From 38b0ac47169b981bd40226f16f17d8a098c81309 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 31 Oct 2024 10:06:33 -0700 Subject: [PATCH] KVM: x86/mmu: Demote the WARN on yielded in xxx_cond_resched() to KVM_MMU_WARN_ON Convert the WARN in tdp_mmu_iter_cond_resched() that the iterator hasn't already yielded to a KVM_MMU_WARN_ON() so the code is compiled out for production kernels (assuming production kernels disable KVM_PROVE_MMU). Checking for a needed reschedule is a hot path, and KVM sanity checks iter->yielded in several other less-hot paths, i.e. the odds of KVM not flagging that something went sideways are quite low. Furthermore, the odds of KVM not noticing *and* the WARN detecting something worth investigating are even lower. Link: https://lore.kernel.org/r/20241031170633.1502783-3-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu/tdp_mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 8170b16b91c3..ef44dcba1ecb 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -656,7 +656,7 @@ static inline bool __must_check tdp_mmu_iter_cond_resched(struct kvm *kvm, struct tdp_iter *iter, bool flush, bool shared) { - WARN_ON_ONCE(iter->yielded); + KVM_MMU_WARN_ON(iter->yielded); if (!need_resched() && !rwlock_needbreak(&kvm->mmu_lock)) return false; -- 2.50.1