[Qemu-devel] Infinite IRQ injection when trying windows 10

[Qemu-devel] Infinite IRQ injection when trying windows 10

[//-//ani Nemati]

Hi,

Recently I was trying windows 10 on top of Qemu-KVM and I saw  4% of CPU is
being used all the time even when the windows VM is idle. I tested it for
nested VM (Linux(L0)->Linux(L1)->windows(L2)) and I saw CPU usage increased
upto 45%. I traced my host and I saw there is an infinite interrupt loop
which injected by qemu main process to my windows VM. I also traced the
windows machine and I saw System process is handling that interrupt. The
main qemu process injects IRQ 209 periodically. I wonder if it is a
bug!!!!!

Cheers,
Hani

Re: [Qemu-devel] Infinite IRQ injection when trying windows 10

[Dr. David Alan Gilbert]

* //-//ani  Nemati (hani.nemati@gmail.com) wrote:
> Hi,
> 
> Recently I was trying windows 10 on top of Qemu-KVM and I saw  4% of CPU is
> being used all the time even when the windows VM is idle. I tested it for
> nested VM (Linux(L0)->Linux(L1)->windows(L2)) and I saw CPU usage increased
> upto 45%. I traced my host and I saw there is an infinite interrupt loop
> which injected by qemu main process to my windows VM. I also traced the
> windows machine and I saw System process is handling that interrupt. The
> main qemu process injects IRQ 209 periodically. I wonder if it is a
> bug!!!!!

What's the qemu commandline you're using and what version of qemu?
Also, what host hardware?

Dave

> Cheers,
> Hani
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

Re: [Qemu-devel] Infinite IRQ injection when trying windows 10

[//-//ani Nemati]

/usr/bin/qemu-system-x86_64 -name win10 -S -machine
pc-i440fx-2.6,accel=kvm,usb=off -cpu Haswell -m 2048 -realtime mlock=off
-smp 2,sockets=2,cores=1,threads=1 -uuid
9b3b910d-f3d1-494e-9471-943fc511d994 -no-user-config -nodefaults -chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/win10.monitor,server,nowait
-mon chardev=charmonitor,id=monitor,mode=control -rtc
base=localtime,driftfix=slew -global kvm-pit.lost_tick_policy=discard
-no-hpet -no-shutdown -global PIIX4_PM.disable_s3=1 -global
PIIX4_PM.disable_s4=1 -boot strict=on -device
ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x5.0x7 -device
ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x5
-device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x5.0x1
-device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x5.0x2
-drive
file=/home/hani/external1/win10.img,if=none,id=drive-ide0-0-0,format=qcow2
-device
ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1
-netdev tap,fd=24,id=hostnet0 -device
rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:6c:0a:a3,bus=pci.0,addr=0x3
-chardev pty,id=charserial0 -device
isa-serial,chardev=charserial0,id=serial0 -device usb-tablet,id=input0 -vnc
127.0.0.1:0 -device VGA,id=video0,vgamem_mb=16,bus=pci.0,addr=0x2 -device
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 -msg timestamp=on

Qemu version: 2.5
Linux kernel: 4.2
CPU: Interl i7-4790 CPU @3.60GHz
Memory: Kingston DDR3-1600 MHz, 32G

On Wed, Oct 19, 2016 at 2:59 PM, Dr. David Alan Gilbert <dgilbert@redhat.com
> wrote:

> * //-//ani  Nemati (hani.nemati@gmail.com) wrote:
> > Hi,
> >
> > Recently I was trying windows 10 on top of Qemu-KVM and I saw  4% of CPU
> is
> > being used all the time even when the windows VM is idle. I tested it for
> > nested VM (Linux(L0)->Linux(L1)->windows(L2)) and I saw CPU usage
> increased
> > upto 45%. I traced my host and I saw there is an infinite interrupt loop
> > which injected by qemu main process to my windows VM. I also traced the
> > windows machine and I saw System process is handling that interrupt. The
> > main qemu process injects IRQ 209 periodically. I wonder if it is a
> > bug!!!!!
>
> What's the qemu commandline you're using and what version of qemu?
> Also, what host hardware?
>
> Dave
>
> > Cheers,
> > Hani
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>



-- 
<<<<<<<    /-/ /\ /\/ / /\/ *E* /\/\ /\ *T* /    >>>>>>>>

Re: [Qemu-devel] Infinite IRQ injection when trying windows 10

[Dr. David Alan Gilbert]

* //-//ani  Nemati (hani.nemati@gmail.com) wrote:
> /usr/bin/qemu-system-x86_64 -name win10 -S -machine
> pc-i440fx-2.6,accel=kvm,usb=off -cpu Haswell -m 2048 -realtime mlock=off
> -smp 2,sockets=2,cores=1,threads=1 -uuid
> 9b3b910d-f3d1-494e-9471-943fc511d994 -no-user-config -nodefaults -chardev
> socket,id=charmonitor,path=/var/lib/libvirt/qemu/win10.monitor,server,nowait
> -mon chardev=charmonitor,id=monitor,mode=control -rtc
> base=localtime,driftfix=slew -global kvm-pit.lost_tick_policy=discard
> -no-hpet -no-shutdown -global PIIX4_PM.disable_s3=1 -global
> PIIX4_PM.disable_s4=1 -boot strict=on -device
> ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x5.0x7 -device
> ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x5
> -device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x5.0x1
> -device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x5.0x2
> -drive
> file=/home/hani/external1/win10.img,if=none,id=drive-ide0-0-0,format=qcow2
> -device
> ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1
> -netdev tap,fd=24,id=hostnet0 -device
> rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:6c:0a:a3,bus=pci.0,addr=0x3
> -chardev pty,id=charserial0 -device
> isa-serial,chardev=charserial0,id=serial0 -device usb-tablet,id=input0 -vnc
> 127.0.0.1:0 -device VGA,id=video0,vgamem_mb=16,bus=pci.0,addr=0x2 -device
> virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 -msg timestamp=on
> 
> Qemu version: 2.5
> Linux kernel: 4.2
> CPU: Interl i7-4790 CPU @3.60GHz
> Memory: Kingston DDR3-1600 MHz, 32G

Thanks; try replacing the driftfix=slew by driftfix=none and see if it helps.

Dave

> On Wed, Oct 19, 2016 at 2:59 PM, Dr. David Alan Gilbert <dgilbert@redhat.com
> > wrote:
> 
> > * //-//ani  Nemati (hani.nemati@gmail.com) wrote:
> > > Hi,
> > >
> > > Recently I was trying windows 10 on top of Qemu-KVM and I saw  4% of CPU
> > is
> > > being used all the time even when the windows VM is idle. I tested it for
> > > nested VM (Linux(L0)->Linux(L1)->windows(L2)) and I saw CPU usage
> > increased
> > > upto 45%. I traced my host and I saw there is an infinite interrupt loop
> > > which injected by qemu main process to my windows VM. I also traced the
> > > windows machine and I saw System process is handling that interrupt. The
> > > main qemu process injects IRQ 209 periodically. I wonder if it is a
> > > bug!!!!!
> >
> > What's the qemu commandline you're using and what version of qemu?
> > Also, what host hardware?
> >
> > Dave
> >
> > > Cheers,
> > > Hani
> > --
> > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> >
> 
> 
> 
> -- 
> <<<<<<<    /-/ /\ /\/ / /\/ *E* /\/\ /\ *T* /    >>>>>>>>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK