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

[Thomas Gleixner]

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@xxxxxxxxxxxxx>