Re: [PATCHv5 02/19] mm: Do not use zero page in encrypted pages

[Dave Hansen]

On 07/17/2018 04:20 AM, Kirill A. Shutemov wrote:
> Zero page is not encrypted and putting it into encrypted VMA produces
> garbage.
> 
> We can map zero page with KeyID-0 into an encrypted VMA, but this would
> be violation security boundary between encryption domains.

Why?  How is it a violation?

It only matters if they write secrets.  They can't write secrets to the
zero page.

Is this only because you accidentally inherited ->vm_page_prot on the
zero page PTE?