| Message ID | 20250318013238.5732-1-yan.y.zhao@intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Small changes related to prefetch and spurious faults | expand |
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 6365eb6c1390..d219ecd4ac5b 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1139,8 +1139,10 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu, if (is_shadow_present_pte(iter->old_spte) && (fault->prefetch || is_access_allowed(fault, iter->old_spte)) && - is_last_spte(iter->old_spte, iter->level)) + is_last_spte(iter->old_spte, iter->level)) { + WARN_ON_ONCE(fault->pfn != spte_to_pfn(iter->old_spte)); return RET_PF_SPURIOUS; + } if (unlikely(!fault->slot)) new_spte = make_mmio_spte(vcpu, iter->gfn, ACC_ALL);
Add a WARN() to assert that KVM does _not_ change the PFN of a shadow-present SPTE during spurious fault handling. KVM should _never_ change the PFN of a shadow-present SPTE and TDP MMU already BUG()s on this. However, spurious faults just return early before the existing BUG() could be hit. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Yan Zhao <yan.y.zhao@intel.com> --- arch/x86/kvm/mmu/tdp_mmu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)