Re: [Xen-devel] [RFC XEN PATCH v2 00/15] Add vNVDIMM support to HVM domains

[Dan Williams <dan.j.williams@xxxxxxxxx>]

>> I don't think KVM has the same issue, but honestly I don't have the
>> full mental model of how KVM supports mmap. I've at least been able to
>> run a guest where the "pmem" is just dynamic page cache on the host
>> side so the physical memory mapping is changing all the time due to
>> swap. KVM does not have this third-party M2P mapping table to keep up
>> to date so I assume it is just handled by the standard mmap support
>> for establishing a guest physical address range and the standard
>> mapping-invalidate + remap mechanism just works.
>
> Could it be possible to have an Xen driver that would listen on
> these notifications and percolate those changes this driver. Then
> this driver would make the appropiate hypercalls to update the M2P ?
>
> That would solve the 2/ I think?

I think that could work. That sounds like userfaultfd support for DAX
which is something I want to take a look at in the next couple kernel
cycles for other reasons like live migration of guest-VMs with DAX
mappings.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel