From b850841a53c56665c1f623edd429b3fc1578e9a4 Mon Sep 17 00:00:00 2001 From: Dmytro Maluka Date: Fri, 26 Sep 2025 15:51:39 +0200 Subject: [PATCH] KVM: x86/mmu: Skip MMIO SPTE invalidation if enable_mmio_caching=0 If MMIO caching is disabled, there are no MMIO SPTEs to invalidate, so the costly zapping of all pages is unnecessary even in the unlikely case when the MMIO generation number has wrapped. Signed-off-by: Dmytro Maluka Link: https://lore.kernel.org/r/20250926135139.1597781-1-dmaluka@chromium.org Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu/mmu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 667d66cf76d5e..18d69d48bc55a 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -7364,6 +7364,9 @@ void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen) { WARN_ON_ONCE(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS); + if (!enable_mmio_caching) + return; + gen &= MMIO_SPTE_GEN_MASK; /* -- 2.47.3