, which is one of the goals of virtualization. Overall, our FPGA design achieved about 2× higher maximum frequency than the state of the art and a bandwidth reaching up to 28 Gbps on 32-bit data width.
    Free, publicly-accessible full text available June 30, 2023
  3. In this article, we survey existing academic and commercial efforts to provide Field-Programmable Gate Array (FPGA) acceleration in datacenters and the cloud. The goal is a critical review of existing systems and a discussion of their evolution from single workstations with PCI-attached FPGAs in the early days of reconfigurable computing to the integration of FPGA farms in large-scale computing infrastructures. From the lessons learned, we discuss the future of FPGAs in datacenters and the cloud and assess the challenges likely to be encountered along the way. The article explores current architectures and discusses scalability and abstractions supported by operating systems, middleware, and virtualization. Hardware and software security becomes critical when infrastructure is shared among tenants with disparate backgrounds. We review the vulnerabilities of current systems and possible attack scenarios and discuss mitigation strategies, some of which impact FPGA architecture and technology. The viability of these architectures for popular applications is reviewed, with a particular focus on deep learning and scientific computing. This work draws from workshop discussions, panel sessions including the participation of experts in the reconfigurable computing field, and private discussions among these experts. These interactions have harmonized the terminology, taxonomy, and the important topics covered in this manuscript.
    Free, publicly-accessible full text available September 30, 2023
  4. Convolutional Neural Networks are compute-intensive learning models that have demonstrated ability and effectiveness in solving complex learning problems. However, developing a high-performance FPGA accelerator for CNN often demands high programming skills, hardware verification, precise distribution localization, and long development cycles. Besides, CNN depth increases by reuse and replication of multiple layers. This paper proposes a programming flow for CNN on FPGA to generate high-performance accelerators by assembling CNN pre-implemented components as a puzzle based on the graph topology. Using pre-implemented components allows us to use the minimum of resources necessary, predict the performance, and gain in productivity since there is no need to synthesize any HDL code. Furthermore, components can be reused for a different range of applications. Through prototyping, we demonstrated the viability and relevance of our approach. Experiments show a productivity improvement of up to 69% compared to a traditional FPGA implementation while achieving over 1.75× higher Fmax with lower resources and power consumption.
  5. As the complexity of FPGA architectures increases, there is a raising need to improved productivity and performance in several computing domains such as image processing, financial analytics, edge computing and deep learning. However, vendor tools are mostly general-purpose as they attempt to provide an acceptable quality of result (QoR) on a broad set of applications, which may not exploit application/domain-specific characteristics to deliver higher QoR. In this paper, we present a divide-and-conquer design flow that enables application/domain-specific optimization on the design of convolutional neural network (CNN) architectures on Xilinx FPGAs. The proposed approach follows three fundamental steps; Step 1: Break the design down into components, Step 2: Implement these separate components, and Step 3: Efficiently generate the final design by assembling pre-built components with minimal QoR lost. Recent research has even demonstrated that such approaches may provide better QoR than that of the traditional Vivado flow in some instances [1], [2]. By pre-implementing specific components of a design, higher performance can be achieved locally and maintained to a certain extent when assembling the final circuit. This approach is supported by two main observations [1]: (1) vendor tools such as Vivado tend to deliver high performance results on small modules inmore »a design. (2) Computing applications such as machine learning designs increase in size by replicating modules. CNN inference refers to the forward propagation of M input images through L layers. The repetition of components within CNN architectures make them suitable candidates for RapidWright implementation as the CNN sub-modules can be optimized for performance in standalone, and the achieved performance can be preserved when replicating and relocating the modules across the FPGA.« less
  6. FPGAs are getting an increasing interest from public clouds and cloud research projects. They are particularly attractive because of their ability to serve as energy efficient and customizable hardware accelerators. Commercial clouds have however highlighted the lack of multi-tenancy support, which does not permit hardware consolidation as it is not possible to space-share FPGA resources between multiple tenants. In this paper, we propose an architecture that divides the FPGA into logically isolated regions that we call ” virtual regions ” (VR). The VRs are immersed in a NoC interconnect allowing flexible communication, fast data movement, and low hardware footprint. The proposed architecture enables multitenancy as VRs can be allocated to different tenants at runtime.
  7. Cloud deployments now increasingly provision FPGA accelerators as part of virtual instances. While FPGAs are still essentially single-tenant, the growing demand for hardware acceleration will inevitably lead to the need for methods and architectures supporting FPGA multi-tenancy. In this paper, we propose an architecture supporting space-sharing of FPGA devices among multiple tenants in the cloud. The proposed architecture implements a network-on-chip (NoC) designed for fast data movement and low hardware footprint. Prototyping the proposed architecture on a Xilinx Virtex Ultrascale + demonstrated near specification maximum frequency for on-chip data movement and high throughput in virtual instance access to hardware accelerators. We demonstrate similar performance compared to single-tenant deployment while increasing FPGA utilization (we achieved 6× higher FPGA utilization with our case study), which is one of the major goals of virtualization. Overall, our NoC interconnect achieved about 2× higher maximum frequency than the state-of-the-art and a bandwidth of 25.6 Gbps