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From: Matt Fleming <matt@codeblueprint.co.uk>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-arch@vger.kernel.org, linux-efi@vger.kernel.org,
	kvm@vger.kernel.org, linux-doc@vger.kernel.org, x86@kernel.org,
	linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
	linux-mm@kvack.org, iommu@lists.linux-foundation.org,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"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 10/18] x86/efi: Access EFI related tables in the clear
Date: Tue, 10 May 2016 14:43:58 +0100	[thread overview]
Message-ID: <20160510134358.GR2839@codeblueprint.co.uk> (raw)
In-Reply-To: <20160426225740.13567.85438.stgit@tlendack-t1.amdoffice.net>

On Tue, 26 Apr, at 05:57:40PM, Tom Lendacky wrote:
> The EFI tables are not encrypted and need to be accessed as such. Be sure
> to memmap them without the encryption attribute set. For EFI support that
> lives outside of the arch/x86 tree, create a routine that uses the __weak
> attribute so that it can be overridden by an architecture specific routine.
> 
> When freeing boot services related memory, since it has been mapped as
> un-encrypted, be sure to change the mapping to encrypted for future use.
> 
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
>  arch/x86/include/asm/cacheflush.h  |    3 +
>  arch/x86/include/asm/mem_encrypt.h |   22 +++++++++++
>  arch/x86/kernel/setup.c            |    6 +--
>  arch/x86/mm/mem_encrypt.c          |   56 +++++++++++++++++++++++++++
>  arch/x86/mm/pageattr.c             |   75 ++++++++++++++++++++++++++++++++++++
>  arch/x86/platform/efi/efi.c        |   26 +++++++-----
>  arch/x86/platform/efi/efi_64.c     |    9 +++-
>  arch/x86/platform/efi/quirks.c     |   12 +++++-
>  drivers/firmware/efi/efi.c         |   18 +++++++--
>  drivers/firmware/efi/esrt.c        |   12 +++---
>  include/linux/efi.h                |    3 +
>  11 files changed, 212 insertions(+), 30 deletions(-)

The size of this change is completely unexpected. Why is there so much
churn to workaround this new feature?

Is it not possible to maintain some kind of kernel virtual address
mapping so memremap*() and friends can figure out when to twiddle the
mapping attributes and map with/without encryption?

These API changes place an undue burden on developers that don't even
care about SME.

  reply	other threads:[~2016-05-10 13:44 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 [this message]
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 ` [RFC PATCH v1 00/18] x86: Secure Memory Encryption (AMD) Andy Lutomirski
2016-04-27 20:10   ` 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
2016-04-26 22:47 ` [RFC PATCH v1 10/18] x86/efi: Access EFI related tables in the clear Tom Lendacky

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