[Qemu-devel] Disk I/O in QEMU

[Qemu-devel] Disk I/O in QEMU

[Le Tan]

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Hi, I am now studying the disk I/O in QEMU, but I know little about QEMU. I
want to know how QEMU implements or emulates the disk I/O? Where to find
some materials about this? And if I can get all the disk I/O request from
the guest in QEMU? Thanks!

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Re: [Qemu-devel] Disk I/O in QEMU

[Stefan Hajnoczi]

On Tue, Mar 11, 2014 at 03:08:52PM +0800, Le Tan wrote:
> Hi, I am now studying the disk I/O in QEMU, but I know little about QEMU. I
> want to know how QEMU implements or emulates the disk I/O? Where to find
> some materials about this? And if I can get all the disk I/O request from
> the guest in QEMU? Thanks!

QEMU emulates hardware including IDE or SCSI controllers.  I/O requests
go through QEMU.  Look at hw/block/.

Stefan

Re: [Qemu-devel] Disk I/O in QEMU

[Le Tan]

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Hi Stefan,
Thanks for your help. I find that the source code of qemu-1.2.0 doesn't
have hw/block/. So I download the qemu-1.6.2. However it doesn't work. I
run the configure like this:
./configure --enable-kvm --x86_64-softmmu
then make and make install.
I can start the vm using this command:
qemu-system-x86_64 -m 1024 -smp 2 -hda my.img
But the qemu is not using the kvm to accelerate. Then I add the
"-enable-kvm" in the command. I connect to the vm via VNC. However, the
vnc-viewer is just black and displays nothing.
It used to work fine with qemu-1.2.0 (qemu-kvm). Of course, with qemu-kvm,
there is no need to add the "-enable-kvm" option.
So with qemu-1.6.2, did I miss any options?
Thanks!


2014-03-11 20:23 GMT+08:00 Stefan Hajnoczi <stefanha@gmail.com>:

> On Tue, Mar 11, 2014 at 03:08:52PM +0800, Le Tan wrote:
> > Hi, I am now studying the disk I/O in QEMU, but I know little about
> QEMU. I
> > want to know how QEMU implements or emulates the disk I/O? Where to find
> > some materials about this? And if I can get all the disk I/O request from
> > the guest in QEMU? Thanks!
>
> QEMU emulates hardware including IDE or SCSI controllers.  I/O requests
> go through QEMU.  Look at hw/block/.
>
> Stefan
>

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Re: [Qemu-devel] Disk I/O in QEMU

[Fam Zheng]

On Wed, 03/12 20:27, Le Tan wrote:
> Hi Stefan,
> Thanks for your help. I find that the source code of qemu-1.2.0 doesn't
> have hw/block/. So I download the qemu-1.6.2. However it doesn't work. I
> run the configure like this:
> ./configure --enable-kvm --x86_64-softmmu
> then make and make install.
> I can start the vm using this command:
> qemu-system-x86_64 -m 1024 -smp 2 -hda my.img
> But the qemu is not using the kvm to accelerate. Then I add the
> "-enable-kvm" in the command. I connect to the vm via VNC. However, the
> vnc-viewer is just black and displays nothing.
> It used to work fine with qemu-1.2.0 (qemu-kvm). Of course, with qemu-kvm,
> there is no need to add the "-enable-kvm" option.
> So with qemu-1.6.2, did I miss any options?
> Thanks!
> 

But you didn't specify vnc as display in your command line?

Try specify "-vnc :0" and connect with "vncviewer :0".

Fam

Re: [Qemu-devel] Disk I/O in QEMU

[Le Tan]

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I am sorry I didn't give the complete command I have executed. It is like
this:
qemu-system-x86_64 -m 1024 -smp 2 -hda /home/tanle/study/new.img -nographic
-vnc 192.168.146.118:2  -enable-kvm
If I delete the "-enable-kvm", it is ok and the system can boot up (just
slow). But with "-enable-kvm", the vnc viewer is just black, displaying
nothing.
So did I miss any options? Or there is something else wrong?
Thanks!


2014-03-12 21:13 GMT+08:00 Fam Zheng <famz@redhat.com>:

> On Wed, 03/12 20:27, Le Tan wrote:
> > Hi Stefan,
> > Thanks for your help. I find that the source code of qemu-1.2.0 doesn't
> > have hw/block/. So I download the qemu-1.6.2. However it doesn't work. I
> > run the configure like this:
> > ./configure --enable-kvm --x86_64-softmmu
> > then make and make install.
> > I can start the vm using this command:
> > qemu-system-x86_64 -m 1024 -smp 2 -hda my.img
> > But the qemu is not using the kvm to accelerate. Then I add the
> > "-enable-kvm" in the command. I connect to the vm via VNC. However, the
> > vnc-viewer is just black and displays nothing.
> > It used to work fine with qemu-1.2.0 (qemu-kvm). Of course, with
> qemu-kvm,
> > there is no need to add the "-enable-kvm" option.
> > So with qemu-1.6.2, did I miss any options?
> > Thanks!
> >
>
> But you didn't specify vnc as display in your command line?
>
> Try specify "-vnc :0" and connect with "vncviewer :0".
>
> Fam
>

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