Re: [Qemu-devel] git bisect results: ec757c67c40a56492001487e69272f62144fd124 breaks windows boot in qemu-kvm

[Erik Rull <erik.rull@rdsoftware.de>]

 On February 1, 2012 at 3:42 PM Jan Kiszka <jan.kiszka@siemens.com> wrote:

> On 2012-02-01 15:02, Erik Rull wrote:
> >
> > On February 1, 2012 at 2:40 PM Avi Kivity <avi@redhat.com> wrote:
> >
> >> On 02/01/2012 02:52 PM, Erik Rull wrote:
> >>>  Hi all,
> >>>
> >>> first of all I'm a bit confused:
> >>>
> >>> What is the difference between qemu with command line option
> > --enable-kvm
> >>> and qemu-kvm?
> >>> It seems to be a difference in code so far, from the performance
point
> > of
> >>> view it seems to be the same...
> >>
> >> The differences are being reduced rapidly, thanks to Jan's efforts.
> >> Right now what remains is PIT performance and accuracy, device
> >> assignment, and Windows XP performance.  Most guests should see the
same
> >> performance.
>
> MSI performance is expected to be worse with upstream as well, thus
virtio.
>
> >>
> >>> Now my issue that lead me to a git bisect on qemu-kvm:
> >>> The following commit / merge breaks my windows guest boot sequence
and
> >>> causes resets infinitely:
> >>> ec757c67c40a56492001487e69272f62144fd124 Merge branch
'upstream-merge'
> > into
> >>> next
> >>> Thu, 5 Jan 2012 11:00:07 +0000 (13:00 +0200)    Avi Kivity
> > <avi@redhat.com>
> >>>
> >>>
> >>> Interesting: qemu with --enable-kvm master and the same command line
> >>> options as qemu-kvm runs perfect.
> >>> My command line options are:
> >>> qemu-system-x86_64 -serial /dev/ttyS2 -readconfig
> > /etc/ich9-ehci-uhci.cfg
> >>> -device usb-host,bus=ehci.0 -device usb-tablet -drive
> >>> file=/dev/sda2,cache=off -m 1024 -net nic,macaddr=$MACADDR -net
> >>> tap,script=/etc/qemu-ifup -no-acpi -monitor stdio -L
> > /usr/X11R6/share/qemu
> >>> -boot c -localtime
> >>>
> >>>
> >>
> >> What version of Windows are you using?  What's the contents of
> >> /etc/ich9-ehci-uhci.cfg?
> >>
> >
> > Hi Avi,
> >
> > the contents from the .cfg are located in docs/ich9-ehci-uhci.cfg
> >
> > I tried two versions of Windows XP: One is the default Windows XP SP3
that
> > you get from MSDN, one is Windows Embedded Standard (embedded
customized
> > XP).
> >
> > Both show the same behavior: boots with qemu -enable-kvm and
continuously
> > reboots with qemu-kvm.
>
> What does qemu-kvm with -no-kvm-irqchip do?
>
> Jan
>

Wow - that works!
Does this influence the guest performance?