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Copyright Siemens AG 2010. All rights reserved.

Corporate Technology

Architecture of the Kernel!ased"irtual #achine $K"#%

Jan Kiszka, Siemens AG, CT T DE IT 1

Corporate Competence Center Embedded Linux

an!kiszka"siemens!com

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Agenda

&ntroduction

'asic K"# model

#emory

A(&

)ptimi*ations

(aravirtual devices

)utloo+

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"irtuali*ation of Commodity Computers

C(,

##,

&nstructionSet

Cloc+s-

Timers

'usses

-&) /evices

&nterrupt

Controllers

#emory

)nChipesources

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"irtuali*ing the 3 &nstruction Set Architecture

3 originally virtuali*ation 4unfriendly5

.o *ard/are pro0isions

Instructions be*a0e dierent# dependin+ on pri0i#e+e context

2erormance suered on trap&and&emu#ate

CISC nature comp#icates instruction rep#acements

6arly approaches to 3 virtuali*ation

3inar trans#ation 4e!+! 56/are7

Execute substitution code or pri0i#e+ed +uest code

6a re8uire substantia# rep#acements to preser0e i##usion

C29 para0irtua#ization 4e!+ :en7

Guest is a/are o instruction restrictions

;per0isor pro0ides rep#acement ser0ices 4*perca##s7

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7ard8areassisted 3 C(, "irtuali*ation

T8o variants

Inte#>s 5irtua#ization Tec*no#o+, 5T&x

A6D&5 4aka Secure 5irtua# 6ac*ine7

&dentical core concept

C(,($1

%

7ostState

GuestState

"C(,921

0

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Advent and 6volution of K"#

&ntroduced to ma+e "TA#/" availa!le to user space

Exposes 0irtua#ization eatures secure#

Interace@ de0k0m

#erged :uic+ly

A0ai#ab#e since $!?!$% 4$%%?7 Brom irst LK6L postin+ to mer+e@ ( mont*s

ne reason@ ori+ina## 1%% ort*o+ona# to core kerne#

6volved significantly since then

2orted to urt*er arc*itectures 4s('%, 2o/er2C, IA?-7

A#/as /it* #atest x? 0irtua#ization eatures 3ecame reco+nized F dri0in+ part o Linux

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The K"# #odel

(rocesses can create

virtual machines

"#s can contain

6emor

5irtua# C29s In&kerne# de0ice mode#s

Guest physical memory part of

creating process; address space

"C(,s run in processeecution contets

2rocess usua## maps

5C29s on t*reads

7ypervisor

(rocess

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Architectural Advantages of the K"# #odel

(roimity of guest and user space hypervisor

n# one address space s/itc*@ +uest H *ost

Less resc*edu#in+

#assive t /*at t*is7

I stacks

2o/er mana+ement

;ost C29 *ot&p#u++in+

#assive

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"C(, 6ecution =lo8 $K"# "ie8%

6ecute nativeguest code

un,pdatecontet>

raise &?s

Save 7ost>

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K"# #emory #odel

Slot!ased guest memory

6aps +uest p*sica# to

*ost 0irtua# memor

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K"# A(& )vervie8

Step B1 open dev+vm

Three groups of &)CT

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'asic K"# &)CT

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)ptimi*ations of K"#

7ard8are evolves :uic+ly

.ear&nati0e perormance in +uest mode

Decreasin+ costs o mode s/itc*es

Additiona# eatures a0oid sot/are so#utions, t*us exits

.ested pa+e tab#es

TL3 ta++in+A2IC 0irtua#ization

!!!

Fhat 8ill continue to consume cycles

Code pat* bet/een 56&exit and 56&entr 6ode s/itc*es, i!e! t*e need to exit at a##

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)ptimi*ing

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(aravirtual /evices

Advantages

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An Almost&nKernel /evice

vhostnet

Goal high throughput

lo8 latency guest net8or+ing

A0oid *ea0 exits

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Fhat;s net

Generic

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Than+s you for listeningH

?uestions