Re: [RFC RFT PATCH 1/4] hv: Leak pages if set_memory_encrypted() fails

Edgecombe, Rick P
2024-03-01T20:47:17Z

On Fri, 2024-03-01 at 20:21 +0000, Michael Kelley wrote:
>
> The Hyper-V case can actually be a third path when a paravisor
> is being used.  In that case, for both TDX and SEV-SNP, the
> hypervisor callbacks in __set_memory_enc_pgtable() go
> to Hyper-V specific functions that talk to the paravisor. Those
> callbacks never panic. After a failure, either at the paravisor
> level or in the paravisor talking to the hypervisor/VMM, the
> decrypted/encrypted state of the memory isn't known.  So
> leaking the memory is still the right thing to do, and your
> patch set is good. But in the Hyper-V with paravisor case,
> the leaking is applicable more broadly than just TDX.
>
> The text in the commit message isn't something that I'll
> go to the mat over.  But I wanted to offer the slightly broader
> perspective.

Oh, interesting. I think I missed it because it only has a special
enc_status_change_finish(). But yea. It does sound like the text you
suggested is more accurate. I'll update it.