svn commit: r297699 - head/sys/dev/hyperv/vmbus

[Sepherosa Ziehau]

On Fri, Apr 8, 2016 at 10:50 PM, John Baldwin <jhb at freebsd.org> wrote:
> On Friday, April 08, 2016 09:20:47 AM Sepherosa Ziehau wrote:
>> Author: sephe
>> Date: Fri Apr  8 09:20:46 2016
>> New Revision: 297699
>> URL: https://svnweb.freebsd.org/changeset/base/297699
>>
>> Log:
>>   hyperv: Revert r297481
>>
>>   Use vm_guest == VM_GUEST_HV is not enough to determine whether FreeBSD
>>   is running on Hyper-V or not.  What a mess.
>>
>>   Reported by:        smokehydration tutanota com
>>   Sponsored by:       Microsoft OSTC
>
> Ewww, does this mean Hyper-V doesn't always report itself via the VM
> CPUID leafs?  (Or is it not setting the HV cpuid feature bit?)

Some other hypervisors reuse Hyper-V's ID.  So relying on the
ID==Hyper-V is not going to work.  We have a patch to do more cpuids
to detect the existence of the Hyper-V time counter and other bits
(event timer, etc), which do not hooked to the vmbus.

Thanks,
sephe

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