On 02/22/2018 01:27 PM, Nadav Amit wrote: > Dave Hansen <dave.han...@linux.intel.com> wrote: >> From: Dave Hansen <dave.han...@linux.intel.com> >> In creating its page tables, the espfix code masks its PGTABLE_PROT >> value with the supported mask: __supported_pte_mask. This ensures >> that unsupported bits are not set in the final PTE. But, it also >> sets _PAGE_GLOBAL which we do not want for PTE. Use >> __default_kernel_pte_mask instead which clears _PAGE_GLOBAL for PTI. > > Can you please explain what is your concern? Exposing more gadgets for > speculative ROP attacks? > > Or is it a general rule of not exposing any kernel code &data more than > absolutely necessary?
I think it's good practice to just expose only the *minimal* amount of data necessary. It's easier to audit and less likely to expose things accidentall.
