Messages in this thread | | | Date | Wed, 2 Nov 2022 16:26:56 -0500 | From | Michael Roth <> | Subject | Re: [PATCH v9 1/8] mm: Introduce memfd_restricted system call to create restricted user memory |
| |
On Thu, Nov 03, 2022 at 12:14:04AM +0300, Kirill A. Shutemov wrote: > On Mon, Oct 31, 2022 at 12:47:38PM -0500, Michael Roth wrote: > > > > In v8 there was some discussion about potentially passing the page/folio > > and order as part of the invalidation callback, I ended up needing > > something similar for SEV-SNP, and think it might make sense for other > > platforms. This main reasoning is: > > > > 1) restoring kernel directmap: > > > > Currently SNP (and I believe TDX) need to either split or remove kernel > > direct mappings for restricted PFNs, since there is no guarantee that > > other PFNs within a 2MB range won't be used for non-restricted > > (which will cause an RMP #PF in the case of SNP since the 2MB > > mapping overlaps with guest-owned pages) > > That's news to me. Where the restriction for SNP comes from? There's no > such limitation on TDX side AFAIK? > > Could you point me to relevant documentation if there's any?
I could be mistaken, I haven't looked into the specific documentation and was going off of this discussion from a ways back:
https://lore.kernel.org/all/YWb8WG6Ravbs1nbx@google.com/
Sean, is my read of that correct? Do you happen to know where there's some documentation on that for the TDX side?
Thanks,
Mike
> > -- > Kiryl Shutsemau / Kirill A. Shutemov
| |