On Sun, Dec 05, 2021 at 12:25:59AM +0200, Jarkko Sakkinen wrote: > On Wed, Dec 01, 2021 at 11:23:01AM -0800, Reinette Chatre wrote: > > === Summary === > > > > An SGX VMA can only be created if its permissions are the same or > > weaker than the Enclave Page Cache Map (EPCM) permissions. After VMA > > creation this rule continues to be enforced by the page fault handler. > > > > With SGX2 the EPCM permissions of a page can change after VMA > > creation resulting in the VMA exceeding the EPCM permissions and the > > page fault handler incorrectly blocking access. > > > > Enable the VMA's pages to remain accessible while ensuring that > > the page table entries are installed to match the EPCM permissions > > without exceeding the VMA perms issions. > > I don't understand what the short summary means in English, and the > commit message is way too bloated to make any conclusions. It really > needs a rewrite. > > These were the questions I could not find answer for: > > 1. Why it would be by any means safe to remove a permission check? > 2. Why not re-issuing mmap()'s is unfeasible? I.e. close existing > VMA's and mmap() new ones. 3. Isn't this an API/ABI break? /Jarkko
