[Qemu-devel] In-kernel emulation

[Qemu-devel] In-kernel emulation

[Xin Tong]

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I am wondering that whether there are any attempts (product-oriented or
research-based ) to push QEMU into the Linux kernel to speed up emulation.
If the emulation is running in the kernel, there are some resources it can
manipulate to speed up emulation in comparison to the when it is running as
a user process, i.e. MMU. Also, IO emulation may become faster, because 2
kernel enters and exits are incurred for a network packet if QEMU is running
as a user process. If QEMU is running in the kernel, only 1 kernel enter and
exit are needed.  Any suggestions or discussions are welcome.


Thanks

Xin

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Re: [Qemu-devel] In-kernel emulation

[陳韋任]

> I am wondering that whether there are any attempts (product-oriented or
> research-based ) to push QEMU into the Linux kernel to speed up emulation.
> If the emulation is running in the kernel, there are some resources it can
> manipulate to speed up emulation in comparison to the when it is running as
> a user process, i.e. MMU. Also, IO emulation may become faster, because 2
> kernel enters and exits are incurred for a network packet if QEMU is running
> as a user process. If QEMU is running in the kernel, only 1 kernel enter and
> exit are needed.  Any suggestions or discussions are welcome.

  You want to use QEMU to emulate guest ISA different from the host?
If the ISA of guest and host is the same, then KVM is enough, I think.

Regards,
chenwj

-- 
Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667

Re: [Qemu-devel] In-kernel emulation

[陳韋任]

> guest isa is different from host isa in this case.
> 
> Xin
> 
> On Fri, Oct 7, 2011 at 12:33 PM, 陳韋任 <chenwj@iis.sinica.edu.tw> wrote:
> 
> > > I am wondering that whether there are any attempts (product-oriented or
> > > research-based ) to push QEMU into the Linux kernel to speed up emulation.
> > > If the emulation is running in the kernel, there are some resources it can
> > > manipulate to speed up emulation in comparison to the when it is running as
> > > a user process, i.e. MMU. Also, IO emulation may become faster, because 2

  I would like to know how you can leverage linux kernel to speed up
MMU/IO emulation if guest and host are different ISAs. :)

> > > kernel enters and exits are incurred for a network packet if QEMU is running
> > > as a user process. If QEMU is running in the kernel, only 1 kernel enter and
> > > exit are needed.  Any suggestions or discussions are welcome.
> >
> >   You want to use QEMU to emulate guest ISA different from the host?
> > If the ISA of guest and host is the same, then KVM is enough, I think.


-- 
Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667

Re: [Qemu-devel] In-kernel emulation

[Xin Tong]

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I am kind of speculating here. I could be wrong


MMU. in the kernel you can manipulate the EPT reg which is normally used by
kvm ( introduced by intel vmx, or amd svm).

IO, specifically for network packets, they do not need to go to user space,
they can be handled to the virtual machine directly.


Thanks


Xin


On Fri, Oct 7, 2011 at 3:10 PM, 陳韋任 <chenwj@iis.sinica.edu.tw> wrote:

> > guest isa is different from host isa in this case.
> >
> > Xin
> >
> > On Fri, Oct 7, 2011 at 12:33 PM, 陳韋任 <chenwj@iis.sinica.edu.tw> wrote:
> >
> > > > I am wondering that whether there are any attempts (product-oriented
> or
> > > > research-based ) to push QEMU into the Linux kernel to speed up
> emulation.
> > > > If the emulation is running in the kernel, there are some resources
> it can
> > > > manipulate to speed up emulation in comparison to the when it is
> running as
> > > > a user process, i.e. MMU. Also, IO emulation may become faster,
> because 2
>
>   I would like to know how you can leverage linux kernel to speed up
> MMU/IO emulation if guest and host are different ISAs. :)
>
> > > > kernel enters and exits are incurred for a network packet if QEMU is
> running
> > > > as a user process. If QEMU is running in the kernel, only 1 kernel
> enter and
> > > > exit are needed.  Any suggestions or discussions are welcome.
> > >
> > >   You want to use QEMU to emulate guest ISA different from the host?
> > > If the ISA of guest and host is the same, then KVM is enough, I think.
>
>
> --
> Wei-Ren Chen (陳韋任)
> Computer Systems Lab, Institute of Information Science,
> Academia Sinica, Taiwan (R.O.C.)
> Tel:886-2-2788-3799 #1667
>

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