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SubjectRe: [PATCH 15/16] KVM: x86/mmu: Initialize kvm_page_fault's pfn and hva to error values
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On 28/02/2024 3:41 pm, Sean Christopherson wrote:
> Explicitly set "pfn" and "hva" to error values in kvm_mmu_do_page_fault()
> to harden KVM against using "uninitialized" values. In quotes because the
> fields are actually zero-initialized, and zero is a legal value for both
> page frame numbers and virtual addresses. E.g. failure to set "pfn" prior
> to creating an SPTE could result in KVM pointing at physical address '0',
> which is far less desirable than KVM generating a SPTE with reserved PA
> bits set and thus effectively killing the VM.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> arch/x86/kvm/mmu/mmu_internal.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
> index 74736d517e74..67e32dec9424 100644
> --- a/arch/x86/kvm/mmu/mmu_internal.h
> +++ b/arch/x86/kvm/mmu/mmu_internal.h
> @@ -307,6 +307,9 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
> .req_level = PG_LEVEL_4K,
> .goal_level = PG_LEVEL_4K,
> .is_private = err & PFERR_PRIVATE_ACCESS,
> +
> + .pfn = KVM_PFN_ERR_FAULT,
> + .hva = KVM_HVA_ERR_BAD,
> };
> int r;
>

Reviewed-by: Kai Huang <kai.huang@intel.com>

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