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From: Dave Hansen <dave.hansen@intel.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: alison.schofield@intel.com, Matthew Wilcox <willy@infradead.org>,
	Dan Williams <dan.j.williams@intel.com>,
	David Howells <dhowells@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	James Morris <jmorris@namei.org>, Ingo Molnar <mingo@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@alien8.de>,
	Peter Zijlstra <peterz@infradead.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	kai.huang@intel.com, Jun Nakajima <jun.nakajima@intel.com>,
	"Sakkinen, Jarkko" <jarkko.sakkinen@intel.com>,
	keyrings@vger.kernel.org,
	LSM List <linux-security-module@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>, X86 ML <x86@kernel.org>
Subject: Re: [RFC v2 00/13] Multi-Key Total Memory Encryption API (MKTME)
Date: Tue, 4 Dec 2018 12:32:54 -0800
Message-ID: <fa98a8d6-d592-0b49-c084-c20cca9a801f@intel.com> (raw)
In-Reply-To: <CALCETrXM_nQMFHsAfQGqqURL3=B46AXdiG+4p8Mpm6n4cOqXsw@mail.gmail.com>

On 12/4/18 12:00 PM, Andy Lutomirski wrote:
> On Tue, Dec 4, 2018 at 11:19 AM Andy Lutomirski <luto@kernel.org> wrote:
>> On Mon, Dec 3, 2018 at 11:37 PM Alison Schofield <alison.schofield@intel.com> wrote:
>> Finally, If you're going to teach the kernel how to have some user
>> pages that aren't in the direct map, you've essentially done XPO,
>> which is nifty but expensive.  And I think that doing this gets you
>> essentially all the benefit of MKTME for the non-pmem use case.  Why
>> exactly would any software want to use anything other than a
>> CPU-managed key for anything other than pmem?
> 
> Let me say this less abstractly.  Here's a somewhat concrete actual
> proposal.  Make a new memfd_create() flag like MEMFD_ISOLATED.  The
> semantics are that the underlying pages are made not-present in the
> direct map when they're allocated (which is hideously slow, but so be
> it), and that anything that tries to get_user_pages() the resulting
> pages fails.  And then make sure we have all the required APIs so that
> QEMU can still map this stuff into a VM.

I think we need get_user_pages().  We want direct I/O to work, *and* we
really want direct device assignment into VMs.

> And maybe we get fancy and encrypt this memory when it's swapped, but
> maybe we should just encrypt everything when it's swapped.

We decided long ago (and this should be in the patches somewhere) that
we wouldn't force memory to be encrypted in swap.  We would just
recommend it in the documentation as a best practice, especially when
using MKTME.

We can walk that back, of course, but that's what we're doing at the moment.

  reply index

Thread overview: 91+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-04  7:39 Alison Schofield
2018-12-04  7:39 ` [RFC v2 01/13] x86/mktme: Document the MKTME APIs Alison Schofield
2018-12-05 18:11   ` Andy Lutomirski
2018-12-05 19:22     ` Alison Schofield
2018-12-05 23:35       ` Andy Lutomirski
2018-12-06  8:04   ` Sakkinen, Jarkko
2018-12-04  7:39 ` [RFC v2 02/13] mm: Generalize the mprotect implementation to support extensions Alison Schofield
2018-12-06  8:08   ` Sakkinen, Jarkko
2018-12-04  7:39 ` [RFC v2 03/13] syscall/x86: Wire up a new system call for memory encryption keys Alison Schofield
2018-12-04  7:39 ` [RFC v2 04/13] x86/mm: Add helper functions for MKTME " Alison Schofield
2018-12-04  9:14   ` Peter Zijlstra
2018-12-05  5:49     ` Alison Schofield
2018-12-04 15:35   ` Andy Lutomirski
2018-12-05  5:52     ` Alison Schofield
2018-12-06  8:31   ` Sakkinen, Jarkko
2018-12-04  7:39 ` [RFC v2 05/13] x86/mm: Set KeyIDs in encrypted VMAs Alison Schofield
2018-12-06  8:37   ` Sakkinen, Jarkko
2018-12-04  7:39 ` [RFC v2 06/13] mm: Add the encrypt_mprotect() system call Alison Schofield
2018-12-06  8:38   ` Sakkinen, Jarkko
2018-12-04  7:39 ` [RFC v2 07/13] x86/mm: Add helpers for reference counting encrypted VMAs Alison Schofield
2018-12-04  8:58   ` Peter Zijlstra
2018-12-05  5:28     ` Alison Schofield
2018-12-04  7:39 ` [RFC v2 08/13] mm: Use reference counting for " Alison Schofield
2018-12-04  7:39 ` [RFC v2 09/13] mm: Restrict memory encryption to anonymous VMA's Alison Schofield
2018-12-04  9:10   ` Peter Zijlstra
2018-12-05  5:30     ` Alison Schofield
2018-12-05  9:07       ` Peter Zijlstra
2018-12-04  7:39 ` [RFC v2 10/13] keys/mktme: Add the MKTME Key Service type for memory encryption Alison Schofield
2018-12-06  8:51   ` Sakkinen, Jarkko
2018-12-06  8:54     ` Sakkinen, Jarkko
2018-12-06 15:11     ` Dave Hansen
2018-12-06 22:56       ` Sakkinen, Jarkko
2018-12-04  7:39 ` [RFC v2 11/13] keys/mktme: Program memory encryption keys on a system wide basis Alison Schofield
2018-12-04  9:21   ` Peter Zijlstra
2018-12-04  9:50     ` Kirill A. Shutemov
2018-12-05  5:44       ` Alison Schofield
2018-12-05  5:43     ` Alison Schofield
2018-12-05  9:10       ` Peter Zijlstra
2018-12-05 17:26         ` Alison Schofield
2018-12-04  7:39 ` [RFC v2 12/13] keys/mktme: Save MKTME data if kernel cmdline parameter allows Alison Schofield
2018-12-04  9:22   ` Peter Zijlstra
2018-12-07  2:14   ` Huang, Kai
2018-12-07  3:42     ` Alison Schofield
2018-12-07  6:39     ` Jarkko Sakkinen
2018-12-07  6:45       ` Jarkko Sakkinen
2018-12-07 11:47     ` Kirill A. Shutemov
2018-12-04  7:40 ` [RFC v2 13/13] keys/mktme: Support CPU Hotplug for MKTME keys Alison Schofield
2018-12-04  9:28   ` Peter Zijlstra
2018-12-05  5:32     ` Alison Schofield
2018-12-04  9:31   ` Peter Zijlstra
2018-12-05  5:36     ` Alison Schofield
2018-12-04  9:25 ` [RFC v2 00/13] Multi-Key Total Memory Encryption API (MKTME) Peter Zijlstra
2018-12-04  9:46   ` Kirill A. Shutemov
2018-12-05 20:32     ` Sakkinen, Jarkko
2018-12-06 11:22       ` Kirill A. Shutemov
2018-12-06 14:59         ` Dave Hansen
2018-12-07 10:12           ` Huang, Kai
2018-12-06 21:23         ` Sakkinen, Jarkko
2018-12-07 11:54           ` Kirill A. Shutemov
2018-12-04 19:19 ` Andy Lutomirski
2018-12-04 20:00   ` Andy Lutomirski
2018-12-04 20:32     ` Dave Hansen [this message]
2018-12-05 22:19   ` Sakkinen, Jarkko
2018-12-07  2:05     ` Huang, Kai
2018-12-07  6:48       ` Jarkko Sakkinen
2018-12-07 11:57     ` Kirill A. Shutemov
2018-12-07 21:59       ` Sakkinen, Jarkko
2018-12-07 23:45         ` Sakkinen, Jarkko
2018-12-07 23:48           ` Andy Lutomirski
2018-12-08  1:33           ` Huang, Kai
2018-12-08  3:53             ` Sakkinen, Jarkko
2018-12-12 15:31           ` Sakkinen, Jarkko
2018-12-12 16:29             ` Andy Lutomirski
2018-12-12 16:43               ` Sakkinen, Jarkko
2018-12-12 23:27                 ` Huang, Kai
2018-12-13  5:49                   ` Sakkinen, Jarkko
2018-12-13  5:52                     ` Sakkinen, Jarkko
2018-12-12 23:24               ` Huang, Kai
2018-12-07 23:35       ` Eric Rannaud
2018-12-05 23:49   ` Dave Hansen
2018-12-06  1:09     ` Andy Lutomirski
2018-12-06  1:25       ` Dan Williams
2018-12-06 15:39       ` Dave Hansen
2018-12-06 19:10         ` Andy Lutomirski
2018-12-06 19:31           ` Dave Hansen
2018-12-07  1:55       ` Huang, Kai
2018-12-07  4:23         ` Dave Hansen
2018-12-07 23:53         ` Andy Lutomirski
2018-12-08  1:11           ` Dave Hansen
2018-12-08  2:07           ` Huang, Kai
2018-12-05 20:30 ` Sakkinen, Jarkko

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