Hello Alexandre, On Mon, May 04, 2020 at 04:57:57PM +0200, Alexandre Chartre wrote: > This is part II of ASI RFC v4. Please refer to the cover letter of > part I for an overview the ASI RFC. > > https://lore.kernel.org/lkml/20200504144939.11318-1-alexandre.chartre@xxxxxxxxxx/ > > This part introduces decorated page-table which encapsulate native page > table (e.g. a PGD) in order to provide convenient page-table management > functions, such as tracking address range mapped in a page-table or > safely handling references to another page-table. > > Decorated page-table can then be used to easily create and manage page > tables to be used with ASI. It will be used by the ASI test driver (see > part III) and later by KVM ASI. > > Decorated page-table is independent of ASI, and can potentially be used > anywhere a page-table is needed. This is very impressive work! I wonder why did you decide to make dpt x86-specific? Unless I've missed simething, the dpt implementation does not rely on anything architecture specific and can go straight to linux/mm. Another thing that comes to mind is that we already have a very decorated page table, which is mm_struct. I admit that my attempt to split out the core page table bits from the mm_struct [1] didn't went far, but I still think we need a first class abstraction for the page table that will be used by both user memory management and the management of the reduced kernel address spaces. [1] https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/log/?h=pg_table/v0.0 > Thanks, > > alex. > > ----- > > Alexandre Chartre (13): > mm/x86: Introduce decorated page-table (dpt) > mm/dpt: Track buffers allocated for a decorated page-table > mm/dpt: Add decorated page-table entry offset functions > mm/dpt: Add decorated page-table entry allocation functions > mm/dpt: Add decorated page-table entry set functions > mm/dpt: Functions to populate a decorated page-table from a VA range > mm/dpt: Helper functions to map module into a decorated page-table > mm/dpt: Keep track of VA ranges mapped in a decorated page-table > mm/dpt: Functions to clear decorated page-table entries for a VA range > mm/dpt: Function to copy page-table entries for percpu buffer > mm/dpt: Add decorated page-table remap function > mm/dpt: Handle decorated page-table mapped range leaks and overlaps > mm/asi: Function to init decorated page-table with ASI core mappings > > arch/x86/include/asm/asi.h | 2 + > arch/x86/include/asm/dpt.h | 89 +++ > arch/x86/mm/Makefile | 2 +- > arch/x86/mm/asi.c | 57 ++ > arch/x86/mm/dpt.c | 1051 ++++++++++++++++++++++++++++++++++++ > 5 files changed, 1200 insertions(+), 1 deletion(-) > create mode 100644 arch/x86/include/asm/dpt.h > create mode 100644 arch/x86/mm/dpt.c > > -- > 2.18.2 > -- Sincerely yours, Mike.
