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From: Andy Lutomirski <luto@amacapital.net>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-arch <linux-arch@vger.kernel.org>,
	"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
	"kvm list" <kvm@vger.kernel.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	"X86 ML" <x86@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	kasan-dev <kasan-dev@googlegroups.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	iommu@lists.linux-foundation.org,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Matt Fleming" <matt@codeblueprint.co.uk>,
	"Joerg Roedel" <joro@8bytes.org>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Andrey Ryabinin" <aryabinin@virtuozzo.com>,
	"Alexander Potapenko" <glider@google.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Dmitry Vyukov" <dvyukov@google.com>
Subject: Re: [RFC PATCH v1 00/18] x86: Secure Memory Encryption (AMD)
Date: Wed, 27 Apr 2016 07:39:24 -0700	[thread overview]
Message-ID: <CALCETrUdrMAmE6Vgj6_PALdmRZVVKa3QDwJtO=YDTOQdox=rhQ@mail.gmail.com> (raw)
In-Reply-To: <20160426225553.13567.19459.stgit@tlendack-t1.amdoffice.net>

On Tue, Apr 26, 2016 at 3:55 PM, Tom Lendacky <thomas.lendacky@amd.com> wrote:
> This RFC patch series provides support for AMD's new Secure Memory
> Encryption (SME) feature.
>
> SME can be used to mark individual pages of memory as encrypted through the
> page tables. A page of memory that is marked encrypted will be automatically
> decrypted when read from DRAM and will be automatically encrypted when
> written to DRAM. Details on SME can found in the links below.

Having read through the docs briefly, some questions:

1. How does the crypto work?  Is it straight AES-ECB?  Is it a
tweakable mode?  If so, what does into the tweak?  For example, if I
swap the ciphertext of two pages, does the plaintext of the pages get
swapped?  If not, why not?

2. In SEV mode, how does the hypervisor relocate a physical backing
page?  Does it simple move it and update the 2nd-level page tables?
If so, is the result of decryption guaranteed to be garbage if it
relocates a page and re-inserts it at the wrong guest physical
address?

3. In SEV mode, does anything prevent the hypervisor from resuming a
guest with the wrong ASID, or is this all relying on the resulting
corruption of the guest code and data to cause a crash?

4. As I understand it, the caches are all unencrypted, and they're
tagged with the physical address, *including* the SME bit (bit 47).
In SEV mode, are they also tagged with the ASID?  I.e. if I have a
page in cache for ASID 1 and I try to read it with ASID 2, will I get
a fresh copy decrypted with ASID 2's key?  If so, will the old ASID 1
copy be evicted, or will it stay in cache and be non-coherent?

--Andy

  parent reply	other threads:[~2016-04-27 14:40 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-26 22:55 [RFC PATCH v1 00/18] x86: Secure Memory Encryption (AMD) Tom Lendacky
2016-03-22 13:00 ` Pavel Machek
2016-04-27 14:05   ` Borislav Petkov
2016-04-27 14:30     ` Pavel Machek
2016-04-27 14:39       ` Borislav Petkov
2016-04-27 14:58         ` Pavel Machek
2016-04-27 15:47         ` Pavel Machek
2016-04-27 14:21   ` Tom Lendacky
2016-04-26 22:56 ` [RFC PATCH v1 01/18] x86: Set the write-protect cache mode for AMD processors Tom Lendacky
2016-04-27 14:33   ` Andy Lutomirski
2016-04-27 14:44     ` Tom Lendacky
2016-04-27 14:47       ` Andy Lutomirski
2016-04-27 15:05         ` Tom Lendacky
2016-04-27 15:12           ` Andy Lutomirski
2016-04-27 15:31             ` Borislav Petkov
2016-04-27 15:34               ` Andy Lutomirski
2016-04-26 22:56 ` [RFC PATCH v1 02/18] x86: Secure Memory Encryption (SME) build enablement Tom Lendacky
2016-03-22 13:01   ` Pavel Machek
2016-04-27 15:17     ` Tom Lendacky
2016-04-27 15:30       ` Pavel Machek
2016-04-27 15:41         ` Borislav Petkov
2016-04-27 16:41           ` Pavel Machek
2016-04-27 17:07             ` Robin Murphy
2016-04-27 17:12             ` Borislav Petkov
2016-04-26 22:56 ` [RFC PATCH v1 03/18] x86: Secure Memory Encryption (SME) support Tom Lendacky
2016-03-22 13:03   ` Pavel Machek
2016-04-27 16:20     ` Tom Lendacky
2016-04-26 22:56 ` [RFC PATCH v1 04/18] x86: Add the Secure Memory Encryption cpu feature Tom Lendacky
2016-04-26 22:56 ` [RFC PATCH v1 05/18] x86: Handle reduction in physical address size with SME Tom Lendacky
2016-04-26 22:56 ` [RFC PATCH v1 06/18] x86: Provide general kernel support for memory encryption Tom Lendacky
2016-04-26 22:57 ` [RFC PATCH v1 07/18] x86: Extend the early_memmap support with additional attrs Tom Lendacky
2016-04-26 22:57 ` [RFC PATCH v1 08/18] x86: Add support for early encryption/decryption of memory Tom Lendacky
2016-04-26 22:57 ` [RFC PATCH v1 09/18] x86: Insure that memory areas are encrypted when possible Tom Lendacky
2016-04-26 22:57 ` [RFC PATCH v1 10/18] x86/efi: Access EFI related tables in the clear Tom Lendacky
2016-05-10 13:43   ` Matt Fleming
2016-05-10 13:57     ` Borislav Petkov
2016-05-12 18:20       ` Tom Lendacky
2016-05-24 14:54         ` Tom Lendacky
2016-05-25 16:09           ` Daniel Kiper
2016-05-25 19:30           ` Matt Fleming
2016-05-26 13:45             ` Tom Lendacky
2016-06-08 10:07               ` Matt Fleming
2016-06-09 16:16                 ` Tom Lendacky
2016-06-13 12:03                   ` Matt Fleming
2016-06-13 12:34                     ` Matt Fleming
2016-06-13 15:16                     ` Tom Lendacky
2016-06-08 11:18   ` Matt Fleming
2016-06-09 18:33     ` Tom Lendacky
2016-06-13 13:51       ` Matt Fleming
2016-06-15 13:17         ` Tom Lendacky
2016-06-16 14:38           ` Tom Lendacky
2016-06-17 15:51             ` Matt Fleming
2016-04-26 22:57 ` [RFC PATCH v1 11/18] x86: Decrypt trampoline area if memory encryption is active Tom Lendacky
2016-04-26 22:58 ` [RFC PATCH v1 12/18] x86: Access device tree in the clear Tom Lendacky
2016-04-26 22:58 ` [RFC PATCH v1 13/18] x86: DMA support for memory encryption Tom Lendacky
     [not found]   ` <20160429071743.GC11592@char.us.oracle.com>
2016-04-29 15:12     ` Tom Lendacky
     [not found]       ` <20160429162757.GA1191@char.us.oracle.com>
2016-04-29 23:49         ` Tom Lendacky
2016-04-26 22:58 ` [RFC PATCH v1 14/18] iommu/amd: AMD IOMMU " Tom Lendacky
2016-04-26 22:58 ` [RFC PATCH v1 15/18] x86: Enable memory encryption on the APs Tom Lendacky
2016-05-01 22:10   ` Huang, Kai
2016-05-03 15:59     ` Tom Lendacky
2016-04-26 22:58 ` [RFC PATCH v1 16/18] x86: Do not specify encrypted memory for VGA mapping Tom Lendacky
2016-04-26 22:58 ` [RFC PATCH v1 17/18] x86/kvm: Enable Secure Memory Encryption of nested page tables Tom Lendacky
2016-04-26 22:59 ` [RFC PATCH v1 18/18] x86: Add support to turn on Secure Memory Encryption Tom Lendacky
2016-03-22 13:13   ` Pavel Machek
2016-04-27 14:39 ` Andy Lutomirski [this message]
2016-04-27 20:10   ` [RFC PATCH v1 00/18] x86: Secure Memory Encryption (AMD) Tom Lendacky
2016-05-02 18:31     ` Andy Lutomirski
2016-05-09 15:13       ` Paolo Bonzini
2016-05-09 21:08         ` Tom Lendacky
2016-05-10 11:23           ` Paolo Bonzini
2016-05-10 12:04             ` Borislav Petkov
2016-04-30  6:13 ` Elliott, Robert (Persistent Memory)
2016-05-03 15:55   ` Tom Lendacky
  -- strict thread matches above, loose matches on Subject: below --
2016-04-26 22:45 Tom Lendacky

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