From: Tom Lendacky <thomas.lendacky@amd.com>
To: Matt Fleming <matt@codeblueprint.co.uk>
Cc: "Andy Lutomirski" <luto@amacapital.net>,
kasan-dev <kasan-dev@googlegroups.com>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
iommu@lists.linux-foundation.org,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
"Jonathan Corbet" <corbet@lwn.net>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"Alexander Potapenko" <glider@google.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Dmitry Vyukov" <dvyukov@google.com>,
"Arnd Bergmann" <arnd@arndb.de>, "Joerg Roedel" <joro@8bytes.org>,
"Andrey Ryabinin" <aryabinin@virtuozzo.com>,
"H. Peter Anvin" <hpa@zytor.com>, "X86 ML" <x86@kernel.org>,
"kvm list" <kvm@vger.kernel.org>,
"Dave Young" <dyoung@redhat.com>
Subject: Re: [RFC PATCH v2 11/20] mm: Access BOOT related data in the clear
Date: Thu, 15 Sep 2016 11:52:05 -0500 [thread overview]
Message-ID: <d25531f2-cc17-aa65-c6b9-f72e97b69b00@amd.com> (raw)
In-Reply-To: <20160915095709.GB16797@codeblueprint.co.uk>
On 09/15/2016 04:57 AM, Matt Fleming wrote:
> On Wed, 14 Sep, at 09:20:44AM, Tom Lendacky wrote:
>> On 09/12/2016 11:55 AM, Andy Lutomirski wrote:
>>> On Aug 22, 2016 6:53 PM, "Tom Lendacky" <thomas.lendacky@amd.com> wrote:
>>>>
>>>> BOOT data (such as EFI related data) is not encyrpted when the system is
>>>> booted and needs to be accessed as non-encrypted. Add support to the
>>>> early_memremap API to identify the type of data being accessed so that
>>>> the proper encryption attribute can be applied. Currently, two types
>>>> of data are defined, KERNEL_DATA and BOOT_DATA.
>>>
>>> What happens when you memremap boot services data outside of early
>>> boot? Matt just added code that does this.
>>>
>>> IMO this API is not so great. It scatters a specialized consideration
>>> all over the place. Could early_memremap not look up the PA to figure
>>> out what to do?
>>
>> Yes, I could see if the PA falls outside of the kernel usable area and,
>> if so, remove the memory encryption attribute from the mapping (for both
>> early_memremap and memremap).
>>
>> Let me look into that, I would prefer something along that line over
>> this change.
>
> So, the last time we talked about using the address to figure out
> whether to encrypt/decrypt you said,
>
> "I looked into this and this would be a large change also to parse
> tables and build lists."
>
> Has something changed that makes this approach easier?
The original idea of parsing the tables and building a list was
a large change. This approach would be simpler by just checking if
the PA is outside the kernel usable area, and if so, removing the
encryption bit.
>
> And again, you need to be careful with the EFI kexec code paths, since
> you've got a mixture of boot and kernel data being passed. In
> particular the EFI memory map is allocated by the firmware on first
> boot (BOOT_DATA) but by the kernel on kexec (KERNEL_DATA).
>
> That's one of the reasons I suggested requiring the caller to decide
> on BOOT_DATA vs KERNEL_DATA - when you start looking at kexec the
> distinction isn't easily made.
Yeah, for kexec I think I'll need to make sure that everything looks
like it came from the BIOS/UEFI/bootloader. If all of the kexec
pieces are allocated with un-encrypted memory, then the boot path
should remain the same. That's the piece I need to investigate
further.
Thanks,
Tom
>
next prev parent reply other threads:[~2016-09-15 17:08 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-22 22:35 [RFC PATCH v2 00/20] x86: Secure Memory Encryption (AMD) Tom Lendacky
2016-08-22 22:35 ` [RFC PATCH v2 01/20] x86: Documentation for AMD Secure Memory Encryption (SME) Tom Lendacky
2016-09-02 8:50 ` Borislav Petkov
2016-09-07 14:02 ` Tom Lendacky
2016-09-07 15:23 ` Borislav Petkov
2016-08-22 22:35 ` [RFC PATCH v2 02/20] x86: Set the write-protect cache mode for full PAT support Tom Lendacky
2016-08-25 3:58 ` Borislav Petkov
2016-08-22 22:35 ` [RFC PATCH v2 03/20] x86: Secure Memory Encryption (SME) build enablement Tom Lendacky
2016-09-02 11:03 ` Borislav Petkov
2016-09-07 14:03 ` Tom Lendacky
2016-08-22 22:36 ` [RFC PATCH v2 04/20] x86: Secure Memory Encryption (SME) support Tom Lendacky
2016-08-25 13:04 ` Thomas Gleixner
2016-08-30 13:19 ` Tom Lendacky
2016-08-30 14:57 ` Andy Lutomirski
2016-08-31 13:26 ` Tom Lendacky
2016-08-22 22:36 ` [RFC PATCH v2 05/20] x86: Add the Secure Memory Encryption cpu feature Tom Lendacky
2016-09-02 14:09 ` Borislav Petkov
2016-09-07 14:07 ` Tom Lendacky
2016-08-22 22:36 ` [RFC PATCH v2 06/20] x86: Handle reduction in physical address size with SME Tom Lendacky
2016-08-22 22:36 ` [RFC PATCH v2 07/20] x86: Provide general kernel support for memory encryption Tom Lendacky
2016-09-02 18:14 ` Borislav Petkov
2016-09-07 14:11 ` Tom Lendacky
2016-09-05 8:48 ` Borislav Petkov
2016-09-07 14:16 ` Tom Lendacky
2016-09-05 15:22 ` Borislav Petkov
2016-09-07 14:19 ` Tom Lendacky
2016-09-06 9:31 ` Borislav Petkov
2016-09-07 14:30 ` Tom Lendacky
2016-09-07 15:55 ` Borislav Petkov
2016-09-08 13:26 ` Tom Lendacky
2016-09-08 13:55 ` Borislav Petkov
2016-09-12 13:43 ` Tom Lendacky
2016-08-22 22:37 ` [RFC PATCH v2 08/20] x86: Extend the early_memmap support with additional attrs Tom Lendacky
2016-08-22 22:37 ` [RFC PATCH v2 09/20] x86: Add support for early encryption/decryption of memory Tom Lendacky
2016-09-06 16:12 ` Borislav Petkov
2016-08-22 22:37 ` [RFC PATCH v2 10/20] x86: Insure that memory areas are encrypted when possible Tom Lendacky
2016-09-09 15:53 ` Borislav Petkov
2016-09-12 15:05 ` Tom Lendacky
2016-09-12 16:33 ` Borislav Petkov
2016-09-14 14:11 ` Tom Lendacky
2016-08-22 22:37 ` [RFC PATCH v2 11/20] mm: Access BOOT related data in the clear Tom Lendacky
2016-09-09 16:38 ` Borislav Petkov
2016-09-12 15:14 ` Tom Lendacky
2016-09-12 16:35 ` Borislav Petkov
2016-09-12 16:55 ` Andy Lutomirski
2016-09-14 14:20 ` Tom Lendacky
2016-09-15 9:57 ` Matt Fleming
2016-09-15 16:52 ` Tom Lendacky [this message]
2016-08-22 22:37 ` [RFC PATCH v2 12/20] x86: Add support for changing memory encryption attribute Tom Lendacky
2016-09-09 17:23 ` Borislav Petkov
2016-09-12 15:41 ` Tom Lendacky
2016-09-12 16:41 ` Borislav Petkov
2016-08-22 22:37 ` [RFC PATCH v2 13/20] x86: Decrypt trampoline area if memory encryption is active Tom Lendacky
2016-09-09 17:34 ` Borislav Petkov
2016-09-12 15:43 ` Tom Lendacky
2016-08-22 22:38 ` [RFC PATCH v2 14/20] x86: DMA support for memory encryption Tom Lendacky
2016-09-12 10:58 ` Borislav Petkov
2016-09-14 13:36 ` Tom Lendacky
2016-08-22 22:38 ` [RFC PATCH v2 15/20] iommu/amd: AMD IOMMU " Tom Lendacky
2016-09-12 11:45 ` Borislav Petkov
2016-09-14 13:45 ` Tom Lendacky
2016-09-14 14:41 ` Borislav Petkov
2016-09-15 16:57 ` Tom Lendacky
2016-09-16 7:08 ` Borislav Petkov
2016-08-22 22:38 ` [RFC PATCH v2 16/20] x86: Check for memory encryption on the APs Tom Lendacky
2016-09-12 12:17 ` Borislav Petkov
2016-09-14 13:50 ` Tom Lendacky
2016-09-12 16:43 ` Borislav Petkov
2016-09-14 14:12 ` Tom Lendacky
2016-08-22 22:38 ` [RFC PATCH v2 17/20] x86: Do not specify encrypted memory for VGA mapping Tom Lendacky
2016-08-22 22:38 ` [RFC PATCH v2 18/20] x86/kvm: Enable Secure Memory Encryption of nested page tables Tom Lendacky
2016-09-12 14:35 ` Borislav Petkov
2016-09-14 14:02 ` Tom Lendacky
2016-08-22 22:38 ` [RFC PATCH v2 19/20] x86: Access the setup data through debugfs un-encrypted Tom Lendacky
2016-09-12 16:59 ` Borislav Petkov
2016-09-14 14:29 ` Tom Lendacky
2016-09-14 14:51 ` Borislav Petkov
2016-09-15 17:08 ` Tom Lendacky
2016-09-16 7:11 ` Borislav Petkov
2016-08-22 22:39 ` [RFC PATCH v2 20/20] x86: Add support to make use of Secure Memory Encryption Tom Lendacky
2016-09-12 17:08 ` Borislav Petkov
2016-09-14 14:31 ` Tom Lendacky
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