linux-kernel - Re: [PATCH v10 00/38] x86: Secure Memory Encryption (AMD)

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Date:   Tue, 18 Jul 2017 09:02:08 -0500
From:   Tom Lendacky <thomas.lendacky@....com>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org,
        linux-arch@...r.kernel.org, linux-efi@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-mm@...ck.org, kvm@...r.kernel.org,
        kasan-dev@...glegroups.com,
        Radim Krčmář <rkrcmar@...hat.com>,
        Arnd Bergmann <arnd@...db.de>,
        Jonathan Corbet <corbet@....net>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Andy Lutomirski <luto@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Alexander Potapenko <glider@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Rik van Riel <riel@...hat.com>,
        Larry Woodman <lwoodman@...hat.com>,
        Dave Young <dyoung@...hat.com>,
        Toshimitsu Kani <toshi.kani@....com>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Brijesh Singh <brijesh.singh@....com>,
        iommu@...ts.linux-foundation.org, Joerg Roedel <joro@...tes.org>,
        kexec@...ts.infradead.org, xen-devel@...ts.xen.org,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Juergen Gross <jgross@...e.com>
Subject: Re: [PATCH v10 00/38] x86: Secure Memory Encryption (AMD)

On 7/18/2017 7:03 AM, Thomas Gleixner wrote:
> On Mon, 17 Jul 2017, Tom Lendacky wrote:
>> This 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.
>>
>> The SME feature is identified through a CPUID function and enabled through
>> the SYSCFG MSR. Once enabled, page table entries will determine how the
>> memory is accessed. If a page table entry has the memory encryption mask set,
>> then that memory will be accessed as encrypted memory. The memory encryption
>> mask (as well as other related information) is determined from settings
>> returned through the same CPUID function that identifies the presence of the
>> feature.
>>
>> The approach that this patch series takes is to encrypt everything possible
>> starting early in the boot where the kernel is encrypted. Using the page
>> table macros the encryption mask can be incorporated into all page table
>> entries and page allocations. By updating the protection map, userspace
>> allocations are also marked encrypted. Certain data must be accounted for
>> as having been placed in memory before SME was enabled (EFI, initrd, etc.)
>> and accessed accordingly.
>>
>> This patch series is a pre-cursor to another AMD processor feature called
>> Secure Encrypted Virtualization (SEV). The support for SEV will build upon
>> the SME support and will be submitted later. Details on SEV can be found
>> in the links below.
> 
> Well done series. Thanks to all people involved, especially Tom and Boris!
> It was a pleasure to review that.
> 
> Reviewed-by: Thomas Gleixner <tglx@...utronix.de>

A big thanks from me to everyone that helped review this.  I truly
appreciate all the time that everyone put into this - especially Boris,
who helped guide this series from the start.

Thanks,
Tom

>