tree c66b2f6788b8dc7444a28dd44354ef0c2f13db91
parent 3e79f6c82dcf4921726f18d9f380715284843407
author Adrian Danis <adanis@google.com> 1641253470 +0000
committer Commit Bot <commit-bot@chromium.org> 1641253470 +0000

[kernel][vm] Optimize protect ranges

Optimizes the protection of ranges by taking into account the previous
arch mmu flags for each range being modified. Knowing the previous
flags lets us skip manipulating the arch aspace in some circumstances
where we know it would be redundant.

In particular, without knowing the previous permissions if the new
permissions had WRITE, we would have to protect to the new permissions
minus WRITE, even if the new permissions were the same as the old ones.
Now this scenario can be identified and skipped.

Bug: 90014
Change-Id: I9d2bd3993eecb64cadb5bdcb0cb308fa8a9ea1c3
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/622424
Reviewed-by: Rasha Eqbal <rashaeqbal@google.com>
Commit-Queue: Adrian Danis <adanis@google.com>