Re: [Qemu-devel] KVM "fake DAX" flushing interface - discussion

[Pankaj Gupta]

Hello Dan,

> Not a flag, but a new "Address Range Type GUID". See section "5.2.25.2
> System Physical Address (SPA) Range Structure" in the ACPI 6.2A
> specification. Since it is a GUID we could define a Linux specific
> type for this case, but spec changes would allow non-Linux hypervisors
> to advertise a standard interface to guests.
> 

I have added new SPA with a GUUID for this memory type and I could add 
this new memory type in System memory map. I need help with the namespace
handling for this new type As mentioned in [1] discussion:

- Create a new namespace for this new memory type
- Teach libnvdimm how to handle this new namespace 

I have some queries on this:

1] How namespace handling of this new memory type would be?
  
2] There are existing namespace types: 
  ND_DEVICE_NAMESPACE_IO, ND_DEVICE_NAMESPACE_PMEM, ND_DEVICE_NAMESPACE_BLK

  How libnvdimm will handle this new name-space type in conjuction with existing
  memory type, region & namespaces?  

3] For sending guest to host flush commands we still have to think about some 
   async way?
    
[1] https://lists.gnu.org/archive/html/qemu-devel/2017-07/msg08404.html 

Thanks,
Pankaj