Re: [RFC PATCH 0/6] Support virtio-mem memory hotplug in TDX guests

[Kiryl Shutsemau <kas@kernel.org>]

On Thu, Jun 04, 2026 at 05:35:45AM -0400, Zhenzhong Duan wrote:
> 2. Re-accepting already-accepted memory returns errors. Ignoring these errors
> can mislead the guest into believing re-accepted memory is zeroed when it
> contains stale data.

Re-accepting concern is valid, but often overblown. Reaccepting memory
that never got allocated is fine.

> == About this series ==
> 
> This series takes a different direction, supporting start-private memory
> and addressing the limitations of previous series [1] by implementing a
> callback-based infrastructure that integrates TDX memory acceptance and
> release operations with proper subblock granularity.

You are presenting these callbacks as generic memory hotplug thingy, but
it is only plugged into virtio mem. ACPI hotplug won't accept/release
memory unless I miss something. Are you expecting them to cover non
virtio cases too?

And these callbacks feels like very ad-hoc solution.

> See Rick and Paolo's
> discussion about using TDG.MEM.PAGE.RELEASE in [1].

Having RELEASE in hotplug path without addressing private->shared
conversion first is odd. That's the most obvious path that has to be
covered first.

Hm?

> == Future work ==
> support lazy accept

It would be nice to have some outline on how we will get there to
understand if this patchset is stepping stone or dead end that has to be
thrown away later on.

Hot[un]plug is often used to manager overcommited host. Eager accept
might be counter-productive.


-- 
  Kiryl Shutsemau / Kirill A. Shutemov