Hey Paolo, I agree that in the future it would be great if the Windows Hypervisor Platform supported that and if that happens there is no reason to differentiate the two.
However, today WHPX actually doesn’t support any of the synthetic enlightenments that Hyper-V does. We are really trying to make the Windows Hypervisor Platform a generic hypervisor where as Hyper-V is a specific implementation on top of that hypervisor (and QEMU is another such implementation). For example, VMBus was mentioned but as it stands today, VMBus is not supported in WHPX due to lack of support for hypercalls. Additionally, timer enlightenments that you mentioned would not be supported through synthetic paths and instead run emulated as devices (hpet etc.). I hope this adds some clarity here for why WHPX doesn’t implement hyperv-proto.h as Hyper-V != Windows Hypervisor Platform in many aspects. Please let me know if there is anything else I can explain to help clarify the two. Thanks, Justin > -----Original Message----- > From: Paolo Bonzini <pbonz...@redhat.com> > Sent: Wednesday, May 16, 2018 12:35 AM > To: apilotti <apilo...@cloudbasesolutions.com> > Cc: petrutlucia...@gmail.com; Lucian Petrut > <lpet...@cloudbasesolutions.com>; Eduardo Habkost > <ehabk...@redhat.com>; open list:All patches CC here <qemu- > de...@nongnu.org>; Justin Terry (VM) <jute...@microsoft.com>; Richard > Henderson <r...@twiddle.net> > Subject: Re: [Qemu-devel] [PATCH] WHPX Add signature CPUID > > On 16/05/2018 01:55, Alessandro Pilotti wrote: > > Hi Paolo, > > > > The main reason for different signatures is to allow guest workloads > > to be aware of the differences between the two platforms (eg VirtIO vs > > VMBus). > > Why does it matter? CPUID tells you about the enlightenments that the > hypervisor provides, not the availability of the VMBus. > > VMBus requires some of the enlightenments, mostly related to the synthetic > interrupt controllers, but the opposite is not true---you can have > enlightenments without VMBus, and in fact you probably want WHPX to > enable the relaxed timing enlightenment. > > Thanks, > > Paolo
