[libvirt-users] SEV machines and memory pinning
Hello,
I am working on implementing SEV support in OpenStack. There are some
questions that came up in the discussion of the spec [0]
[0] https://review.openstack.org/#/c/641994/
As far as i understand, the memory for SEV machines need to be pinned so
that it doesn't migrate to swap and page migration. ROMS, UEFI pflash
and video RAM should be pinned too.
Initially we planned to use hard_limit of <memtune> element to pin the
memory. However, from the discussion in the spec it seems that there is
no way to determine a good enough value and that hard_limit should not
be used at all.
What should be used then?
There is a suggestion to use something like this:
<memoryBacking>
<hugepages>
<page size="2" unit="M" nodeset="1"/>
</hugepages>
<nosharepages/>
<locked/>
<source type="file"/>
<access mode="shared"/>
<allocation mode="immediate"/>
</memoryBacking>
Will it work? Are there any caveats we should remember about with this
config? If we can use it, is there anything that would be redundant or
not necessary for our case?