Modern cloud servers achieve significant performance improvements by exploiting data processing units (DPUs) to offload virtualization overhead.Unlike traditional monolithic hypervisors, this offloading approach splits VM state and distributes hypervisor functions across the DPU and the Host, transforming the cloud server from a single system into a sophisticated orchestration of multiple self-managed processing units.However, the failure rate of these systems has significantly increased, as errors from either the DPU or the Host can crash the entire machine.All these changes necessitate a comprehensive revamp of current VM fault tolerance and isolation mechanisms.This paper explores a novel approach to VM fault tolerance by treating the split hypervisors on the DPU SoC and the Host as redundant peers.We propose a fault-escaping scheme that enables VMs to escape from a failing SoC or Host.With hybrid synchronization, the entire VM state becomes fully accessible on either the SoC or the Host with minimum synchronization overhead (in kilobytes).Instead of recovering the failed hypervisor, this scheme migrates the verified VM state, allowing the VM to escape from the failure

Transport Layer Security (TLS) connections involve costly cryptographic operations which incur significant resource consumption in the cloud. Hardware accelerators are affordable substitutes of expensive CPU cores to accommodate with the constantly increasing security requirements of datacenters. Existing accelerators virtualization mainly relies on passthrough of Single Root I/O Virtualization (SR-IOV) devices. However, deficiency of service accessibility, functionality and availability make device passthrough not an optimal solution for heterogeneous accelerators with different capabilities. To make up the gap, we propose vCrypto, a unified para-virtualization framework for heterogeneous cryptographic resources. vCrypto supports stateful crypto requests offloading and result retrieval with session lifecycle management and event driven notification. vCrypto transparently integrates virtual crypto device capabilities into the OpenSSL framework to benefit existing applications that are based on crypto library APIs without modification. Multiple physical resources can be partitioned flexibly and scheduled cooperatively to enhance the functionality, performance and robustness of virtual crypto service. Finally, vCrypto achieves an optimized performance with two layers polling and memory sharing mechanism. The comprehensive experiments show that with the same cryptographic resources used, vCrypto framework can provide 2.59x to 3.36x higher AES-CBC-HMAC-SHA1 throughput compared to passthrough SR-IOV device.

To achieve efficient resource management on a graphics processing unit (GPU), there is a demand to develop a framework for scheduling virtualized resources in cloud gaming. In this article, we propose VGRIS, a resource management framework for virtualized GPU resource isolation and scheduling in cloud gaming. A set of application programming interfaces (APIs) is provided so that a variety of scheduling algorithms can be implemented within the framework without modifying the framework itself. Three scheduling algorithms are implemented by the APIs within VGRIS. Experimental results show that VGRIS can effectively schedule GPU resources among various workloads.

As the virtualization technology for GPUs matures, cloud gaming has become an emerging application among cloud services. In addition to the poor default mechanisms of GPU resource sharing, the performance of cloud games is inevitably undermined by various runtime uncertainties such as rendering complex game scenarios. The question of how to handle the runtime uncertainties for GPU resource sharing remains unanswered. To address this challenge, we propose vGASA, a virtualized GPU resource adaptive scheduling algorithm in cloud gaming. vGASA interposes scheduling algorithms in the graphics API of the operating system, and hence the host graphic driver or the guest operating system remains unmodified. To fulfill the service level agreement as well as maximize GPU usage, we propose three adaptive scheduling algorithms featuring feedback control that mitigates the impact of the runtime uncertainties on the system performance. The experimental results demonstrate that vGASA is able to maintain frames per second of various workloads at the desired level with the performance overhead limited to 5-12 percent.