On Wed, Sep 07, 2016 at 04:17:09PM +1000, Paul Mackerras wrote: > This replaces a 2-D search through an array with a simple 8-bit table > lookup for determining the actual and/or base page size for a HPT entry. > > The encoding in the second doubleword of the HPTE is designed to encode > the actual and base page sizes without using any more bits than would be > needed for a 4k page number, by using between 1 and 8 low-order bits of > the RPN (real page number) field to encode the page sizes. A single > "large page" bit in the first doubleword indicates that these low-order > bits are to be interpreted like this. > > We can determine the page sizes by using the low-order 8 bits of the RPN > to look up a 256-entry table. For actual page sizes less than 1MB, some > of the upper bits of these 8 bits are going to be real address bits, but > we can cope with that by replicating the entries for those smaller page > sizes. > > While we're at it, let's move the hpte_page_size() and hpte_base_page_size() > functions from a KVM-specific header to a header for 64-bit HPT systems, > since this computation doesn't have anything specifically to do with KVM. > > Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx> > --- > v2: added more comments as suggested by Aneesh > > arch/powerpc/include/asm/book3s/64/mmu-hash.h | 37 ++++++++++++ > arch/powerpc/include/asm/kvm_book3s_64.h | 87 +++------------------------ > arch/powerpc/include/asm/mmu.h | 1 + > arch/powerpc/mm/hash_native_64.c | 42 +------------ > arch/powerpc/mm/hash_utils_64.c | 55 +++++++++++++++++ This of course touches two maintainers' areas. Michael and Paolo, how do you want to proceed here? Can this just go through Michael's tree? Or should I make a topic branch off Linus' tree that you can both pull, or should I split the patch into two (i.e. everything except the kvm_book3s_64.h change in the first patch, and the kvm_book3s_64.h change in the second) and get Michael to put the first one in a topic branch that I can then pull and apply the second patch onto? Thanks, Paul. -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
