201 research outputs found
A TrustZone-assisted hypervisor supporting dynamic partial reconfiguration
Dissertação de mestrado em Engenharia Eletrónica Industrial e ComputadoresTraditionally, embedded systems were dedicated single-purpose systems characterised
by hardware resource constraints and real-time requirements. However,
with the growing computing abilities and resources on general purpose platforms,
systems that were formerly divided to provide different functions are now merging
into one System on Chip. One of the solutions that allows the coexistence
of heterogeneous environments on the same hardware platform is virtualization
technology, usually in the form of an hypervisor that manage different instances
of OSes and arbitrate their execution and resource usage, according to the chosen
policy.
ARM TrustZone has been one of the technologies used to implement a virtualization
solution with low overhead and low footprint. µRTZVisor a TrustZoneassisted
hypervisor with a microkernel-like architecture - is a bare-metal embedded
hypervisor that relies on TrustZone hardware to provide the foundation to implement
strong spatial and temporal isolation between multiple guest OSes.
The use of Partial Reconfiguration allows the designer to define partial reconfigurable
regions in the FPGA and reconfigure them during runtime. This allows
the system to have its functionalities changed during runtime using Dynamic Partial
Reconfiguration (DPR), without needing to reconfigure all the FPGA. This
is a major advantage, as it decreases the configuration overhead since partial bitstreams
are smaller than full bitstreams and the reconfiguration time is shorter.
Another advantage is reducing the need for larger logic areas and consequently
reducing their power consumption.
Therefore, a hypervisor that supports DPR brings benefits to the system. Aside
from better FPGA resources usage, another improvement that it brings, is when
critical hardware modules misbehave and the hardware module can be replaced.
It also enables the controlling and changing of hardware accelerators dynamically,
which can be used to meet the guest OSes requests for hardware resources as the
need appears. The propose of this thesis is extending the µRTZVisor to have a
DPR mechanism.Tradicionalmente, os sistemas embebidos eram sistemas dedicados a uma única
tarefa e apenas limitados pelos seus requisitos de tempo real e de hardware. Contudo,
como as plataformas de uso geral têm cada vez mais recursos e capacidade
de processamento, muitos dos sistemas que executavam separadamente, passaram
a apenas um sistema em plataforma recorrendo à tecnologia de virtualização, normalmente
como um hipervisor que é capaz de gerir múltiplos sistemas operativos
arbitrando a sua execução e acesso aos recursos da plataforma de acordo com uma
politica predefinida.
A tecnologia TrustZone da ARM tem sido uma das soluções implementadas
sem ter grande impacto na performance dos sistemas operativos. µRTZVisor é um
dos hipervisores baseados na TrustZone para implementar um isolamento espacial
e temporal entre múltiplos sistemas operativos, sendo que defere de outras uma
vez que é de arquitectura microkernel.
O uso de Reconfiguração Parcial Dinâmica (RPD) permite ao designer definir
várias regiões reconfiguráveis no FPGA que podem ser dinamicamente reconfiguradas
durante o período de execução. Esta é uma grande vantagem, porque reduz
os tempos de reconfiguração de módulos reconfiguráveis uma vez que os seus bitstreams
são mais pequenos que bitstreams para a plataforma toda. A tecnologia
também permite que nos FPGAs não sejam necessárias áreas lógicas tão grandes,
o que também reduz o consumo de energia da plataforma.
Um hipervisor que suporte RPD traz grandes benefícios para o sistema, nomeadamente
melhor uso dos recursos de FPGA, implementação de aceleradores em
hardware dinamicamente reconfiguráveis, e tratamento de falhas no hardware. Se
houverem módulos que estejam a demonstrar comportamentos inesperados estes
podem ser reconfigurados. O uso de aceleradores reconfiguráveis permite que o
hardware seja adaptável conforme a necessidade destes pelos diferentes sistemas
operativos. A proposta desta dissertação é então estender o µRTZVisor para ter
a capacidade de usar módulos reconfiguráveis por RPD
Hardware IPC for a TrustZone-assisted Hypervisor
Dissertação de mestrado em Engenharia Eletrónica Industrial e ComputadoresIn this modern era ruled by technology and the IoT (Internet of Things),
embedded systems have an ubiquitous presence in our daily lives. Although they
do differ from each other in their functionalities and end-purpose, they all share the
same basic requirements: safety and security. Whether in a non-critical system
such as a smartphone, or a critical one, like an electronic control unit of any
modern vehicle, these requirements must always be fulfilled in order to accomplish
a reliable and trust-worthy system.
One well-established technology to address this problem is virtualization. It
provides isolation by encapsulating each subsystem in separate Virtual-Machines
(VMs), while also enabling the sharing of hardware resources. However, these
isolated subsystems may still need to communicate with each other. Inter-Process
Communication is present in most OSes’ stacks, representing a crucial part of
it, which allows, through a myriad of different mechanisms, communication be-
tween tasks. In a virtualized system, Inter-Partition Communication mechanisms
implement the communication between the different subsystems referenced above.
TrustZone technology has been in the forefront of hardware-assisted security
and it has been explored for virtualization purposes, since natively it provides sep-
aration between two execution worlds while enforcing, by design, different privi-
lege to these execution worlds. LTZVisor, an open-source lightweight TrustZone-
assisted hypervisor, emerged as a way of providing a platform for exploring how
TrustZone can be exploited to assist virtualization. Its IPC mechanism, TZ-
VirtIO, constitutes a standard virtual I/O approach for achieving communication
between the OSes, but some overhead is caused by the introduction of the mech-
anism. Hardware-based solutions are yet to be explored with this solution, which
could bring performance and security benefits while diminishing overhead.
Attending the reasons mentioned above, hTZ-VirtIO was developed as a way
to explore the offloading of the software-based communication mechanism of the
LTZVisor to hardware-based mechanisms.Atualmente, onde a tecnologia e a Internet das Coisas (IoT) dominam a so-
ciedade, os sistemas embebidos são omnipresentes no nosso dia-a-dia, e embora
possam diferir entre as funcionalidades e objetivos finais, todos partilham os mes-
mos requisitos básicos. Seja um sistema não crítico, como um smartphone, ou
um sistema crítico, como uma unidade de controlo de um veículo moderno, estes
requisitos devem ser cumpridos de maneira a se obter um sistema confiável.
Uma tecnologia bem estabelecida para resolver este problema é a virtualiza-
ção. Esta abordagem providencia isolamento através do encapsulamento de sub-
sistemas em máquinas virtuais separadas, além de permitir a partilha de recursos
de hardware. No entanto, estes subsistemas isolados podem ter a necessidade de
comunicar entre si. Comunicação entre tarefas está presente na maioria das pilhas
de software de qualquer sistema e representa uma parte crucial dos mesmos. Num
sistema virtualizado, os mecanismos de comunicação entre-partições implementam
a comunicação entre os diferentes subsistemas mencionados acima.
A tecnologia TrustZone tem estado na vanguarda da segurança assistida por
hardware, e tem sido explorada na implementação de sistemas virtualizados, visto
que permite nativamente a separação entre dois mundos de execução, e impondo
ao mesmo tempo, por design, privilégios diferentes a esses mundos de execução. O
LTZVisor, um hypervisor em código-aberto de baixo overhead assistido por Trust-
Zone, surgiu como uma forma de fornecer uma plataforma que permite a explo-
ração da TrustZone como tecnologia de assistência a virtualização. O TZ-VirtIO,
mecanismo de comunicação do LTZVisor, constitui uma abordagem padrão de
E/S virtuais, para permitir comunicação entre os sistemas operativos. No entanto,
a introdução deste mecanismo provoca sobrecarga sobre o hypervisor. Soluções
baseadas em hardware para o TZ-VirtIO ainda não foram exploradas, e podem
trazer benefícios de desempenho e segurança, e diminuir a sobrecarga.
Atendendo às razões mencionadas acima, o hTZ-VirtIO foi desenvolvido como
uma maneira de explorar a migração do mecanismo de comunicação baseado em
software do LTZVisor para mecanismos baseados em hardware
TCG based approach for secure management of virtualized platforms: state-of-the-art
There is a strong trend shift in the favor of adopting virtualization to get business benefits. The provisioning of virtualized enterprise resources is one kind of many possible scenarios. Where virtualization promises clear advantages it also poses new security challenges which need to be addressed to gain stakeholders confidence in the dynamics of new environment. One important facet of these challenges is establishing 'Trust' which is a basic primitive for any viable business model. The Trusted computing group (TCG) offers technologies and mechanisms required to establish this trust in the target platforms. Moreover, TCG technologies enable protecting of sensitive data in rest and transit. This report explores the applicability of relevant TCG concepts to virtualize enterprise resources securely for provisioning, establish trust in the target platforms and securely manage these virtualized Trusted Platforms
lLTZVisor: a lightweight TrustZone-assisted hypervisor for low-end ARM devices
Dissertação de mestrado em Engenharia Eletrónica Industrial e ComputadoresVirtualization is a well-established technology in the server and desktop space
and has recently been spreading across different embedded industries. Facing
multiple challenges derived by the advent of the Internet of Things (IoT) era,
these industries are driven by an upgrowing interest in consolidating and isolating
multiple environments with mixed-criticality features, to address the complex IoT
application landscape. Even though this is true for majority mid- to high-end
embedded applications, low-end systems still present little to no solutions proposed
so far.
TrustZone technology, designed by ARM to improve security on its processors,
was adopted really well in the embedded market. As such, the research community
became active in exploring other TrustZone’s capacities for isolation, like
an alternative form of system virtualization. The lightweight TrustZone-assisted
hypervisor (LTZVisor), that mainly targets the consolidation of mixed-criticality
systems on the same hardware platform, is one design example that takes advantage
of TrustZone technology for ARM application processors. With the recent
introduction of this technology to the new generation of ARM microcontrollers, an
opportunity to expand this breakthrough form of virtualization to low-end devices
arose.
This work proposes the development of the lLTZVisor hypervisor, a refactored
LTZVisor version that aims to provide strong isolation on resource-constrained
devices, while achieving a low-memory footprint, determinism and high efficiency.
The key for this is to implement a minimal, reliable, secure and predictable virtualization
layer, supported by the TrustZone technology present on the newest
generation of ARM microcontrollers (Cortex-M23/33).Virtualização é uma tecnologia já bem estabelecida no âmbito de servidores e
computadores pessoais que recentemente tem vindo a espalhar-se através de várias
indústrias de sistemas embebidos. Face aos desafios provenientes do surgimento
da era Internet of Things (IoT), estas indústrias são guiadas pelo crescimento
do interesse em consolidar e isolar múltiplos sistemas com diferentes níveis de
criticidade, para atender ao atual e complexo cenário aplicativo IoT. Apesar de
isto se aplicar à maioria de aplicações embebidas de média e alta gama, sistemas
de baixa gama apresentam-se ainda com poucas soluções propostas.
A tecnologia TrustZone, desenvolvida pela ARM de forma a melhorar a segurança
nos seus processadores, foi adoptada muito bem pelo mercado dos sistemas embebidos.
Como tal, a comunidade científica começou a explorar outras aplicações
da tecnologia TrustZone para isolamento, como uma forma alternativa de virtualização
de sistemas. O "lightweight TrustZone-assisted hypervisor (LTZVisor)",
que tem sobretudo como fim a consolidação de sistemas de criticidade mista na
mesma plataforma de hardware, é um exemplo que tira vantagem da tecnologia
TrustZone para os processadores ARM de alta gama. Com a recente introdução
desta tecnologia para a nova geração de microcontroladores ARM, surgiu uma
oportunidade para expandir esta forma inovadora de virtualização para dispositivos
de baixa gama.
Este trabalho propõe o desenvolvimento do hipervisor lLTZVisor, uma versão
reestruturada do LTZVisor que visa em proporcionar um forte isolamento em dispositivos
com recursos restritos, simultâneamente atingindo um baixo footprint de
memória, determinismo e alta eficiência. A chave para isto está na implementação
de uma camada de virtualização mínima, fiável, segura e previsível, potencializada
pela tecnologia TrustZone presente na mais recente geração de microcontroladores
ARM (Cortex-M23/33)
Intel TDX Demystified: A Top-Down Approach
Intel Trust Domain Extensions (TDX) is a new architectural extension in the
4th Generation Intel Xeon Scalable Processor that supports confidential
computing. TDX allows the deployment of virtual machines in the
Secure-Arbitration Mode (SEAM) with encrypted CPU state and memory, integrity
protection, and remote attestation. TDX aims to enforce hardware-assisted
isolation for virtual machines and minimize the attack surface exposed to host
platforms, which are considered to be untrustworthy or adversarial in the
confidential computing's new threat model. TDX can be leveraged by regulated
industries or sensitive data holders to outsource their computations and data
with end-to-end protection in public cloud infrastructure.
This paper aims to provide a comprehensive understanding of TDX to potential
adopters, domain experts, and security researchers looking to leverage the
technology for their own purposes. We adopt a top-down approach, starting with
high-level security principles and moving to low-level technical details of
TDX. Our analysis is based on publicly available documentation and source code,
offering insights from security researchers outside of Intel
ON OPTIMIZATIONS OF VIRTUAL MACHINE LIVE STORAGE MIGRATION FOR THE CLOUD
Virtual Machine (VM) live storage migration is widely performed in the data cen- ters of the Cloud, for the purposes of load balance, reliability, availability, hardware maintenance and system upgrade. It entails moving all the state information of the VM being migrated, including memory state, network state and storage state, from one physical server to another within the same data center or across different data centers. To minimize its performance impact, this migration process is required to be transparent to applications running within the migrating VM, meaning that ap- plications will keep running inside the VM as if there were no migration operations at all.
In this dissertation, a thorough literature review is conducted to provide a big picture of the VM live storage migration process, its problems and existing solutions. After an in-depth examination, we observe that a severe IO interference between the VM IO threads and migration IO threads exists and causes both types of the IO threads to suffer from performance degradation. This interference stems from the fact that both types of IO threads share the same critical IO path by reading from and writing to the same shared storage system. Owing to IO resource contention and requests interference between the two different types of IO requests, not only will the IO request queue lengthens in the storage system, but the time-consuming disk seek operations will also become more frequent. Based on this fundamental observation, this dissertation research presents three related but orthogonal solutions that tackle the IO interference problem in order to improve the VM live storage migration performance.
First, we introduce the Workload-Aware IO Outsourcing scheme, called WAIO, to improve the VM live storage migration efficiency. Second, we address this problem by proposing a novel scheme, called SnapMig, to improve the VM live storage migration efficiency and eliminate its performance impact on user applications at the source server by effectively leveraging the existing VM snapshots in the backup servers. Third, we propose the IOFollow scheme to improve both the VM performance and migration performance simultaneously. Finally, we outline the direction for the future research work.
Advisor: Hong Jian
Trusted Computing and Secure Virtualization in Cloud Computing
Large-scale deployment and use of cloud computing in industry
is accompanied and in the same time hampered by concerns regarding protection of
data handled by cloud computing providers. One of the consequences of moving
data processing and storage off company premises is that organizations have
less control over their infrastructure. As a result, cloud service (CS) clients
must trust that the CS provider is able to protect their data and
infrastructure from both external and internal attacks. Currently however, such
trust can only rely on organizational processes declared by the CS
provider and can not be remotely verified and validated by an external party.
Enabling the CS client to verify the integrity of the host where the
virtual machine instance will run, as well as to ensure that the virtual
machine image has not been tampered with, are some steps towards building
trust in the CS provider. Having the tools to perform such
verifications prior to the launch of the VM instance allows the CS
clients to decide in runtime whether certain data should be stored- or calculations
should be made on the VM instance offered by the CS provider.
This thesis combines three components -- trusted computing, virtualization technology
and cloud computing platforms -- to address issues of trust and
security in public cloud computing environments. Of the three components,
virtualization technology has had the longest evolution and is a cornerstone
for the realization of cloud computing. Trusted computing is a recent
industry initiative that aims to implement the root of trust in a hardware
component, the trusted platform module. The initiative has been formalized
in a set of specifications and is currently at version 1.2. Cloud computing
platforms pool virtualized computing, storage and network resources in
order to serve a large number of customers customers that use a multi-tenant
multiplexing model to offer on-demand self-service over broad network.
Open source cloud computing platforms are, similar to trusted computing, a
fairly recent technology in active development.
The issue of trust in public cloud environments is addressed
by examining the state of the art within cloud computing security and
subsequently addressing the issues of establishing trust in the launch of a
generic virtual machine in a public cloud environment. As a result, the thesis
proposes a trusted launch protocol that allows CS clients
to verify and ensure the integrity of the VM instance at launch time, as
well as the integrity of the host where the VM instance is launched. The protocol
relies on the use of Trusted Platform Module (TPM) for key generation and data protection.
The TPM also plays an essential part in the integrity attestation of the
VM instance host. Along with a theoretical, platform-agnostic protocol,
the thesis also describes a detailed implementation design of the protocol
using the OpenStack cloud computing platform.
In order the verify the implementability of the proposed protocol, a prototype
implementation has built using a distributed deployment of OpenStack.
While the protocol covers only the trusted launch procedure using generic
virtual machine images, it presents a step aimed to contribute towards
the creation of a secure and trusted public cloud computing environment
Enhancing Trust and Resource Allocation in Telecommunications Cloud
Network Functions Virtualization (NFV) has brought the telecommunications industry multiple benefits; however, it has also introduced many new security issues. This thesis tackles security issues related to NFV trust and defines trust as confidence in the integrity of the software and hardware in a system. Existing NFV trust solutions have added trust to the NFV infrastructure with boot time measurements, placement of Virtualized Network Functions (VNFs) on trusted infrastructure and integrity checks of a small set of VNF operations.
This thesis implements the introduced trust elements from existing solutions and proposes several extensions. These extensions enable trust in the NFV management software with run time measurements, introduces a new method for building VNF trust, extends the number of trusted VNF operations and increases the user auditability of trust decisions.
The proposed extensions are designed, implemented and evaluated in a trusted NFV cloud environment. Although the proposed extensions create a more trusted cloud, they come at a steep performance cost to VNF operations. However, the most impacted VNF operations only affect the cloud provider and not the telecommunications consumer.
This thesis offers a valuable contribution to NFV clouds where increased trust is more important than maximized performance or where VNF operations are rarely performed
Software-Defined Cloud Computing: Architectural Elements and Open Challenges
The variety of existing cloud services creates a challenge for service
providers to enforce reasonable Software Level Agreements (SLA) stating the
Quality of Service (QoS) and penalties in case QoS is not achieved. To avoid
such penalties at the same time that the infrastructure operates with minimum
energy and resource wastage, constant monitoring and adaptation of the
infrastructure is needed. We refer to Software-Defined Cloud Computing, or
simply Software-Defined Clouds (SDC), as an approach for automating the process
of optimal cloud configuration by extending virtualization concept to all
resources in a data center. An SDC enables easy reconfiguration and adaptation
of physical resources in a cloud infrastructure, to better accommodate the
demand on QoS through a software that can describe and manage various aspects
comprising the cloud environment. In this paper, we present an architecture for
SDCs on data centers with emphasis on mobile cloud applications. We present an
evaluation, showcasing the potential of SDC in two use cases-QoS-aware
bandwidth allocation and bandwidth-aware, energy-efficient VM placement-and
discuss the research challenges and opportunities in this emerging area.Comment: Keynote Paper, 3rd International Conference on Advances in Computing,
Communications and Informatics (ICACCI 2014), September 24-27, 2014, Delhi,
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