On 03/30/2012 08:01 AM, Xiao Guangrong wrote: > On 03/29/2012 09:07 PM, Avi Kivity wrote: > > > On 03/29/2012 11:22 AM, Xiao Guangrong wrote: > >> It can calculate the base gpa of the specified shadow page on any level, > >> let it instead of FNAME(get_level1_sp_gpa) > >> > >> > >> +static gpa_t FNAME(get_sp_gpa)(struct kvm_mmu_page *sp) > >> +{ > > > > Maybe worth adding a pte index and calling it get_spte_gpa(), depends on > > the next patches I guess. > > > > > Yes. > > But FNAME(get_sp_gpa) is still needed by FNAME(sync_page) path which sync > all sptes. I will introduce get_spte_gpa() as you mentioned which will be > used in invlpg path and in the later patch. > > > >> + int offset, shift; > >> + > >> + shift = PAGE_SHIFT - (PT_LEVEL_BITS - PT64_LEVEL_BITS) * sp->role.level; > >> + offset = sp->role.quadrant << shift; > > > > if you add '& ~PAGE_MASK' the compiler may be smart enough to drop the > > whole thing for 64-bit ptes. > > > > > Sorry. how to do that? offset = (sp->role.quadrant << shift) & ~PAGEMASK; the compiler should see that shift == PAGE_SHIFT and therefore anything in sp->role.quadrant will be masked out. > But if you want to remove the unnecessary workload, i will change it > like this: > > static gpa_t FNAME(get_sp_gpa)(struct kvm_mmu_page *sp) > { > int offset = 0; > > #if PTTYPE == 32 > int shift; > > shift = PAGE_SHIFT - (PT_LEVEL_BITS - PT64_LEVEL_BITS) * sp->role.level; > offset = sp->role.quadrant << shift; > #endif > return gfn_to_gpa(sp->gfn) + offset; > } That works too. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html