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From: Matt Fleming <matt@codeblueprint.co.uk>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: "Borislav Petkov" <bp@alien8.de>,
	"Leif Lindholm" <leif.lindholm@linaro.org>,
	"Mark Salter" <msalter@redhat.com>,
	"Daniel Kiper" <daniel.kiper@oracle.com>,
	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>,
	"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>,
	"Ard Biesheuvel" <ard.biesheuvel@linaro.org>
Subject: Re: [RFC PATCH v1 10/18] x86/efi: Access EFI related tables in the clear
Date: Wed, 8 Jun 2016 11:07:13 +0100	[thread overview]
Message-ID: <20160608100713.GU2658@codeblueprint.co.uk> (raw)
In-Reply-To: <5746FE16.9070408@amd.com>

(Sorry for the delay)

On Thu, 26 May, at 08:45:58AM, Tom Lendacky wrote:
> 
> The patch in question is patch 6/18 where PAGE_KERNEL is changed to
> include the _PAGE_ENC attribute (the encryption mask). This now
> makes FIXMAP_PAGE_NORMAL contain the encryption mask while
> FIXMAP_PAGE_IO does not. In this way, anything mapped using the
> early_ioremap call won't be mapped encrypted.

There are semantics attached to early_ioremap() that do not apply in
this case; that you're mapping an MMIO region but for EFI we just care
about noting where the firmware (not the kernel) populated the region
with data. Similar problems exist for other early boot code such as
the devicetree stuff.

early_ioremap() is not the answer.

What you really want is just some way to distinguish kernel-owned
regions from those owned by "somebody else".

I have no problem updating early_memremap() to take a @flags argument
to make that distinction, provided that the naming is generic and not
tied to AMD's SME technology via an "sme" prefix/suffix.

And making it generic should allow it to be easily sprinkled into the
shared architecture code in drivers/firmware/efi/ without issue.

I'm going to follow up with some additional comments/questions on
PATCH 10.

  reply	other threads:[~2016-06-08 10:07 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 [this message]
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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