qemu-kvm

qemu-kvm

[Baruch Even]

Can the Qemu built with KVM support run without KVM? Froma quick perusal
of the kvm.patch it seems that there are places where USE_KVM implies a
qemu-panic without any runtime conditionals.

I'd like to push the KVM patches to Debian Qemu and need to know if they
need to create new executables or just continue to build the existing
ones. To me it seems the former.

Cheers,
Baruch

-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642

Re: qemu-kvm

[Simon Kagstrom]

At Tue, 14 Nov 2006 09:26:01 +0200,
Baruch Even wrote:
> 
> Can the Qemu built with KVM support run without KVM? Froma quick perusal
> of the kvm.patch it seems that there are places where USE_KVM implies a
> qemu-panic without any runtime conditionals.

There is the -no-kvm option which you can pass when starting qemu.

// Simon

-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642

Re: qemu-kvm

[Avi Kivity]

Baruch Even wrote:
> Can the Qemu built with KVM support run without KVM? Froma quick perusal
> of the kvm.patch it seems that there are places where USE_KVM implies a
> qemu-panic without any runtime conditionals.
>   

qemu-kvm.patch is an older release.  With the new release, it should be 
possible to run without kvm.  Let me know (or better, send patches) if 
there are any such places in kvm-2.

> I'd like to push the KVM patches to Debian Qemu and need to know if they
> need to create new executables or just continue to build the existing
> ones. To me it seems the former.
>
>   




-- 
error compiling committee.c: too many arguments to function


-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642

Re: qemu-kvm

[Simon Kagstrom]

At Tue, 14 Nov 2006 10:50:23 +0200,
Avi Kivity wrote:
> 
> Baruch Even wrote:
> > Can the Qemu built with KVM support run without KVM? Froma quick perusal
> > of the kvm.patch it seems that there are places where USE_KVM implies a
> > qemu-panic without any runtime conditionals.
> 
> qemu-kvm.patch is an older release.  With the new release, it should be 
> possible to run without kvm.  Let me know (or better, send patches) if 
> there are any such places in kvm-2.

One thing I've thought about (and quickly hacked on) is to "detect"
the presense of KVM and use it if it is there and use "plain" qemu if
it is not. The question is if this is behavior that the rest of you
would like, I'll send a patch if so.

One thing which I've changed is to return errors from libkvm instead
of directly exiting. Personally I think this behavior is preferred
since it does not force decisions upon the program using the library.

// Simon

-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642

Re: qemu-kvm

[Baruch Even]

* Simon Kagstrom <simon.kagstrom-6Uc+yI3S9P8@public.gmane.org> [061114 11:30]:
> At Tue, 14 Nov 2006 10:50:23 +0200,
> Avi Kivity wrote:
> > 
> > Baruch Even wrote:
> > > Can the Qemu built with KVM support run without KVM? Froma quick perusal
> > > of the kvm.patch it seems that there are places where USE_KVM implies a
> > > qemu-panic without any runtime conditionals.
> > 
> > qemu-kvm.patch is an older release.  With the new release, it should be 
> > possible to run without kvm.  Let me know (or better, send patches) if 
> > there are any such places in kvm-2.
> 
> One thing I've thought about (and quickly hacked on) is to "detect"
> the presense of KVM and use it if it is there and use "plain" qemu if
> it is not. The question is if this is behavior that the rest of you
> would like, I'll send a patch if so.

That would be best IMO. In this way qemu will just work and it can run
(much?) faster if the user has kvm. Though this means some loss in
branding for kvm as users are less likely to know they are running under
kvm.

In usch a mode the user should be notified if KVM is not found and if
KVM is found but the machine doesn't have VT support. Though I guess the
KVM module will fail to load if there is no VT support in the CPU.

Cheers,
Baruch

-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642

Re: qemu-kvm

[Avi Kivity]

Simon Kagstrom wrote:
> At Tue, 14 Nov 2006 10:50:23 +0200,
> Avi Kivity wrote:
>   
>> Baruch Even wrote:
>>     
>>> Can the Qemu built with KVM support run without KVM? Froma quick perusal
>>> of the kvm.patch it seems that there are places where USE_KVM implies a
>>> qemu-panic without any runtime conditionals.
>>>       
>> qemu-kvm.patch is an older release.  With the new release, it should be 
>> possible to run without kvm.  Let me know (or better, send patches) if 
>> there are any such places in kvm-2.
>>     
>
> One thing I've thought about (and quickly hacked on) is to "detect"
> the presense of KVM and use it if it is there and use "plain" qemu if
> it is not. The question is if this is behavior that the rest of you
> would like, I'll send a patch if so.
>   

I think it is indeed desirable.  Please send the patch.

Of course, -no-kvm should not use kvm even if it there.


> One thing which I've changed is to return errors from libkvm instead
> of directly exiting. Personally I think this behavior is preferred
> since it does not force decisions upon the program using the library.
>   

The exit()s are a hack, of course.


-- 
error compiling committee.c: too many arguments to function


-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642

qemu-kvm

[Alberich de megres]

Hi!!

I got a curious situation that leads me to start sailing on qemu-kvm
source code.

I got an audio latency very very high, even with some little cuts at
playback. In qemu lists they told me qemu is synchronous, so if it
take so long to draw high screen resolution audio could be affected.
As I saw, qemu uses sdl to draw guest screen on host computer, my
question is: when sdl draw it uses some kind of 2d acceleration?

Woulld it be hard to make for example screen draw asynchronously to
audio playback? where would be a good point to start look for how to
do it?

Thanks!

Re: qemu-kvm

[Markus Breitländer]

You can alter the sound driver settings by setting some variables before
starting the VM.

I use the following in my start scripts:

export QEMU_AUDIO_DRV=alsa
export QEMU_AUDIO_DAC_FIXED_FREQ=48000
export QEMU_AUDIO_ADC_FIXED_FREQ=48000
export QEMU_ALSA_DAC_BUFFER_SIZE=4096

Maybe this helps?

Greets,
  Markus

Am 13.02.2010 13:39, schrieb Alberich de megres:
> Hi!!
> 
> I got a curious situation that leads me to start sailing on qemu-kvm
> source code.
> 
> I got an audio latency very very high, even with some little cuts at
> playback. In qemu lists they told me qemu is synchronous, so if it
> take so long to draw high screen resolution audio could be affected.
> As I saw, qemu uses sdl to draw guest screen on host computer, my
> question is: when sdl draw it uses some kind of 2d acceleration?
> 
> Woulld it be hard to make for example screen draw asynchronously to
> audio playback? where would be a good point to start look for how to
> do it?
> 
> Thanks!
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: qemu-kvm

[Alberich de megres]

Thanks Markus!
I will try it, and tell you.

Another question: when sdl draw guest OS uses some kind of 2d
acceleration on host side?

2010/2/13 Markus Breitländer <breitlaender@stud.fh-dortmund.de>:
> You can alter the sound driver settings by setting some variables before
> starting the VM.
>
> I use the following in my start scripts:
>
> export QEMU_AUDIO_DRV=alsa
> export QEMU_AUDIO_DAC_FIXED_FREQ=48000
> export QEMU_AUDIO_ADC_FIXED_FREQ=48000
> export QEMU_ALSA_DAC_BUFFER_SIZE=4096
>
> Maybe this helps?
>
> Greets,
>  Markus
>
> Am 13.02.2010 13:39, schrieb Alberich de megres:
>> Hi!!
>>
>> I got a curious situation that leads me to start sailing on qemu-kvm
>> source code.
>>
>> I got an audio latency very very high, even with some little cuts at
>> playback. In qemu lists they told me qemu is synchronous, so if it
>> take so long to draw high screen resolution audio could be affected.
>> As I saw, qemu uses sdl to draw guest screen on host computer, my
>> question is: when sdl draw it uses some kind of 2d acceleration?
>>
>> Woulld it be hard to make for example screen draw asynchronously to
>> audio playback? where would be a good point to start look for how to
>> do it?
>>
>> Thanks!
>> --
>> To unsubscribe from this list: send the line "unsubscribe kvm" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: qemu-kvm

[Alberich de megres]

2010/2/13 Markus Breitländer <breitlaender@stud.fh-dortmund.de>:
> You can alter the sound driver settings by setting some variables before
> starting the VM.
>
> I use the following in my start scripts:
>
> export QEMU_AUDIO_DRV=alsa
> export QEMU_AUDIO_DAC_FIXED_FREQ=48000
> export QEMU_AUDIO_ADC_FIXED_FREQ=48000
> export QEMU_ALSA_DAC_BUFFER_SIZE=4096
>
> Maybe this helps?
>
> Greets,
>  Markus
>

sorry, this didn't improve nothing. I still got the same latency and
audio cuts on playbacks.

If i low resolution on guest machine, then everything works perfect.
What makes me think it could something with graphic on host side.. am
i saying something stupid?

thansk!!

> Am 13.02.2010 13:39, schrieb Alberich de megres:
>> Hi!!
>>
>> I got a curious situation that leads me to start sailing on qemu-kvm
>> source code.
>>
>> I got an audio latency very very high, even with some little cuts at
>> playback. In qemu lists they told me qemu is synchronous, so if it
>> take so long to draw high screen resolution audio could be affected.
>> As I saw, qemu uses sdl to draw guest screen on host computer, my
>> question is: when sdl draw it uses some kind of 2d acceleration?
>>
>> Woulld it be hard to make for example screen draw asynchronously to
>> audio playback? where would be a good point to start look for how to
>> do it?
>>
>> Thanks!
>> --
>> To unsubscribe from this list: send the line "unsubscribe kvm" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>