Re: KVM "fake DAX" flushing interface - discussion
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