On 08/03/2012 05:25 AM, Nadav Har'El wrote: > On Thu, Aug 02, 2012, Xiao Guangrong wrote about "Re: [PATCH 02/10] nEPT: Add EPT tables support to paging_tmpl.h": >>> + #ifdef CONFIG_X86_64 >>> + #define PT_MAX_FULL_LEVELS 4 >>> + #define CMPXCHG cmpxchg >>> + #else >>> + #define CMPXCHG cmpxchg64 >>> + #define PT_MAX_FULL_LEVELS 2 >>> + #endif >> >> Missing the case of FULL_LEVELS == 3? Oh, you mentioned it >> as PAE case in the PATCH 0. > > I understood this differently (and it would not be surprising if > wrongly...): With nested EPT, we only deal with two *EPT* tables - > the shadowed page table and shadow page table are both EPT. > And EPT tables cannot have three levels - even if PAE is used. Or at least, > that's what I thought... > >> Note A/D bits are supported on new intel cpus, this function should be reworked >> for nept. I know you did not export this feather to guest, but we can reduce >> the difference between nept and other mmu models if A/D are supported. > > I'm not sure what you meant: If the access/dirty bits are supported in > newer cpus, do you think we *should* support them also in the processor > L1 processor, or are you saying that it would be easier to support them > because this is what the shadow page table code normally does anyway, > so *not* supporting them will take effort? I mean "it would be easier to support them because this is what the shadow page table code normally does anyway, so *not* supporting them will take effort" :) Then, we can drop "ifndef PTTYPT_EPT"... Actuality, we can redefine some bits (like PRSENT, WRTIABLE, DRITY...) to let the paging_tmpl code work for all models. > >>> +#if PTTYPE != PTTYPE_EPT >>> static int FNAME(walk_addr_nested)(struct guest_walker *walker, >>> struct kvm_vcpu *vcpu, gva_t addr, >>> u32 access) >>> @@ -335,6 +395,7 @@ static int FNAME(walk_addr_nested)(struc >>> return FNAME(walk_addr_generic)(walker, vcpu, &vcpu->arch.nested_mmu, >>> addr, access); >>> } >>> +#endif >>> >> >> Hmm, you do not need the special walking functions? > > Since these functions are static, the compiler warns me on every > function that is never used, so I had to #if them out... > > IIUC, you did not implement the functions (like walk_addr_nested) to translate L2's VA to L2's PA, yes? (it is needed for emulation.) -- 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
