[PATCH v10 00/38] x86: Secure Memory Encryption (AMD)

Tom Lendacky thomas.lendacky at amd.com
Tue Jul 18 07:02:08 PDT 2017

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 at linutronix.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.



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