Re: merge bouyer-xenpvh to HEAD

On Sat, 25 Apr 2020 at 14:15, Manuel Bouyer <[email protected]> wrote:
>
> On Sat, Apr 25, 2020 at 02:08:09PM +0100, Chavdar Ivanov wrote:
> > And so I did.
> >
> > Any pointers as to how to test it? My personal interest is in running
> > NetBSD guests under XCP-NG, at present they can run only in HVM mode.
> > One ofthe problems I have with this is that while the Realtek driver
> > performs as expected - it is 100mb/s one - the Intel driver is
> > actually almost slower, even if it is supposed to be 1000mb/s. I was
> > hoping I'd get decent enough network performance her with xennet - as
> > I am getting under FreeBSD GENERIC and the xn driver.
> >
> > (I have ran previously Xen with a NetBSD DOM0, but since qemu-nvmm
> > became available I switched to using it instead).
> >
> > Anyway, under FreeBSD 12 I get:
> >
> > Hyper-V Version: 0.0.0 [SP0]
> >   Features=0x870<APIC,HYPERCALL,VPINDEX,TMFREQ>
> >   PM Features=0x0 [C0]
> >   Features3=0x0
> > XEN: Hypervisor version 4.13 detected.
> > CPU: Intel(R) Xeon(R) CPU E31245 @ 3.30GHz (3292.62-MHz K8-class CPU)
> >   Origin="GenuineIntel"  Id=0x206a7  Family=0x6  Model=0x2a  Stepping=7
> >   ...
> > Hypervisor: Origin = "Microsoft Hv"
> >
> > and all the Xen devices get recognised; the machine is reported to be
> > running in PVHVM mode.
> >
> > Trying GENERIC_XENHVM, I get:
> >
> > Hyper-V Version: 0.0.0 [SP0]
> >   Features=0x870<APIC,HYPERCALL,VPINDEX,TMFREQ>
> >   PM Features=0 [C0]
> >   Features3=0
> >   Recommends: 00000000 00000000
> >   Limits: Vcpu:0 Lcpu:0 Int:0
> >   HW Features: 0000000b, AMD: 00000000
> > ...
> > Xen HVM domU (4.13)
> >
> > and none of the Xen devices get detected.
> >
> > $ sysctl -a | grep hyper
> > machdep.hypervisor = Hyper-V
> > machdep.hyperv.version = 0.0.0 [SP0]
> > machdep.hyperv.features = 0x870<APIC,HYPERCALL,VPINDEX,TMFREQ>
> > machdep.hyperv.pm_features = 0 [C0]
> > machdep.hyperv.features3 = 0
> >
> > and it basically works as usual GENERIC kernel.
>
> It seem that there is a mode in which Xen can emulate a Hyper-V hypervisor
> (ough). Can you disable it ?

I am not aware if this is possible at all; my point was that the
FreeBSD GENERIC kernel is able to see it as a Hyper-V platform and yet
configure all the xen devices, working in PVHVM mode.

>
> --
> Manuel Bouyer <[email protected]>
>      NetBSD: 26 ans d'experience feront toujours la difference
> --



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