Re: [Qemu-devel] Problem with QEMU on KVM

[Gerhard Wiesinger]

On Mon, 12 Apr 2010, Jamie Lokier wrote:

> Mulyadi Santosa wrote:
> > Hi Gerhard...
> >
> > On Sun, Apr 11, 2010 at 20:52, Gerhard Wiesinger <address@hidden> wrote:
> > > OK, uses the following ports:
> > > Port 0x20: 8259 interrupt controller
> > > Port 0x40: 8253 timer
> > >
> > > Interrupt 0x1A:
> > > ah=0x00: fetches system timer counters
> > > ah=0x02: reads the clock
> > > ah=0x04: fetches date
> > >
> > > So there must be something wrong with KVM with the above functionality (I
> > > guess the timers).
> >
> > Hmm, my silly guess is, maybe the timer is seen as decremented....or
> > at least "stuck".
> >
> > I have very little knowledge about git, but maybe you can start doing
> > git bisect to narrow which git commit that introduce such behaviour.
> > Meanwhile, let's wait for comments from one of the KVM developers.
>
> There are various -no-kvm-XXX options to try:
>
> -no-kvm-irqchip disable KVM kernel mode PIC/IOAPIC/LAPIC
> -no-kvm-pit     disable KVM kernel mode PIT
> -no-kvm-pit-reinjection disable KVM kernel mode PIT interrupt reinjection
>
> Any of them might be causing this problem.
>
> They disable in-kernel emulation of the interrupt controller and timer
> chips, and force the qemu version to be used.  It's possible the
> in-kernel emulation is buggier than the qemu version.

Hello Jamie, thanx so far.

I'm starting in this way:
/root/download/qemu/qemu-0.12.3/x86_64-softmmu/qemu-system-x86_64 -enable-kvm 
-a_lot_of_other_options

All options you mentioned don't work:
/root/download/qemu/qemu-0.12.3/x86_64-softmmu/qemu-system-x86_64: invalid 
option -- '-no-kvm-irqchip'
/root/download/qemu/qemu-0.12.3/x86_64-softmmu/qemu-system-x86_64: invalid 
option -- '-no-kvm-pit'
/root/download/qemu/qemu-0.12.3/x86_64-softmmu/qemu-system-x86_64: invalid 
option -- '-no-kvm-no-kvm-irqchip'

Is there another way of startup or is it working only on newer versions?

BTW: For me it is very unclear what's the difference between the 
following commands:
qemu
qemu -enable-kvm
kvm

How can I build the kvm executable? Different source tree? Newer version 
from branch?

Maybe someone can explain the different versions of qemu/kvm and branches 
etc. and possible features in detail.

Thnx.

Ciao,
Gerhard

--
http://www.wiesinger.com/