----- Original Message ----- > From: "Bandan Das" <bsd@xxxxxxxxxx> > To: "Paolo Bonzini" <pbonzini@xxxxxxxxxx> > Cc: linux-kernel@xxxxxxxxxxxxxxx, kvm@xxxxxxxxxxxxxxx, david@xxxxxxxxxx > Sent: Wednesday, April 12, 2017 7:35:16 AM > Subject: Re: [PATCH 4/6] kvm: nVMX: support EPT accessed/dirty bits > > Paolo Bonzini <pbonzini@xxxxxxxxxx> writes: > ... > > accessed_dirty = have_ad ? PT_GUEST_ACCESSED_MASK : 0; > > + > > + /* > > + * FIXME: on Intel processors, loads of the PDPTE registers for PAE > > paging > > + * by the MOV to CR instruction are treated as reads and do not cause the > > + * processor to set the dirty flag in tany EPT paging-structure entry. > > + */ > > Minor typo: "in any EPT paging-structure entry". > > > + nested_access = (have_ad ? PFERR_WRITE_MASK : 0) | PFERR_USER_MASK; > > + > > pt_access = pte_access = ACC_ALL; > > ++walker->level; > > > > @@ -338,7 +337,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker > > *walker, > > walker->pte_gpa[walker->level - 1] = pte_gpa; > > > > real_gfn = mmu->translate_gpa(vcpu, gfn_to_gpa(table_gfn), > > - PFERR_USER_MASK|PFERR_WRITE_MASK, > > + nested_access, > > &walker->fault); > > I can't seem to understand the significance of this change (or for that > matter what was before this change). > > mmu->translate_gpa() just returns gfn_to_gpa(table_gfn), right ? For EPT it is, you're right it's fishy. The "nested_access" should be computed in translate_nested_gpa, which is where kvm->arch.nested_mmu (non-EPT) requests to access kvm->arch.mmu (EPT). In practice we need to define a new function vcpu->arch.mmu.gva_to_gpa_nested that computes the nested_access and calls cpu->arch.mmu.gva_to_gpa. Thanks, Paolo
