<s>
QEMU	B-Application
(	O
Quick	O
EMUlator	B-Application
)	O
is	O
a	O
free	B-License
and	I-License
open-source	I-License
emulator	B-Application
.	O
</s>
<s>
It	O
emulates	B-Application
the	O
machine	O
's	O
processor	B-General_Concept
through	O
dynamic	O
binary	O
translation	O
and	O
provides	O
a	O
set	O
of	O
different	O
hardware	O
and	O
device	O
models	O
for	O
the	O
machine	O
,	O
enabling	O
it	O
to	O
run	O
a	O
variety	O
of	O
guest	B-General_Concept
operating	I-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
It	O
can	O
interoperate	O
with	O
Kernel-based	B-Application
Virtual	I-Application
Machine	I-Application
(	O
KVM	B-Application
)	O
to	O
run	O
virtual	O
machines	O
at	O
near-native	O
speed	O
.	O
</s>
<s>
QEMU	B-Application
can	O
also	O
do	O
emulation	B-Application
for	O
user-level	B-Operating_System
processes	O
,	O
allowing	O
applications	O
compiled	O
for	O
one	O
architecture	O
to	O
run	O
on	O
another	O
.	O
</s>
<s>
QEMU	B-Application
was	O
written	O
by	O
Fabrice	O
Bellard	O
and	O
is	O
free	B-Application
software	I-Application
,	O
mainly	O
licensed	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
(	O
GPL	B-License
for	O
short	O
)	O
.	O
</s>
<s>
Various	O
parts	O
are	O
released	O
under	O
the	O
BSD	B-Operating_System
license	I-Operating_System
,	O
GNU	B-Application
Lesser	I-Application
General	I-Application
Public	I-Application
License	I-Application
(	O
LGPL	B-Application
)	O
or	O
other	O
GPL-compatible	O
licenses	O
.	O
</s>
<s>
QEMU	B-Application
has	O
multiple	O
operating	O
modes	O
:	O
</s>
<s>
User-mode	O
emulation	B-Application
In	O
this	O
mode	O
QEMU	B-Application
runs	O
single	O
Linux	B-Application
or	O
Darwin/macOS	O
programs	O
that	O
were	O
compiled	O
for	O
a	O
different	O
instruction	B-General_Concept
set	I-General_Concept
.	O
</s>
<s>
Fast	O
cross-compilation	O
and	O
cross-debugging	O
are	O
the	O
main	O
targets	O
for	O
user-mode	O
emulation	B-Application
.	O
</s>
<s>
System	O
emulation	B-Application
In	O
this	O
mode	O
QEMU	B-Application
emulates	B-Application
a	O
full	O
computer	O
system	O
,	O
including	O
peripherals	O
.	O
</s>
<s>
QEMU	B-Application
can	O
boot	O
many	O
guest	B-General_Concept
operating	I-General_Concept
systems	I-General_Concept
,	O
including	O
Linux	B-Application
,	O
Solaris	B-Application
,	O
Microsoft	B-Application
Windows	I-Application
,	O
DOS	B-Device
,	O
and	O
BSD	B-Operating_System
;	O
it	O
supports	O
emulating	B-Application
several	O
instruction	B-General_Concept
sets	I-General_Concept
,	O
including	O
x86	B-Operating_System
,	O
MIPS	B-Device
,	O
32-bit	O
ARMv7	O
,	O
ARMv8	O
,	O
PowerPC	B-Architecture
,	O
SPARC	B-Architecture
,	O
ETRAX	B-Device
CRIS	I-Device
and	O
MicroBlaze	B-Device
.	O
</s>
<s>
KVM	B-Application
Hosting	O
Here	O
QEMU	B-Application
deals	O
with	O
the	O
setting	O
up	O
and	O
migration	O
of	O
KVM	B-Application
images	O
.	O
</s>
<s>
It	O
is	O
still	O
involved	O
in	O
the	O
emulation	B-Application
of	O
hardware	O
,	O
but	O
the	O
execution	O
of	O
the	O
guest	O
is	O
done	O
by	O
KVM	B-Application
as	O
requested	O
by	O
QEMU	B-Application
.	O
</s>
<s>
Xen	B-Operating_System
Hosting	O
QEMU	B-Application
is	O
involved	O
only	O
in	O
the	O
emulation	B-Application
of	O
hardware	O
;	O
the	O
execution	O
of	O
the	O
guest	O
is	O
done	O
within	O
Xen	B-Operating_System
and	O
is	O
totally	O
hidden	O
from	O
QEMU	B-Application
.	O
</s>
<s>
QEMU	B-Application
can	O
save	O
and	O
restore	O
the	O
state	O
of	O
the	O
virtual	O
machine	O
with	O
all	O
programs	O
running	O
.	O
</s>
<s>
Guest	B-General_Concept
operating	I-General_Concept
systems	I-General_Concept
do	O
not	O
need	O
patching	O
in	O
order	O
to	O
run	O
inside	O
QEMU	B-Application
.	O
</s>
<s>
QEMU	B-Application
supports	O
the	O
emulation	B-Application
of	O
various	O
architectures	O
,	O
including	O
x86	B-Operating_System
,	O
MIPS64	B-Device
(	O
up	O
to	O
Release	O
6	O
)	O
,	O
SPARC	B-Architecture
(	O
sun4m	O
and	O
sun4u	O
)	O
,	O
ARM	B-Architecture
(	O
Integrator/CP	O
and	O
Versatile/PB	O
)	O
,	O
SuperH	O
,	O
PowerPC	B-Architecture
(	O
PReP	B-Device
and	O
Power	B-Device
Macintosh	I-Device
)	O
,	O
ETRAX	B-Device
CRIS	I-Device
,	O
MicroBlaze	B-Device
,	O
and	O
RISC-V	B-Device
.	O
</s>
<s>
The	O
virtual	O
machine	O
can	O
interface	O
with	O
many	O
types	O
of	O
physical	O
host	O
hardware	O
,	O
including	O
the	O
user	O
's	O
hard	O
disks	O
,	O
CD-ROM	B-Device
drives	O
,	O
network	B-Protocol
cards	I-Protocol
,	O
audio	O
interfaces	O
,	O
and	O
USB	B-Protocol
devices	O
.	O
</s>
<s>
USB	B-Protocol
devices	O
can	O
be	O
completely	O
emulated	B-Application
,	O
or	O
the	O
host	O
's	O
USB	B-Protocol
devices	O
can	O
be	O
used	O
,	O
although	O
this	O
requires	O
administrator	O
privileges	O
and	O
does	O
not	O
work	O
with	O
some	O
devices	O
.	O
</s>
<s>
Virtual	O
disk	B-Application
images	I-Application
can	O
be	O
stored	O
in	O
a	O
special	O
format	O
(	O
qcow	O
or	O
qcow2	O
)	O
that	O
only	O
takes	O
up	O
as	O
much	O
disk	O
space	O
as	O
the	O
guest	O
OS	O
actually	O
uses	O
.	O
</s>
<s>
This	O
way	O
,	O
an	O
emulated	B-Application
120GB	O
disk	O
may	O
occupy	O
only	O
a	O
few	O
hundred	O
megabytes	O
on	O
the	O
host	O
.	O
</s>
<s>
This	O
provides	O
the	O
possibility	O
for	O
reverting	O
the	O
emulated	B-Application
disk	O
's	O
contents	O
to	O
an	O
earlier	O
state	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
base	O
image	O
could	O
hold	O
a	O
fresh	O
install	O
of	O
an	O
operating	B-General_Concept
system	I-General_Concept
that	O
is	O
known	O
to	O
work	O
,	O
and	O
the	O
overlay	O
images	O
are	O
used	O
.	O
</s>
<s>
)	O
,	O
the	O
user	O
can	O
delete	O
the	O
overlay	O
and	O
use	O
an	O
earlier	O
emulated	B-Application
disk	B-Application
image	I-Application
.	O
</s>
<s>
QEMU	B-Application
can	O
emulate	O
network	B-Protocol
cards	I-Protocol
(	O
of	O
different	O
models	O
)	O
which	O
share	O
the	O
host	O
system	O
's	O
connectivity	O
by	O
doing	O
network	O
address	O
translation	O
,	O
effectively	O
allowing	O
the	O
guest	O
to	O
use	O
the	O
same	O
network	O
as	O
the	O
host	O
.	O
</s>
<s>
The	O
virtual	O
network	B-Protocol
cards	I-Protocol
can	O
also	O
connect	O
to	O
network	B-Protocol
cards	I-Protocol
of	O
other	O
instances	O
of	O
QEMU	B-Application
or	O
to	O
local	O
TAP	B-Protocol
interfaces	O
.	O
</s>
<s>
Network	O
connectivity	O
can	O
also	O
be	O
achieved	O
by	O
bridging	O
a	O
TUN/TAP	B-Protocol
interface	O
used	O
by	O
QEMU	B-Application
with	O
a	O
non-virtual	O
Ethernet	O
interface	O
on	O
the	O
host	O
OS	O
using	O
the	O
host	O
OS	O
's	O
bridging	O
features	O
.	O
</s>
<s>
QEMU	B-Application
integrates	O
several	O
services	O
to	O
allow	O
the	O
host	O
and	O
guest	O
systems	O
to	O
communicate	O
;	O
for	O
example	O
,	O
an	O
integrated	O
SMB	B-Operating_System
server	O
and	O
network-port	O
redirection	O
(	O
to	O
allow	O
incoming	O
connections	O
to	O
the	O
virtual	O
machine	O
)	O
.	O
</s>
<s>
It	O
can	O
also	O
boot	O
Linux	B-Operating_System
kernels	I-Operating_System
without	O
a	O
bootloader	O
.	O
</s>
<s>
QEMU	B-Application
does	O
not	O
depend	O
on	O
the	O
presence	O
of	O
graphical	O
output	O
methods	O
on	O
the	O
host	O
system	O
.	O
</s>
<s>
Instead	O
,	O
it	O
can	O
allow	O
one	O
to	O
access	O
the	O
screen	O
of	O
the	O
guest	O
OS	O
via	O
an	O
integrated	O
VNC	B-Protocol
server	I-Protocol
.	O
</s>
<s>
It	O
can	O
also	O
use	O
an	O
emulated	B-Application
serial	B-Protocol
line	I-Protocol
,	O
without	O
any	O
screen	O
,	O
with	O
applicable	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
Simulating	O
multiple	O
CPUs	O
running	O
SMP	B-Operating_System
is	O
possible	O
.	O
</s>
<s>
QEMU	B-Application
does	O
not	O
require	O
administrative	O
rights	O
to	O
run	O
unless	O
additional	O
kernel	B-Application
modules	I-Application
for	O
improving	O
speed	O
(	O
like	O
KQEMU	O
)	O
are	O
used	O
or	O
certain	O
modes	O
of	O
its	O
network	O
connectivity	O
model	O
are	O
utilized	O
.	O
</s>
<s>
The	O
Tiny	O
Code	O
Generator	O
(	O
TCG	O
)	O
aims	O
to	O
remove	O
the	O
shortcoming	O
of	O
relying	O
on	O
a	O
particular	O
version	O
of	O
GCC	B-Application
or	O
any	O
compiler	O
,	O
instead	O
incorporating	O
the	O
compiler	O
(	O
code	O
generator	O
)	O
into	O
other	O
tasks	O
performed	O
by	O
QEMU	B-Application
at	O
run	O
time	O
.	O
</s>
<s>
The	O
whole	O
translation	O
task	O
thus	O
consists	O
of	O
two	O
parts	O
:	O
basic	B-Application
blocks	I-Application
of	O
target	O
code	O
(	O
TBs	O
)	O
being	O
rewritten	O
in	O
TCG	O
ops	O
-	O
a	O
kind	O
of	O
machine-independent	O
intermediate	O
notation	O
,	O
and	O
subsequently	O
this	O
notation	O
being	O
compiled	O
for	O
the	O
host	O
's	O
architecture	O
by	O
TCG	O
.	O
</s>
<s>
If	O
no	O
dedicated	O
JIT	O
code	O
is	O
available	O
for	O
the	O
architecture	O
,	O
TCG	O
falls	O
back	O
to	O
a	O
slow	O
interpreter	B-Application
mode	O
called	O
TCG	O
Interpreter	B-Application
(	O
TCI	O
)	O
.	O
</s>
<s>
Starting	O
with	O
QEMU	B-Application
Version	O
0.10.0	O
,	O
TCG	O
ships	O
with	O
the	O
QEMU	B-Application
stable	O
release	O
.	O
</s>
<s>
It	O
replaces	O
the	O
dyngen	O
,	O
which	O
relied	O
on	O
GCC	B-Application
3.x	O
to	O
work	O
.	O
</s>
<s>
KQEMU	O
was	O
a	O
Linux	B-Application
kernel	I-Application
module	I-Application
,	O
also	O
written	O
by	O
Fabrice	O
Bellard	O
,	O
which	O
notably	O
sped	O
up	O
emulation	B-Application
of	O
x86	B-Operating_System
or	O
x86-64	O
guests	O
on	O
platforms	O
with	O
the	O
same	O
CPU	B-General_Concept
architecture	O
.	O
</s>
<s>
This	O
worked	O
by	O
running	O
user	B-Operating_System
mode	I-Operating_System
code	O
(	O
and	O
optionally	O
some	O
kernel	B-Operating_System
code	O
)	O
directly	O
on	O
the	O
host	O
computer	O
's	O
CPU	B-General_Concept
,	O
and	O
by	O
using	O
processor	B-General_Concept
and	O
peripheral	O
emulation	B-Application
only	O
for	O
kernel-mode	O
and	O
real-mode	B-Application
code	O
.	O
</s>
<s>
KQEMU	O
could	O
execute	O
code	O
from	O
many	O
guest	O
OSes	O
even	O
if	O
the	O
host	O
CPU	B-General_Concept
did	O
not	O
support	O
hardware-assisted	B-General_Concept
virtualization	I-General_Concept
.	O
</s>
<s>
KQEMU	O
was	O
initially	O
a	O
closed-source	B-Application
product	O
available	O
free	O
of	O
charge	O
,	O
but	O
starting	O
from	O
version	O
1.3.0pre10	O
(	O
February	O
2007	O
)	O
,	O
it	O
was	O
relicensed	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
.	O
</s>
<s>
QEMU	B-Application
versions	O
starting	O
with	O
0.12.0	O
(	O
)	O
support	O
large	O
memory	O
which	O
makes	O
them	O
incompatible	O
with	O
KQEMU	O
.	O
</s>
<s>
Newer	O
releases	O
of	O
QEMU	B-Application
have	O
completely	O
removed	O
support	O
for	O
KQEMU	O
.	O
</s>
<s>
QVM86	O
was	O
a	O
GNU	B-License
GPLv2	I-License
licensed	O
drop-in	O
replacement	O
for	O
the	O
then	O
closed-source	B-Application
KQEMU	O
.	O
</s>
<s>
Kernel-based	B-Application
Virtual	I-Application
Machine	I-Application
(	O
KVM	B-Application
)	O
has	O
mostly	O
taken	O
over	O
as	O
the	O
Linux-based	O
hardware-assisted	B-General_Concept
virtualization	I-General_Concept
solution	O
for	O
use	O
with	O
QEMU	B-Application
in	O
the	O
wake	O
of	O
the	O
lack	O
of	O
support	O
for	O
KQEMU	O
and	O
QVM86	O
.	O
</s>
<s>
QEMU	B-Application
can	O
also	O
use	O
KVM	B-Application
on	O
other	O
architectures	O
like	O
ARM	B-Architecture
and	O
MIPS	B-Device
.	O
</s>
<s>
Intel	O
's	O
Hardware	O
Accelerated	O
Execution	O
Manager	O
(	O
HAXM	O
)	O
is	O
an	O
open-source	O
alternative	O
to	O
KVM	B-Application
for	O
x86-based	O
hardware-assisted	B-General_Concept
virtualization	I-General_Concept
on	O
NetBSD	O
,	O
Linux	B-Application
,	O
Windows	O
and	O
macOS	B-Application
using	O
Intel	O
VT	O
.	O
Intel	O
mostly	O
solicits	O
its	O
use	O
with	O
QEMU	B-Application
for	O
Android	B-Application
development	I-Application
.	O
</s>
<s>
Starting	O
with	O
version	O
2.9.0	O
,	O
the	O
official	O
QEMU	B-Application
includes	O
support	O
for	O
HAXM	O
,	O
under	O
the	O
name	O
hax	O
.	O
</s>
<s>
QEMU	B-Application
also	O
supports	O
the	O
following	O
accelerators	O
:	O
</s>
<s>
whpx	O
,	O
Microsoft	O
's	O
Windows	O
Hypervisor	B-Operating_System
Platform	O
based	O
on	O
Intel	O
VT	O
or	O
AMD-V	O
.	O
</s>
<s>
tcg	O
,	O
QEMU	B-Application
's	O
own	O
Tiny	O
Code	O
Generator	O
.	O
</s>
<s>
QEMU	B-Application
supports	O
the	O
following	O
disk	B-Application
image	I-Application
formats	O
:	O
</s>
<s>
CD/DVD	B-General_Concept
images	I-General_Concept
(	O
.iso	B-General_Concept
)	O
that	O
contain	O
sector-by-sector	O
contents	O
of	O
an	O
optical	O
disk	O
(	O
e.g.	O
</s>
<s>
The	O
QEMU	B-Application
Object	O
Model	O
(	O
QOM	O
)	O
provides	O
a	O
framework	O
for	O
registering	O
user	O
creatable	O
types	O
and	O
instantiating	O
objects	O
from	O
those	O
types	O
.	O
</s>
<s>
The	O
MIPS-compatible	O
Loongson-3	O
processor	B-General_Concept
adds	O
200	O
new	O
instructions	O
to	O
help	O
QEMU	B-Application
translate	O
x86	B-Operating_System
instructions	O
;	O
those	O
new	O
instructions	O
lower	O
the	O
overhead	O
of	O
executing	O
x86/CISC	O
-style	O
instructions	O
in	O
the	O
MIPS	B-Device
pipeline	O
.	O
</s>
<s>
With	O
additional	O
improvements	O
in	O
QEMU	B-Application
by	O
the	O
Chinese	O
Academy	O
of	O
Sciences	O
,	O
Loongson-3	O
achieves	O
an	O
average	O
of	O
70%	O
the	O
performance	O
of	O
executing	O
native	O
binaries	O
while	O
running	O
x86	B-Operating_System
binaries	O
from	O
nine	O
benchmarks	O
.	O
</s>
<s>
Virtualization	O
solutions	O
that	O
use	O
QEMU	B-Application
are	O
able	O
to	O
execute	O
multiple	O
virtual	O
CPUs	O
in	O
parallel	O
.	O
</s>
<s>
For	O
user-mode	O
emulation	B-Application
QEMU	B-Application
maps	O
emulated	B-Application
threads	O
to	O
host	O
threads	O
.	O
</s>
<s>
For	O
full	O
system	O
emulation	B-Application
,	O
QEMU	B-Application
is	O
capable	O
of	O
running	O
a	O
host	O
thread	O
for	O
each	O
emulated	B-Application
virtual	O
CPU	B-General_Concept
(	O
vCPU	O
)	O
.	O
</s>
<s>
This	O
is	O
dependent	O
on	O
the	O
guest	O
having	O
been	O
updated	O
to	O
support	O
parallel	O
system	O
emulation	B-Application
,	O
currently	O
ARM	B-Architecture
,	O
Alpha	O
,	O
HP-PA	B-Device
,	O
PowerPC	B-Architecture
,	O
RISC-V	B-Device
,	O
s390x	O
,	O
x86	B-Operating_System
and	O
Xtensa	O
.	O
</s>
<s>
VirtualBox	B-Operating_System
,	O
first	O
released	O
in	O
January	O
2007	O
,	O
used	O
some	O
of	O
QEMU	B-Application
's	O
virtual	B-General_Concept
hardware	I-General_Concept
devices	O
,	O
and	O
had	O
a	O
built-in	O
dynamic	O
recompiler	O
based	O
on	O
QEMU	B-Application
.	O
</s>
<s>
As	O
with	O
KQEMU	O
,	O
VirtualBox	B-Operating_System
runs	O
nearly	O
all	O
guest	O
code	O
natively	O
on	O
the	O
host	O
via	O
the	O
VMM	O
(	O
Virtual	O
Machine	O
Manager	O
)	O
and	O
uses	O
the	O
recompiler	O
only	O
as	O
a	O
fallback	O
mechanism	O
-	O
for	O
example	O
,	O
when	O
guest	O
code	O
executes	O
in	O
real	B-Application
mode	I-Application
.	O
</s>
<s>
In	O
addition	O
,	O
VirtualBox	B-Operating_System
did	O
a	O
lot	O
of	O
code	O
analysis	O
and	O
patching	O
using	O
a	O
built-in	O
disassembler	O
in	O
order	O
to	O
minimize	O
recompilation	O
.	O
</s>
<s>
VirtualBox	B-Operating_System
is	O
free	B-License
and	I-License
open-source	I-License
(	O
available	O
under	O
GPL	B-License
)	O
,	O
except	O
for	O
certain	O
features	O
.	O
</s>
<s>
Xen	B-Operating_System
,	O
a	O
virtual	B-Operating_System
machine	I-Operating_System
monitor	I-Operating_System
,	O
can	O
run	O
in	O
HVM	O
(	O
hardware	B-General_Concept
virtual	I-General_Concept
machine	I-General_Concept
)	O
mode	O
,	O
using	O
Intel	O
VT-x	O
or	O
AMD-V	O
hardware	O
x86	B-General_Concept
virtualization	I-General_Concept
extensions	O
and	O
ARM	B-Application
Cortex-A7	I-Application
and	O
Cortex-A15	O
virtualization	O
extension	O
.	O
</s>
<s>
This	O
means	O
that	O
instead	O
of	O
paravirtualized	O
devices	O
,	O
a	O
real	O
set	O
of	O
virtual	B-General_Concept
hardware	I-General_Concept
is	O
exposed	O
to	O
the	O
domU	B-Operating_System
to	O
use	O
real	O
device	O
drivers	O
to	O
talk	O
to	O
.	O
</s>
<s>
QEMU	B-Application
includes	O
several	O
components	O
:	O
CPU	B-General_Concept
emulators	B-Application
,	O
emulated	B-Application
devices	O
,	O
generic	O
devices	O
,	O
machine	O
descriptions	O
,	O
user	O
interface	O
,	O
and	O
a	O
debugger	O
.	O
</s>
<s>
The	O
emulated	B-Application
devices	O
and	O
generic	O
devices	O
in	O
QEMU	B-Application
make	O
up	O
its	O
device	O
models	O
for	O
I/O	O
virtualization	O
.	O
</s>
<s>
They	O
comprise	O
a	O
PIIX3	O
IDE	O
(	O
with	O
some	O
rudimentary	O
PIIX4	O
capabilities	O
)	O
,	O
Cirrus	O
Logic	O
or	O
plain	O
VGA	O
emulated	B-Application
video	O
,	O
RTL8139	O
or	O
E1000	O
network	O
emulation	B-Application
,	O
and	O
ACPI	O
support	O
.	O
</s>
<s>
APIC	O
support	O
is	O
provided	O
by	O
Xen	B-Operating_System
.	O
</s>
<s>
Xen-HVM	O
has	O
device	O
emulation	B-Application
based	O
on	O
the	O
QEMU	B-Application
project	O
to	O
provide	O
I/O	O
virtualization	O
to	O
the	O
VMs	O
.	O
</s>
<s>
Hardware	O
is	O
emulated	B-Application
via	O
a	O
QEMU	B-Application
"	O
device	O
model	O
"	O
daemon	O
running	O
as	O
a	O
backend	O
in	O
dom0	B-Operating_System
.	O
</s>
<s>
Unlike	O
other	O
QEMU	B-Application
running	O
modes	O
(	O
dynamic	O
translation	O
or	O
KVM	B-Application
)	O
,	O
virtual	O
CPUs	O
are	O
completely	O
managed	O
to	O
the	O
hypervisor	B-Operating_System
,	O
which	O
takes	O
care	O
of	O
stopping	O
them	O
while	O
QEMU	B-Application
is	O
emulating	B-Application
memory-mapped	O
I/O	O
accesses	O
.	O
</s>
<s>
KVM	B-Application
(	O
Kernel-based	B-Application
Virtual	I-Application
Machine	I-Application
)	O
is	O
a	O
FreeBSD	O
and	O
Linux	B-Application
kernel	I-Application
module	I-Application
that	O
allows	O
a	O
user	B-Operating_System
space	I-Operating_System
program	O
access	O
to	O
the	O
hardware	B-General_Concept
virtualization	I-General_Concept
features	O
of	O
various	O
processors	O
,	O
with	O
which	O
QEMU	B-Application
is	O
able	O
to	O
offer	O
virtualization	O
for	O
x86	B-Operating_System
,	O
PowerPC	B-Architecture
,	O
and	O
S/390	O
guests	O
.	O
</s>
<s>
When	O
the	O
target	O
architecture	O
is	O
the	O
same	O
as	O
the	O
host	O
architecture	O
,	O
QEMU	B-Application
can	O
make	O
use	O
of	O
KVM	B-Application
particular	O
features	O
,	O
such	O
as	O
acceleration	O
.	O
</s>
<s>
In	O
early	O
2005	O
,	O
Win4Lin	O
introduced	O
Win4Lin	O
Pro	O
Desktop	O
,	O
based	O
on	O
a	O
'	O
tuned	O
 '	O
version	O
of	O
QEMU	B-Application
and	O
KQEMU	O
and	O
it	O
hosts	O
NT-versions	O
of	O
Windows	O
.	O
</s>
<s>
Win4Lin	O
Virtual	O
Desktop	O
Server	O
serves	O
Microsoft	B-Application
Windows	I-Application
sessions	O
to	O
thin	O
clients	O
from	O
a	O
Linux	B-Application
server	O
.	O
</s>
<s>
In	O
September	O
2006	O
,	O
Win4Lin	O
announced	O
a	O
change	O
of	O
the	O
company	O
name	O
to	O
with	O
the	O
release	O
of	O
Win4BSD	O
Pro	O
Desktop	O
,	O
a	O
port	O
of	O
the	O
product	O
to	O
FreeBSD	O
and	O
PC-BSD	O
.	O
</s>
<s>
Solaris	B-Application
support	O
followed	O
in	O
May	O
2007	O
with	O
the	O
release	O
of	O
Win4Solaris	O
Pro	O
Desktop	O
and	O
Win4Solaris	O
Virtual	O
Desktop	O
Server	O
.	O
</s>
<s>
SerialICE	O
is	O
a	O
QEMU-based	O
firmware	O
debugging	O
tool	O
running	O
system	O
firmware	O
inside	O
of	O
QEMU	B-Application
while	O
accessing	O
real	O
hardware	O
through	O
a	O
serial	O
connection	O
to	O
a	O
host	O
system	O
.	O
</s>
<s>
This	O
can	O
be	O
used	O
as	O
a	O
cheap	O
replacement	O
for	O
hardware	O
in-circuit	B-Application
emulators	I-Application
(	O
ICE	O
)	O
.	O
</s>
<s>
WinUAE	B-Device
introduced	O
support	O
for	O
the	O
CyberStorm	B-Operating_System
PPC	I-Operating_System
and	I-Operating_System
Blizzard	I-Operating_System
603e	I-Operating_System
boards	I-Operating_System
using	O
the	O
QEMU	B-Application
PPC	O
core	O
in	O
version	O
3.0.0	O
.	O
</s>
<s>
Unicorn	O
is	O
a	O
CPU	B-General_Concept
emulation	B-Application
framework	O
based	O
on	O
QEMU	B-Application
's	O
"	O
TCG	O
"	O
CPU	B-General_Concept
emulator	B-Application
.	O
</s>
<s>
Unlike	O
QEMU	B-Application
,	O
Unicorn	O
focuses	O
on	O
the	O
CPU	B-General_Concept
only	O
:	O
no	O
emulation	B-Application
of	O
any	O
peripherals	O
is	O
provided	O
and	O
raw	O
binary	O
code	O
(	O
outside	O
of	O
the	O
context	O
of	O
an	O
executable	O
file	O
or	O
a	O
system	O
image	O
)	O
can	O
be	O
run	O
directly	O
.	O
</s>
<s>
Besides	O
the	O
CPU	B-General_Concept
(	O
which	O
is	O
also	O
configurable	O
and	O
can	O
emulate	O
a	O
number	O
of	O
Intel	O
CPU	B-General_Concept
models	O
including	O
(	O
as	O
of	O
3	O
March	O
2018	O
)	O
Sandy	B-Device
Bridge	I-Device
,	O
Ivy	B-Device
Bridge	I-Device
,	O
Haswell	B-Device
,	O
Broadwell	B-General_Concept
and	O
Skylake	B-Architecture
)	O
,	O
the	O
following	O
devices	O
are	O
emulated	B-Application
:	O
</s>
<s>
The	O
BIOS	B-Operating_System
implementation	O
used	O
by	O
QEMU	B-Application
starting	O
from	O
version	O
0.12	O
is	O
SeaBIOS	B-Language
.	O
</s>
<s>
The	O
VGA	O
BIOS	B-Operating_System
implementation	O
comes	O
from	O
Plex86/Bochs	O
.	O
</s>
<s>
The	O
UEFI	B-Architecture
firmware	I-Architecture
for	O
QEMU	B-Application
is	O
OVMF	O
.	O
</s>
<s>
QEMU	B-Application
emulates	B-Application
the	O
following	O
PowerMac	B-Device
peripherals	O
:	O
</s>
<s>
Two	O
PMAC-IDE-Interfaces	O
with	O
hard	O
disk	O
and	O
CD-ROM	B-Device
support	O
.	O
</s>
<s>
VIA-CUDA	O
with	O
ADB	B-Device
keyboard	B-Device
and	O
mouse	B-Device
.	O
</s>
<s>
OpenBIOS	B-Device
is	O
used	O
as	O
the	O
firmware	O
.	O
</s>
<s>
QEMU	B-Application
emulates	B-Application
the	O
following	O
PREP	B-Device
peripherals	O
:	O
</s>
<s>
On	O
the	O
PREP	B-Device
target	O
,	O
Open	O
Hack'Ware	O
,	O
an	O
Open-Firmware-compatible	O
BIOS	B-Operating_System
,	O
is	O
used	O
.	O
</s>
<s>
QEMU	B-Application
can	O
emulate	O
the	O
paravirtual	O
sPAPR	O
interface	O
with	O
the	O
following	O
peripherals	O
:	O
</s>
<s>
PCI	O
bridge	O
,	O
for	O
access	O
to	O
virtio	B-Application
devices	O
,	O
VGA-compatible	O
graphics	O
,	O
USB	B-Protocol
,	O
etc	O
.	O
</s>
<s>
On	O
the	O
sPAPR	O
target	O
,	O
another	O
Open-Firmware-compatible	O
BIOS	B-Operating_System
is	O
used	O
,	O
called	O
SLOF	O
.	O
</s>
<s>
QEMU	B-Application
emulates	B-Application
the	O
ARMv7	O
instruction	B-General_Concept
set	I-General_Concept
(	O
and	O
down	O
to	O
ARMv5TEJ	O
)	O
with	O
NEON	O
extension	O
.	O
</s>
<s>
It	O
emulates	B-Application
full	O
systems	O
like	O
Integrator/CP	O
board	O
,	O
Versatile	O
baseboard	O
,	O
RealView	O
Emulation	B-Application
baseboard	O
,	O
XScale-based	O
PDAs	O
,	O
Palm	O
Tungsten|E	O
PDA	O
,	O
Nokia	B-Application
N800	I-Application
and	O
Nokia	B-Language
N810	I-Language
Internet	O
tablets	O
etc	O
.	O
</s>
<s>
QEMU	B-Application
also	O
powers	O
the	O
Android	B-Application
emulator	I-Application
which	O
is	O
part	O
of	O
the	O
Android	B-Application
SDK	I-Application
(	O
most	O
current	O
Android	O
implementations	O
are	O
ARM-based	O
)	O
.	O
</s>
<s>
Starting	O
from	O
version	O
2.0.0	O
of	O
their	O
Bada	O
SDK	O
,	O
Samsung	O
has	O
chosen	O
QEMU	B-Application
to	O
help	O
development	O
on	O
emulated	B-Application
'	O
Wave	O
 '	O
devices	O
.	O
</s>
<s>
In	O
1.5.0	O
and	O
1.6.0	O
Samsung	O
Exynos	O
4210	O
(	O
dual-core	O
Cortex	B-Application
a9	I-Application
)	O
and	O
Versatile	O
Express	O
ARM	B-Application
Cortex-A9	I-Application
ARM	B-Architecture
Cortex-A15	O
are	O
emulated	B-Application
.	O
</s>
<s>
In	O
1.6.0	O
,	O
the	O
32-bit	O
instructions	O
of	O
the	O
ARMv8	O
(	O
AARCH64	O
)	O
architecture	O
are	O
emulated	B-Application
,	O
but	O
64-bit	O
instructions	O
are	O
unsupported	O
.	O
</s>
<s>
QEMU	B-Application
has	O
support	O
for	O
both	O
32	O
-	O
and	O
64-bit	O
SPARC	B-Architecture
architectures	O
.	O
</s>
<s>
When	O
the	O
firmware	O
in	O
the	O
JavaStation	B-Device
(	O
sun4m-Architecture	O
)	O
became	O
version	O
0.8.1	O
Proll	O
,	O
a	O
PROM	B-General_Concept
replacement	O
used	O
in	O
version	O
0.8.2	O
,	O
was	O
replaced	O
with	O
OpenBIOS	B-Device
.	O
</s>
<s>
QEMU	B-Application
emulates	B-Application
the	O
following	O
sun4m/sun4c/sun4d	O
peripherals	O
:	O
</s>
<s>
Emulating	B-Application
Sun4u	O
(	O
UltraSPARC	O
PC-like	O
machine	O
)	O
,	O
Sun4v	B-General_Concept
(	O
T1	O
PC-like	O
machine	O
)	O
,	O
or	O
generic	O
Niagara	B-General_Concept
(	O
T1	O
)	O
machine	O
with	O
the	O
following	O
peripherals	O
:	O
</s>
