Messages in this thread | | | Date | Wed, 14 Sep 2011 12:53:21 +0300 | From | Avi Kivity <> | Subject | Re: [PATCH v3 03/11] KVM: x86: retry non-page-table writing instruction |
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On 09/13/2011 09:24 PM, Xiao Guangrong wrote: > >> > >> +static bool retry_instruction(struct x86_emulate_ctxt *ctxt, > >> + unsigned long cr2, int emulation_type) > >> +{ > >> + if (!vcpu->arch.mmu.direct_map&& !mmu_is_nested(vcpu)) > >> + gpa = kvm_mmu_gva_to_gpa_write(vcpu, cr2, NULL); > > > > If mmu_is_nested() cr2 is an ngpa, we have to translate it to a gpa, no? > > > > Yeah, will fix it. > > And this bug also exists in the current code: it always uses L2 gpa to emulate > write operation.
Can you please send this fix separately, so it can be backported if needed?
> I guess the reason that it is not triggered is: the gpa of L2's shadow page can > not be touched by L2, it means no page table is write-protected by L2.
Yes. All real guest hypervisors will do that. But it is technically possible for a hypervisor to allow its guest access to the real page tables.
> > btw, I don't see mmu.direct_map initialized for nested npt? > > > > nested_svm_vmrun() -> nested_svm_init_mmu_context(): > static int nested_svm_init_mmu_context(struct kvm_vcpu *vcpu) > { > int r; > > r = kvm_init_shadow_mmu(vcpu,&vcpu->arch.mmu); > > vcpu->arch.mmu.set_cr3 = nested_svm_set_tdp_cr3; > vcpu->arch.mmu.get_cr3 = nested_svm_get_tdp_cr3; > vcpu->arch.mmu.get_pdptr = nested_svm_get_tdp_pdptr; > vcpu->arch.mmu.inject_page_fault = nested_svm_inject_npf_exit; > vcpu->arch.mmu.shadow_root_level = get_npt_level(); > vcpu->arch.walk_mmu =&vcpu->arch.nested_mmu; > > return r; > } > > It is initialized in kvm_init_shadow_mmu :-)
Yes, need new eyeglasses.
-- error compiling committee.c: too many arguments to function
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