Download - Virtualization a Limitless World

8/2/2019 Virtualization a Limitless World

1/6

)Abstract:

Virtuali

suchas

Theusu

overall

)Introducti

Inthep

Oneop

machin

eachoth

were:

Virtuali

Robert

Machin

thetypi

Ashep

nonpri

privilag

softwar

instructi

softwar

Virtuali

thissoft

systems

operati

machin

switchin

Support

machin

ation,inco

ahardware

algoalofvir

ardwarere

on:

ast

ratingsyste

.Variousap

er.Machine

Lowserver

Overallincr

ationera

.Goldberg

sResearch.

Virtualma

calthirdgen

intsout,su

ilegedmod

dmodethe

nucleus(a

ionsormak

nucleusin

ationisaso

warelayerd

.The

Virtual

gsystems.

cannowh

gbehindsc

ingmultiple

canhostse

irtuali

puting,ist

platform,op

tualizationi

sourceutiliz

mononem

plicationsw

utilisation

tilization,a

aseinhard

escribesth

Hesaid:

hinesyste

erationarch

hsystemsh

.Inprivileg

yarenot.T

ologustok

supervisor

ordertoha

ftwarelayer

oesistodiv

izationLaye

achOShas

stanumbe

nes.

instanceso

veralLinux/

ation:

ecreation

eratingsyst

tocentraliz

ation.

achine,sot

ouldrunon

asverylow

nd

arecost,e

thenstate

swere

origi

itecturesan

adadualst

dmodealli

eo.sprovid

rnel).User

calls e.g.,

eprivileged

inbetween

idethereso

ris

in

charg

theillusiont

rofoperatin

Operating

Windowcop

ALimi

favirtual(

em,astorag

eadministr

heOShadc

thatmachin

,mosttime

c.

ofthingsin

nallydevelo

dMultipro

atehardwar

instructions

esasmallr

programsc

SVC's (anal

functions

themachin

urcesofthe

ofmultiple

hatitcontr

gsystemsb

ystems:Ho

ies.

less

atherthan

edeviceor

tivetasks

mpletecon

e,butthese

itwasbelo

his1974pa

pedto

corre

rammingo

eorganizati

areavailabl

sidentprog

uldexecute

logoustosy

.g.,I/O pe

andtheop

machinea

xingthe

har

lsthecomp

ecausethe

ogeneous

orld

ctual)versi

etworkres

hileimprovi

trolofther

application

25%.Othe

ertitledSu

ctsome

of

t

eratingsyst

naprivil

totheappl

amcalledt

thenonpri

temcalls)t

rformedon

eratingsyst

ongallthe

wareresou

letehardwa

irtualization

orHeteroge

nofsomet

urces.

ingscalabilit

esourcesin

scouldaffe

rdisadvanta

veyofVirtu

heshortco

emse.g. O

gedmode

licationwhil

eprivilege

vilegedhard

theprivile

theirbehalf

em.Essentia

guestopera

rcesto

seve

rebut,infa

layermake

neous,one

ing,

yand

hat

t

ges

al

ingsof

/360.

nda

innon

ware

ed

.

llywhat

ing

ral

t,the

sallthe

hysical


2/6

)Hardware

x86mo

Thepro

Thegre

Thefig.

(reservecriticals

softwar

Thepro

fromac

process

Tocarry

recogni

Curre

task.Iti

privilegchanges

level.

Descri

theDPL

executi

compar

DPLisin

Reque

selector

withth

accesst

ofsuffic

CPL,the

doesno

privileg

Privileg

segmen

control

followin

Virtual

Eachvir

thepri

TheVM

Specificatio

es:Privilag

cessorsseg

ternumber

showshow

d

for

the

moftware,us

.(Systems

cessoruses

essingase

rdetectsa

outprivileg

esthefollo

tprivilegel

sstoredinb

level

of

thetheCPLwh

ptorprivileg

fieldofthe

gcodeseg

dtotheCP

terpreteddi

stedprivile

s.Itisstore

CPLtodete

oasegment

ientprivileg

RPLoverrid

taccessase

sforthats

levelsarec

tregister.T

amongcode

gsections.

achineM

tualmachin

arylinkbet

Mprimarily:

Presentse

IsolatesVM

ns:

elevels

entprotec

smeanless

heselevels

st

privilegeallytheker

hatuseonl

rivilegelev

mentwith

privilegelev

elevelchec

ingthreet

vel(CPL)

its0and1o

code

segmenprogram

elevel(DPL)

egmentor

entattemp

LandRPLof

ifferently,d

elevel(RPL

inbits0an

rmineifacc

hassufficie

elevel.That

estheCPL,

gmentonb

gment.

heckedwhe

echecksus

segments;t

nitor

interfaces

eenaVM

ulatedhard

fromtheh

tionmecha

rprivileges.

ofprivilege

code,

datanelofanop

2ofthe4p

lstopreve

greaterpri

elviolation,

ksbetween

pesofprivil

TheCPList

ftheCSand

nt

from

whcontrolistr

TheDPL

atedescrip

tstoaccess

thesegmen

pendingon

TheRPL

d1ofthese

esstoaseg

tprivileget

is,iftheRP

ndvicever

halfofana

nthesegme

edfordata

herefore,th

ithits

host

ndthehost

waretothe

ostOSandf

ismrecogni

anbeinter

,

and

stacks)ratingsyst

ossibleprivi

taprogram

ilege,exce

itgenerates

codesegme

legelevels:

heprivilege

SSsegment

ich

instructinsferredto

istheprivil

orforthes

asegment

torgatesel

thetypeof

isanoverri

gmentsele

entisallo

oaccessth

ofasegme

a.TheRPL

pplicationp

ntselector

ccessdiffer

etwokinds

systemvia

OSandhar

virtualmac

romeachot

zes4privile

retedasrin

is

used

for

m.Outerrin

legelevelss

ortaskope

tundercon

ageneralp

ntsanddata

levelofthe

registers.N

ns

are

beinacodeseg

gelevelof

gmentorg

rgate,the

ector(asde

segmentor

eprivilegel

tor.Thepro

ed.Evenif

segment,a

ntselectori

anbeused

rogramunle

fasegmen

fromthose

ofaccesses

hevirtual

m

ware,theV

ine

her

elevels,nu

gsofprotec

he

segmentgsareused

houldusele

ratingatal

rolledsitua

rotectionex

segments,t

currentlyex

ormally,the

fetched.

Tentwitha

segmento

te.Whent

PLofthese

cribedlater

atebeinga

evelthatis

cessorchec

heprogram

ccessisdeni

numericall

oinsureth

sstheprogr

descriptori

sedfortra

areconsider

achinemon

MMprovid

mberedfro

tion.Thece

s

containingforlesscriti

vels0and3

sserprivile

tions.When

ception(#G

heprocesso

ecutingpro

CPLisequa

e

processoifferentpri

gate.Itiss

ecurrently

gmentorga

inthissecti

ccessed.

ssignedtos

kstheRPLal

ortaskreq

ediftheRP

greaterth

tprivileged

amitselfha

isloadedint

sfersofpro

edseparate

itor(VMM).

sacrucialr

0to3.

ter

the

al

.)

elevel

the

).

r

ramor

ltothe

ilege

oredin

teis

on).The

egment

ong

esting

isnot

nthe

code

access

oa

gram

lyinthe

Being

ole.


3/6

ThrottlesindividualVMaccesstosystemresources,preventinganunstableVMfrom

impactingsystemperformance

PasseshardwareinstructionstoandfromtheVMandthehostOS/hypervisorWhenfullvirtualizationisemployed,theVMMwillpresentacompletesetofemulatedhardwareto

theVM'sguestoperatingsystem.ThisincludestheCPU,motherboard,memory,disk,diskcontroller,

andnetworkcards.Forexample,MicrosoftVirtualServer2005emulatesanIntel21140NICcardand

Intel440BXchipset.Regardlessoftheactualphysicalhardwareonthehostsystem,theemulated

hardware

remains

the

same.

ThenextsignificantroleoftheVMMistoprovideisolation.TheVMMhasfullcontrolofthephysical

hostsystem'sresources,leavingindividualvirtualmachineswithaccessonlytotheiremulated

hardwareresources.TheVMMcontainsnomechanismsforinterVMcommunication,thusrequiring

thattwovirtualmachineswishingtoexchangedatadosooverthenetwork.

AnothermajorroleoftheVMMistomanagehostsystemresourceaccess.Thisisimportant,asit

canpreventoverutilizationofoneVMfromstarvingouttheperformanceofotherVMsonthesame

host.Throughthesystemconfigurationconsole,systemhardwareresourcessuchastheCPU,

network,anddiskaccesscanbethrottled,withmaximumusagepercentagesassignedtoeach

individualVM.ThisallowstheVMMtoproperlyscheduleaccesstohostsystemresourcesaswellas

toguaranteethatcriticalVMswillhaveaccesstotheamountofhardwareresourcestheyneedto

sustain

their

operations.

ClassicallytherearetwotypesofVMM.

AtypeIIVMMisonethatrunsontopofahostingoperatingsystemandthenspawnshigherlevelvirtualmachines. ExamplesoftypeIIVMMsincludetheJavaVMand.Netenvironment. These

VMMsmonitortheirvirtualmachinesandredirectrequestsforresourcetoappropriateAPIsinthe

hostingenvironment(withsomelevelofprocessinginbetween).

AtypeIVMMisonethatrunsdirectlyonthehardwarewithouttheneedofahostingoperatingsystem. TypeIVMMsarealsoknownas'hypervisors' sotheonlytruedifferencebetweenaVMM

andahypervisoriswhereitruns. Thefunctionalityprovidedbybothisequitable. ExamplesoftypeI

VMMsincludethemainframevirtualizationsolutionsofferedbycompaniessuchasAmdahland

IBM,andonmoderncomputersbysolutionslikeVMwareESX,XenandWindowsvirtualization.

HypervisorTheprimaryroleofthehypervisoristoworkwiththeVMMtocoordinateaccesstothephysicalhost

system'shardwareresources.ThisincludesschedulingaccesstotheCPUaswellasthedriversfor

communicationwiththephysicaldevicesonthehost,suchasitsnetworkcards.

Thetermhypervisorisusedtodescribealightweightoperatingshellthathasthesolepurposeof

providingVMhostingservices.ThehypervisordiffersfromatraditionalOSinthattheOSmaybe

designedforotherrolesonthenetwork.AsitistailoredtoVMhosting,ahypervisorsolution

generallyoffersbetterperformanceandshouldhavefewersecurityvulnerabilitiesbecauseitruns

fewservicesandcontainsonlyessentialcode.Hypervisorswrittenforhardwareassisted

virtualizationcanembedthemselvesmuchdeeperintothesystemarchitectureandoffersuperior

performanceimprovementsasaresult.

LikeanytraditionalOS,ahypervisorbasedOSstillcontainsitsownoperatingsystemcode;

therefore,maintainingsecurityupdatesisstillimportant.UnlikeatraditionalOS,hypervisorsare

vendorspecific,soanyneededhypervisorpatchesorsecurityupdateswillcomedirectlyfromthe

virtualizationsoftwarevendor.Becausehypervisorsarevendorcentric,individualdevicesupport

oftencomesdirectlyfromthevirtualizationvendors.Hence,itisimportantfortheorganizationto

ensurethatanyplannedvirtualizationproductsarecompatiblewithitsexistingorplannedsystem

hardware.WhenhostingVMsonatraditionalOSsuchasSUSELinuxEnterpriseServerorWindows

ServerLonghorn,theorganizationwillfindthatwhilethehostOShasalargerfootprintthana

hypervisor,it

does

provide

additional

flexibility

with

hardware

devices.

Bothhypervisorsandoperatingsystemshavetheirstrengthsandweaknesses.Operatingsystems

providegreaterdevicesupportthanhypervisors,butalsorequireattentiontoensurethattheyare

currentonallpatchesandsecurityupdates.Hypervisorsrunonminimaldiskandstorageresources,

butpatchesanddevicedriversmustcomedirectlyfromthevirtualizationsoftwarevendor.


4/6

VMMv

Therea

Machin

monitor

theVM

provide

Compar

Operati

whichis

deviced

Inavirt

anddev

VMMru

theVM

access.I

wouldn

paravirt

)Generatio

Basedo

categori

Full

fullvirt

environ

virtualiz

several

memor

machin

capable

operati

standal

Para

paravi

machin

modifie

operati

virtualiz

guest(s)

thevirt

may

allfromth

machin

Hypervisor

reanumber

Monitor'.

ingandenf

keepstra

resources,

ingTraditio

gsystemsd

wherethey

riveraccess

alizedenvir

icedrivers.

nsallVMsa

mustprov

Iftheguest

otbeneces

ualizationc

nsofVirtua

ntheextent

esbasedon

irtualizatio

ualizationis

ent,namel

ationrequir

irtualmach

access,and

,andthatis

ofexecutio

gsystems.

oneusecan

Virtualizati

tualizationi

sthatissim

dinterfacei

nswhichar

edenviron

andhostto

aldomain(

w

thevirtuavirtualdo

executioni

ofdifferent

Inthesimpl

rcingpolicy

kofeveryth

redirects

th

alx86Arch

esignedfor

runprivileg

tosystemh

onment,th

achVMcan

tRing1.Be

idetranslati

Skerneldi

aryandthu

mesintopl

lization

ofvirtualiz

theirgener

,

avirtualiza

ly,onethati

sthatever

inesinclu

whatevero

intendedt

ontheraw

heobvious

successfull

n,

savirtualiza

ilarbutnoti

toreducet

esubstantia

ent.Thepa

requestand

hereexec

l

machine

aintotheh

nsidethevi

programsa

stterms t

onthevirtu

inghappeni

virtual

ma

itecturean

x86/x64en

edOSinstru

ardware.Ap

VMMruns

notbegive

auseprivile

oninorder

notdeman

sperforman

y.

tion,thew

tions:

iontechniq

sacomplet

salientfea

ingthefulli

therelemen

runinavir

hardwarec

testofvirtu

runinside

tiontechniq

denticaltot

heportion

llymorediff

ravirtualizati

acknowled

tionperfor

onitor(VMostdomain)

tualguest

ndimpleme

eVMMist

almachines

nginsideof

hine

to

res

Virtualize

ironments

ctions.Privil

plicationsr

atRing0al

fullaccess

gedinstructi

otrickth

dRing0acc

cewouldim

rldofvirtu

eusedtop

simulation

ureoftheh

nstructions

tsareused

ualmachin

anberunin

lizationis

virtualma

uethatpres

hatoftheu

ftheguest'

iculttoruni

ionprovides

ethesetas

anceiswo

)

to

be

sim,and/orred

ntationstha

epieceofs

forwhichit

avirtualma

urces,

or

de

ResourceA

rewrittent

egedinstru

natRing3.

ngwiththe

oRing0wi

ionswithint

guestinto

essinthefir

provesubst

izationisdi

rovideacer

oftheunde

ardwarebe

et,input/ou

bythesoftw

.Insuchan

thevirtual

hetherano

hine.

entsasoftw

nderlyingha

execution

navirtuale

speciallyde

s,whichw

se).Asucce

pler

(by

reloucetheove

usethem

oftwareres

isresponsib

hine,and

nies

access

ccess

havefulla

tionsinclud

hostoperat

houtinduci

heguestex

elievingth

stplace,the

antially.Thi

idedintoth

ainkindof

rlyinghard

reflectedint

putoperati

arethatrun

environme

achineand

peratingsys

areinterfac

rdware.The

imespentp

vironment

fined'hook

uldotherwi

ssfulparavir

cating

execuallperform

niker'Virtu

onsiblefor

le. Thisme

hennecess

o

resources

ccesstoRin

eOSkernel

ingsystem's

gconflicts,

ecttoruna

tithasRing

nthetransl

iswhere

reemajor

irtualmach

are.Full

ooneof

ons,interru

sonthebar

t,anysoftw

,inparticul

temintende

etovirtual

intentofth

erforming

comparedt

'toallowth

sebeexecu

tualizedpla

tion

of

critiancedegrad

l

nsthat

ry

.

0,

nd

kernel

sothe

tRing0,

0

tion

ne

ts,

e

are

r,any

dfor

anon

e

edin

form

al

tasks

ationof


5/6

Hard

hardw

virtualiz

virtualiz

unmodi

comple

V)in

20

ithard

5)Concl

We

sce

Wi

Ne

asp

Referen

Website

1)http:

2)http:

3)http:

4)http:

5)http:

6)

www

Papers:

XenPaul BarhAlex Ho,

wareassiste

areassisted

ationusing

ationisuse

iedguesto

eisolation.

6.Hardwararevirtual

usion

cantakevir

nerios,itss

hvariousty

worketc,it

ectoflife.

ces:

s:

/www.kern

/blogs.msd

/en.wikiped

/en.wikiped

/en.wikiped

.vmware.co

nd theam_, Boris Draolf Neugebaue

dvirtualizat

virtualizati

elpfromha

tosimulate

eratingsyst

Hardwarea

assisted

vi

achine(HV

tualization

copeisund

pesofvirtu

application

lthread.co

.com/b/virt

ia.org/wiki/

ia.org/wiki/

ia.org/wiki/

rt of Virovic, Keir Frasry, Ian Pratt, A

ion.

nisaplatfo

rdwarecap

acomplete

em(usingth

sistedvirtu

tualizationi

M),VirtualI

saneverlas

ubtedlyexp

lizationslik

andecono

/publicatio

ual_pc_guy

irtualizatio

86_virtuali

Operating_s

tualizatir, Steven Han

drew War_eld

rmvirtualiz

bilities,pri

hardwaree

esameinst

lizationwa

salso

know

oncallsitn

tingtechnol

ectedtobe

Hardware,

icnature

ns/virtualiza

archive/20

n

zation

ystemlevel

n, Tim Harris,

tionapproa

arilyfromt

nvironment,

uctionseta

addedtox

asaccelertivevirtuali

ogyandwit

omeexpon

Desktop,M

illdefinitely

tion/

6/07/10/66

virtualizati

chthatenab

hehostpro

orvirtualm

thehostm

6processor

tedvirtuali

zation.

theadvan

ntially mor

mory,Soft

bringtheb

1958.aspx

n

lesefficient

essors.Full

achine,inw

achine)exe

s(IntelVTx

ation;Xenca

ementinot

ewidespre

are,Dataa

onspreadi

full

hichan

utesin

rAMD

lls

her

d.

nd

every


6/6

University of Cambridge Computer Laboratory15 JJ Thomson Avenue, Cambridge, UK, CB3 0FD

[email protected]

Personalthanksto:

1)Mr.Saurabh Singh(BrainSoft,Noida)

2)Mr.Abhay

Verma

(IT

VIII

Semester,

AKGEC)

SubmittedBy:

AnkurVerma

B.TechVISemester

Emailid:[email protected]

Contact:8860016877

ComputerScienceEngineeringDepartment

AjayKumarGargEngineeringCollege

Ghaziabad

Digitally signed by Ankur

Verma

Date: 2012.04.30 07:50:14

+05'30'

Download - Virtualization a Limitless World

Top Related