Re: merge bouyer-xenpvh to HEAD

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

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 ?

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--