Messages in this thread | | | Date | Sat, 15 Jun 2019 01:43:09 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH, RFC 18/62] x86/mm: Implement syncing per-KeyID direct mappings |
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On Fri, Jun 14, 2019 at 11:51:32AM +0200, Peter Zijlstra wrote: > On Wed, May 08, 2019 at 05:43:38PM +0300, Kirill A. Shutemov wrote: > > For MKTME we use per-KeyID direct mappings. This allows kernel to have > > access to encrypted memory. > > > > sync_direct_mapping() sync per-KeyID direct mappings with a canonical > > one -- KeyID-0. > > > > The function tracks changes in the canonical mapping: > > - creating or removing chunks of the translation tree; > > - changes in mapping flags (i.e. protection bits); > > - splitting huge page mapping into a page table; > > - replacing page table with a huge page mapping; > > > > The function need to be called on every change to the direct mapping: > > hotplug, hotremove, changes in permissions bits, etc. > > And yet I don't see anything in pageattr.c.
You're right. I've hooked up the sync in the wrong place. > > Also, this seems like an expensive scheme; if you know where the changes > where, a more fine-grained update would be faster.
Do we have any hot enough pageattr users that makes it crucial?
I'll look into this anyway.
-- Kirill A. Shutemov
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