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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