[v3,0/2] Refactor super page shattering

Message

Xia, Hongyan Dec. 11, 2019, 10:58 a.m. UTC

map_pages_to_xen and modify_xen_mappings use almost exactly the same
page shattering logic, and the code is mingled with other PTE
manipulations so it is less obvious that the intention is page
shattering. Factor out the functions to make them reusable and to make
the intention more obvious.

Of course, there is not much difference between the shattering logic of
each level, so we could further turn the per-level functions into a
single macro, although this is not that simple since we have per-level
functions and macros all over the place and there are slight differences
between levels. Keep it per-level for now.

tree:
https://xenbits.xen.org/git-http/people/hx242/xen.git shatter-refactor

---
Changes in v3:
- style and indentation fixes.

Changes in v2:
- rebase.
- improve asm code.
- avoid stale values when taking the lock.
- move allocation of PTE tables inside the shatter function.

Hongyan Xia (2):
  x86/mm: factor out the code for shattering an l3 PTE
  x86/mm: factor out the code for shattering an l2 PTE

 xen/arch/x86/mm.c | 194 +++++++++++++++++++++++-----------------------
 1 file changed, 98 insertions(+), 96 deletions(-)