Hi, On Fri, Mar 8, 2024 at 9:05 PM Manwaring, Derek <derekmn@xxxxxxxxxx> wrote: > > On 2024-03-08 at 10:46-0700, David Woodhouse wrote: > > On Fri, 2024-03-08 at 09:35 -0800, David Matlack wrote: > > > I think what James is looking for (and what we are also interested > > > in), is _eliminating_ the ability to access guest memory from the > > > direct map entirely. And in general, eliminate the ability to access > > > guest memory in as many ways as possible. > > > > Well, pKVM does that... > > Yes we've been looking at pKVM and it accomplishes a lot of what we're trying > to do. Our initial inclination is that we want to stick with VHE for the lower > overhead. We also want flexibility across server parts, so we would need to > get pKVM working on Intel & AMD if we went this route. > > Certainly there are advantages of pKVM on the perf side like the in-place > memory sharing rather than copying as well as on the security side by simply > reducing the TCB. I'd be interested to hear others' thoughts on pKVM vs > memfd_secret or general ASI. The work we've done for pKVM is still an RFC [*], but there is nothing in it that limits it to nVHE (at least not intentionally). It should work with VHE and hVHE as well. On respinning the patch series [*], we plan on adding support for normal VMs to use guest_memfd() as well in arm64, mainly for testing, and to make it easier for others to base their work on it. Cheers, /fuad [*] https://lore.kernel.org/all/20240222161047.402609-1-tabba@xxxxxxxxxx > > Derek >
