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

[Tom Lendacky]

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@xxxxxxxxxxxxx>

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

>