Re: hyper-v support in KVM

[Vadim Rozenfeld <vrozenfe@redhat.com>]

On Mon, 2014-02-24 at 03:01 +0000, Zhang, Yang Z wrote:
> Vadim Rozenfeld wrote on 2014-02-14:
> > On Fri, 2014-02-14 at 02:35 +0000, Liu, RongrongX wrote:
> >> Vadim Rozenfeld wrote on 2014-02-12:
> >>> On Wed, 2014-02-12 at 01:33 +0000, Zhang, Yang Z wrote:
> >>>> Vadim Rozenfeld wrote on 2014-02-10:
> >>>>> On Mon, 2014-02-10 at 08:21 +0000, Zhang, Yang Z wrote:
> >>>>>> Hi Vadim,
> >>>>>> 
> >>>>>> Do you know the latest status of Hyper-v Enlightenments
> >>>>>> supporting in
> >>> KVM?
> >>>>> Like how many Hyper-v interfaces are supported in KVM?
> >>>>> 
> >>>>> Hi Yang,
> >>>>> 
> >>>>> There is no many at the moment. KVM currently supports the
> >>>>> following Hyper-V features:
> >>>>> 
> >>>>> Guest Spinlocks
> >>>>> http://msdn.microsoft.com/en-us/library/windows/hardware/ff539
> >>>>> 08
> >>>>> 1%
> >>>>> 28v=vs.85%29.aspx
> >>>>> 
> >>>>> Local APIC MSR Accesses
> >>>>> http://msdn.microsoft.com/en-us/library/windows/hardware/ff542
> >>>>> 39
> >>>>> 6%
> >>>>> 28v=vs.85%29.aspx
> >>>>> 
> >>>>> Reference Time Counter
> >>>>> http://msdn.microsoft.com/en-us/library/windows/hardware/ff542
> >>>>> 63
> >>>>> 7%
> >>>>> 28v=vs.85%29.aspx
> >>>>> 
> >>>>> We are going to add: Reference TSC Page
> >>>>> http://msdn.microsoft.com/en-us/library/windows/hardware/ff542
> >>>>> 64
> >>>>> 3%
> >>>>> 28v=vs.85%29.aspx
> >>>>> 
> >>>>> Lazy EOI support, maybe more.
> >>>>> 
> >>>> 
> >>>> Thanks for your update. More questions: I want to measure the
> >>>> performance improvement with hyper-v features enabled. So I want to
> >>>> know: Are those features enabled by default in KVM?
> >>> In KVM - yes, but you also need to specify them in QEMU command line.
> >>> They can be enabled by -cpu features hv_vapic, hv_spinlocks,
> >>> hv_time, and hv_relaxed
> >> Hi Vadim,
> >> in QEMU command line, how to enable these feature?
> >> I try it with
> >> 1. [root@vt-snb9 ]#qemu-system-x86_64 -enable-kvm -m 2048 -smp 2
> >> -net none win8.1.img -cpu feature
> >> hv_vapic,+hv_spinlocks,+hv_time,+hv_relaxed
> >>  qemu-system-x86_64: -cpu feature: drive with bus=0, unit=0
> >> (index=0) exists 2. [root@vt-snb9]# qemu-system-x86_64 -enable-kvm
> >> -m 2048 -smp
> >> 2 -net none win8.1.img -cpu
> >> qemu64,+hv_vapic,+hv_spinlocks,+hv_time,+hv_relaxed
> > 
> > something like this: -cpu qemu64,
> > +x2apic,family=0xf,hv_vapic,hv_spinlocks=0xfff,hv_relaxed,hv_time
> > 
> > (for hv_vapic we also need x2apic to be enabled)
> 
> I saw the win8.1 guest boot up fail with error code 0x0000005c after enabling hv_vapic on my ivy bridge-EP box. But it works well on my Sandy bridge-EP. Any thought?
> 
What are the bug check parameters coming with HAL_INITIALIZATION_FAILED
bug check? Is your guest 32 or 64-bit? How does it work with Win8?

Thanks,
Vadim.

> 
> > 
> > Best regards,
> > Vadim.
> > 
> >> CPU feature hv_vapic not found
> >> CPU feature hv_spinlocks not found
> >> CPU feature hv_time not found
> >> CPU feature hv_relaxed not found
> >> CPU feature hv_vapic not found
> >> CPU feature hv_spinlocks not found
> >> CPU feature hv_time not found
> >> CPU feature hv_relaxed not found
> >> VNC server running on `::1:5900'
> >> 
> >> 
> >>>> How to turn off/on it manually?
> >>> Yes. From the QEMU command line.
> >>> 
> >>>> And how can I know whether guest is using it really?
> >>> There are two options - printk from the KVM side or WinDbg from
> >>> the guest side. But in case of hv_time you can check the value
> >>> returned by QueryPerformanceFrequency
> >>> http://msdn.microsoft.com/en-us/library/windows/desktop/ms644905%
> >>> 28v=vs.85%29.aspx
> >>> it should be 10MHz
> >>> 
> >>>>  Also, Do you have any performance data?
> >>> http://www.linux-kvm.org/wiki/images/0/0a/2012-forum-kvm_hyperv.pd
> >>> f
> >>> pp 16, 18
> >>> I compared DPC and ISR times with xperf for two cases - with and
> >>> without enlightenment.
> >>> I also have seen reports mentioned around 5-10 percent CPU usage
> >>> drop on the host side, when loading guest with some disk-stress tests.
> >>> 
> >>>> 
> >>>>> Kind regards.
> >>>>> Vadim.
> >>>>> 
> >>>>>> 
> >>>>>> best regards
> >>>>>> yang
> >>>>>> 
> >>>>>> --
> >>>>>> To unsubscribe from this list: send the line "unsubscribe kvm"
> >>>>>> in the body of a message to majordomo@vger.kernel.org More
> >>>>>> majordomo info at  http://vger.kernel.org/majordomo-info.html
> >>>>> 
> >>>>> 
> >>>> 
> >>>> 
> >>>> Best regards,
> >>>> Yang
> >>>> 
> >>>> 
> >>> 
> >> 
> >
> 
> 
> Best regards,
> Yang
> 
>