From: qi.fuli(a)fujitsu.com <qi.fuli(a)fujitsu.com>
Sent: Sunday, February 24, 2019 8:48 PM
To: Dexuan Cui <decui(a)microsoft.com>; Dave Jiang <dave.jiang(a)intel.com>;
Vishal Verma <vishal.l.verma(a)intel.com>; Dan Williams
<dan.j.williams(a)intel.com>; linux-nvdimm(a)lists.01.org; Michael Kelley
<mikelley(a)microsoft.com>; Johannes Thumshirn <jthumshirn(a)suse.de>
Subject: RE: [ndctl PATCH v2 4/4] ndctl, monitor: support
> Hi Qi,
> Generally speaking, I agree with you, but here the fact is that we can only
> one single event "dimm-health-state" for Hyper-V Virtual NVDIMM, and the
> events are meaningless for Hyper-V Virtual NVDIMM, as they're not
> Hyper-V Virtual NVDIMM.
> So, if the user specifies more events than just "dimm-health-state", or
> specify "dimm-health-state", it's reasonable to force
> ND_EVENT_HEALTH_STATE, and I explicitly print a warning.
> The line "monitor.event_flags = ND_EVENT_HEALTH_STATE" only runs in a
> running on Hyper-V. It can't adversely affect bare metal cases. In a Linux VM
> Hyper-V, all the NVDIMMs appearing in the VM are Hyper-V Virtual
> A physical NVDIMM can't be directly passed through to a VM and the
> Xen, KVM, Hyper-V, Qemu, etc.) have to virtualize it to make it available to a
VM. In a
> VM, the NVDIMM_FAMILY is NVDIMM_FAMILY_HYPERV only when the VM
> So I think we should be good. :-)
> -- Dexuan
Thanks for your explanation.
I think at least we should document it into man page, so that the users could
know that their options may be modified by monitor.
Good suggestion! After the patch receives more comments and/or after it's
accepted, I'll add a new patch for the man page:
Though I have a little concern about that there may be other events
Hyper-V Virtual NVDIMM can be monitored in future...
As far as I know, that's unlikely, at least in the foreseeable future. :-)
The VM is supposed to see a virtual NVDIMM, for which the hypervisor only
emulates the minimal necessary info, based on the physical NVDIMM's state.