> From: qi.f...@fujitsu.com <qi.f...@fujitsu.com>
> Sent: Thursday, February 21, 2019 12:40 AM
> > ...
> > + /*
> > + * Hyper-V Virtual NVDIMM doesn't use ND_CMD_SMART to get the
> > health info. Instead, it uses ND_CMD_CALL, so the checking here can't
> > + * apply, and it doesn't support threshold alarms -- actually it only
> > + * supports one event: ND_EVENT_HEALTH_STATE.
> > + */
> > + if (ndctl_dimm_get_cmd_family(dimm) == NVDIMM_FAMILY_HYPERV) {
> > + if (monitor.event_flags != ND_EVENT_HEALTH_STATE) {
> > + monitor.event_flags = ND_EVENT_HEALTH_STATE;
> > +
> > + notice(&monitor, "%s: only dimm-health-state can be
> > monitored\n", name);
> Hi Dexuan,
> I think that "monitor" should be a "read-only" command and can't force the
> users to change their options.
> The monitor.event_flags will work for all NVDIMMs to be monitored.
> I don't know whether a physical NVDIMM could be mounted on the OS
> running inside of a virtual machine.
> If yes, this forced changing may cause an exception of monitoring smart
> threshold events on NVDIMM.
>
> Thanks,
> Qi
Hi Qi,
Generally speaking, I agree with you, but here the fact is that we can only
monitor this one single event "dimm-health-state" for Hyper-V Virtual NVDIMM,
and the other events are meaningless for Hyper-V Virtual NVDIMM, as they're
not supported by Hyper-V Virtual NVDIMM.
So, if the user specifies more events than just "dimm-health-state", or the user
doesn't specify "dimm-health-state", it's reasonable to force
monitor.event_flags
to equal to ND_EVENT_HEALTH_STATE, and I explicitly print a warning.
The line "monitor.event_flags = ND_EVENT_HEALTH_STATE" only runs in a Linux
VM running on Hyper-V. It can't adversely affect bare metal cases. In a Linux
VM on Hyper-V, all the NVDIMMs appearing in the VM are Hyper-V Virtual NVDIMMs.
A physical NVDIMM can't be directly passed through to a VM and the hypervisors
(e.g., 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 runs on Hyper-V.
So I think we should be good. :-)
Thanks,
-- Dexuan
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