Messages in this thread Patch in this message | | | Date | Sat, 26 Feb 2022 00:15:29 +0000 | Subject | [PATCH v3 11/28] KVM: x86/mmu: WARN if old _or_ new SPTE is REMOVED in non-atomic path | From | Sean Christopherson <> |
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WARN if the new_spte being set by __tdp_mmu_set_spte() is a REMOVED_SPTE, which is called out by the comment as being disallowed but not actually checked. Keep the WARN on the old_spte as well, because overwriting a REMOVED_SPTE in the non-atomic path is also disallowed (as evidence by lack of splats with the existing WARN).
Fixes: 08f07c800e9d ("KVM: x86/mmu: Flush TLBs after zap in TDP MMU PF handler") Cc: Ben Gardon <bgardon@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Ben Gardon <bgardon@google.com> --- arch/x86/kvm/mmu/tdp_mmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 8fbf3364f116..1dcdf1a4fcc1 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -640,13 +640,13 @@ static inline void __tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter, lockdep_assert_held_write(&kvm->mmu_lock); /* - * No thread should be using this function to set SPTEs to the + * No thread should be using this function to set SPTEs to or from the * temporary removed SPTE value. * If operating under the MMU lock in read mode, tdp_mmu_set_spte_atomic * should be used. If operating under the MMU lock in write mode, the * use of the removed SPTE should not be necessary. */ - WARN_ON(is_removed_spte(iter->old_spte)); + WARN_ON(is_removed_spte(iter->old_spte) || is_removed_spte(new_spte)); kvm_tdp_mmu_write_spte(iter->sptep, new_spte); -- 2.35.1.574.g5d30c73bfb-goog
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