[libvirt] QEMU -M nvdimm=on and hotplug

[Haozhong Zhang]

On 09/13/17 17:28 +0200, Michal Privoznik wrote:
> 
> BTW: I ran a migration from no nvdimm qemu to one that had -M nvdimm=on
> and guest migrated happily. So looks like guest ABI is stable (or at
> least stable enough not to crash). But since ACPI table is changed I
> doubt that.

One example that may cause trouble is that
1/ Guest OS got a pointer to an ACPI table A on the source host (w/o nvdimm=on)
2/ After migrating to the destination host (w/ nvdimm=on), the
   location of ACPI table A is occupied by NFIT. If guest OS tries to
   access ACPI table A via the pointer in step 1/, then it will access
   the wrong table.

> 
> Also, I found that hotunplug is not implemented yet?

So far there is no public specification defining NVDIMM hotunplug, so
we didn't implement it.


Haozhong


> 
> error: internal error: unable to execute QEMU command 'device_del':
> nvdimm device hot unplug is not supported yet.
> 
> Michal