On Wed, Jun 13, 2018 at 06:41:21PM +0000, Dave Hansen wrote: > On 06/12/2018 07:39 AM, Kirill A. Shutemov wrote: > > arch/x86/include/asm/mktme.h | 6 + > > arch/x86/mm/init_64.c | 6 + > > arch/x86/mm/mktme.c | 444 +++++++++++++++++++++++++++++++++++ > > 3 files changed, 456 insertions(+) > > Can we not do any better than 400 lines of new open-coded pagetable > hacking?
It's not pretty, but I don't see much options. I first tried to modify routines that initialize/modify/remove parts of direct mapping to keep all per-KeyID direct mappings in sync from start. But it didn't really fly. We need to initialize direct mapping very early when we don't have a way to allocated page in a usual way. We have very limited pool of pre-allocated pages to allocate page tables from and it's not able to satisfy demand for multiple direct mappings. So I had to go with syncing it later on. When we have working page allocator. Regarding open-codeness, we need to walk two subtrees in lock steps. I don't see how get mm/pagewalk.c to work in such use case. (And I don't really like callback-based pagewalker.) -- Kirill A. Shutemov
