diff options
| author |   Yan Zhao <yan.y.zhao@intel.com> | 2025-03-18 09:32:38 +0800 |
|---|---|---|
| committer |   Sean Christopherson <seanjc@google.com> | 2025-04-28 11:03:06 -0700 |
| commit | 988da7820206405ef2d8afde83c2c2cd7af503a2 (patch) | |
| tree | 0322d35ef5f1db0377a3306c25b7f7adeea5aa21 | |
| parent | KVM: x86/tdp_mmu: Merge prefetch and access checks for spurious faults (diff) | |
| download | linux-rng-988da7820206405ef2d8afde83c2c2cd7af503a2.tar.xz linux-rng-988da7820206405ef2d8afde83c2c2cd7af503a2.zip | |
KVM: x86/tdp_mmu: WARN if PFN changes for spurious faults
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>
Link: https://lore.kernel.org/r/20250318013238.5732-1-yan.y.zhao@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_mmu.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index d16e3e6e46a5..1e2db4917459 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1155,8 +1155,10 @@ 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); |