+static bool quickly_check_mmio_pf(struct kvm_vcpu *vcpu, u64 addr, bool direct)
+{
+ if (direct)
+ return vcpu_match_mmio_gpa(vcpu, addr);
+
+ return vcpu_match_mmio_gva(vcpu, addr);
+}
+
+
+/*
+ * On direct hosts, the last spte is only allows two states
+ * for mmio page fault:
+ * - It is the mmio spte
+ * - It is zapped or it is being zapped.
+ *
+ * This function completely checks the spte when the last spte
+ * is not the mmio spte.
+ */
+static bool check_direct_spte_mmio_pf(u64 spte)
+{
+ return __check_direct_spte_mmio_pf(spte);
+}
+
+static u64 walk_shadow_page_get_mmio_spte(struct kvm_vcpu *vcpu, u64 addr)
+{
+ struct kvm_shadow_walk_iterator iterator;
+ u64 spte = 0ull;
+
+ walk_shadow_page_lockless_begin(vcpu);
+ for_each_shadow_entry_lockless(vcpu, addr, iterator, spte)
+ if (!is_shadow_present_pte(spte))
+ break;
+ walk_shadow_page_lockless_end(vcpu);
+
+ return spte;
+}
+
+/*
+ * If it is a real mmio page fault, return 1 and emulat the instruction
+ * directly, return 0 to let CPU fault again on the address, -1 is
+ * returned if bug is detected.
+ */
+int handle_mmio_page_fault_common(struct kvm_vcpu *vcpu, u64 addr, bool direct)
+{
+ u64 spte;
+
+ if (quickly_check_mmio_pf(vcpu, addr, direct))
+ return 1;
+
+ spte = walk_shadow_page_get_mmio_spte(vcpu, addr);
+
+ if (is_mmio_spte(spte)) {
+ gfn_t gfn = get_mmio_spte_gfn(spte);
+ unsigned access = get_mmio_spte_access(spte);
+
+ if (direct)
+ addr = 0;
+ vcpu_cache_mmio_info(vcpu, addr, gfn, access);
+ return 1;
+ }
+
+ /*
+ * It's ok if the gva is remapped by other cpus on shadow guest,
+ * it's a BUG if the gfn is not a mmio page.
+ */
+ if (direct && !check_direct_spte_mmio_pf(spte))
+ return -1;
+
+ /*
+ * If the page table is zapped by other cpus, let CPU fault again on
+ * the address.
+ */
+ return 0;
+}
+EXPORT_SYMBOL_GPL(handle_mmio_page_fault_common);
+
+static int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr,
+ u32 error_code, bool direct)
+{
+ int ret;
+
+ ret = handle_mmio_page_fault_common(vcpu, addr, direct);
+ WARN_ON(ret < 0);
+ return ret;
+}
+