Re: [Qemu-devel] [Help] Windows2012 as Guest 64+cores on KVM Halts

[Gonglei (Arei)]

Hi,

> Behalf Of Yan Vugenfirer
> 
> Hi,
> 
> First off all to use more than 64 CPUs on Windows you should use CPU grouping.
> Each group can contain maximum 64 CPUs. Here is a good article explaining
> possible configurations:
> https://msdn.microsoft.com/en-us/windows/hardware/drivers/devtest/boot-p
> arameters-to-test-drivers-for-multiple-processor-group-support
> <https://msdn.microsoft.com/en-us/windows/hardware/drivers/devtest/boot-
> parameters-to-test-drivers-for-multiple-processor-group-support> and another
> one on the grouping subject:
> https://blogs.technet.microsoft.com/mlucas/2012/03/15/windows-server-and-
> processor-cores/
> <https://blogs.technet.microsoft.com/mlucas/2012/03/15/windows-server-an
> d-processor-cores/>
> 
> Regarding the boot failure - it is quite possible that Windows cannot handle
> more that 64 logical CPUs on one physical CPU.
> 

Thanks for your reply. :)

But We tested the same cases on Xen platform and VMware, and
the guest booted successfully.

Today I also tested on tcg, the guest also boots successfully.

BTW, if we disable hyper-v, there isn't problem on boot for the case.

QEMU command line (enable hyper-v with hv_relaxed):

# ./qemu-system-x86_64 -name win2012 -machine accel=kvm,usb=off -cpu 
qemu64,hv_relaxed -m 4001 -realtime mlock=off -smp 
68,sockets=1,cores=68,threads=1 \
-drive file=/mnt/sdb/gonglei/win2012_r2_dc_64_raw,if=none,id=drive-ide0-0-0 
-device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 \
-boot menu=on -device piix3-usb-uhci,id=uhci -chardev 
file,id=seabios,path=/home/seabios.log -device 
isa-debugcon,iobase=0x402,chardev=seabios \
-monitor stdio -device cirrus-vga,id=video0,vgamem_mb=16 -vnc 0.0.0.0:10

So, I think it's possible a KVM bug on Hyper-V enlightenments support. 

Any help will be appreciated!

CC'ing Paolo, Radim and Vadim.

Thanks,
-Gonglei

> Best regards,
> Yan.
> > On 9 Feb 2017, at 08:18, hangaohuai <address@hidden> wrote:
> >
> > Dear all:
> > I try to boot windows2012R2 (more than 64 cores)on kvm platform with
> hyper-v on*<relaxed state='on'/>*.
> > the guest halts on the starting time.
> > Also tested in these cases:
> > <topology sockets='64' cores='1' threads='1'/>  - boot sucess
> > <topology sockets='1' cores='64' threads='1'/>  - boot sucess
> > <topology sockets='1' cores='1' threads='64'/>  - boot sucess
> > <topology sockets='1' cores='68' threads='1'/>  - boot failed
> > <topology sockets='68' cores='1' threads='1'/>  - boot sucess(in Guest we
> can found 64)
> > <topology sockets='1' cores='1' threads='68'/>  - boot failed
> >
> > Environment:
> > GUEST:
> >  windows2012R2
> > HOST:
> >    kernel version:4.10.0-rc4
> >    QEMU version:QEMU emulator version 2.8.50
> (v2.8.0-664-gd1c82f7-dirty)
> > part of GuestXML:
> >  <vcpu placement='static'>68</vcpu>
> >  <resource>
> >    <partition>/machine</partition>
> >  </resource>
> >  <os>
> >    <type arch='x86_64' machine='pc-i440fx-2.3'>hvm</type>
> >    <boot dev='hd'/>
> >  </os>
> >  <features>
> >    <acpi/>
> >    <apic/>
> >    <pae/>
> >    <hyperv>
> >      <relaxed state='on'/>
> >    </hyperv>
> >  </features>
> >  <cpu>
> >    <topology sockets='1' cores='68' threads='1'/>
> >  </cpu>
> >
> > //////////////////////////////////
> > debug info:
> > virsh qemu-monitor-command win2012 --hmp "info cpus"
> >  CPU #61: pc=0xfffff8031296a21c thread_id=21410
> >  CPU #62: pc=0xfffff8031296a21c thread_id=21411
> >  CPU #63: pc=0xfffff8031296a21c thread_id=21414
> >  CPU #64: pc=0x00000000000fd31c (halted) thread_id=21415
> >  CPU #65: pc=0x00000000000fd31c (halted) thread_id=21416
> >  CPU #66: pc=0x00000000000fd31c (halted) thread_id=21417
> >  CPU #67: pc=0x00000000000fd31c (halted) thread_id=21418
> >
> >
> > Any suggestions?
> >
> > Thanks a lot.
> >
> > Gaohuai Han
> >
> >