+DEFINE_STATIC_KEY_FALSE(enable_evmcs);
+
+#define current_evmcs ((struct hv_enlightened_vmcs *)this_cpu_read(current_vmcs))
+
+#define KVM_EVMCS_VERSION 1
+
+#if IS_ENABLED(CONFIG_HYPERV)
+static bool __read_mostly enlightened_vmcs = true;
+module_param(enlightened_vmcs, bool, 0444);
+
+static inline void evmcs_write64(unsigned long field, u64 value)
+{
+ u16 clean_field;
+ int offset = get_evmcs_offset(field, &clean_field);
+
+ if (offset < 0)
+ return;
+
+ *(u64 *)((char *)current_evmcs + offset) = value;
+
+ current_evmcs->hv_clean_fields &= ~clean_field;
+}
+
+static inline void evmcs_write32(unsigned long field, u32 value)
+{
+ u16 clean_field;
+ int offset = get_evmcs_offset(field, &clean_field);
+
+ if (offset < 0)
+ return;
+
+ *(u32 *)((char *)current_evmcs + offset) = value;
+ current_evmcs->hv_clean_fields &= ~clean_field;
+}
+
+static inline void evmcs_write16(unsigned long field, u16 value)
+{
+ u16 clean_field;
+ int offset = get_evmcs_offset(field, &clean_field);
+
+ if (offset < 0)
+ return;
+
+ *(u16 *)((char *)current_evmcs + offset) = value;
+ current_evmcs->hv_clean_fields &= ~clean_field;
+}
+
+static inline u64 evmcs_read64(unsigned long field)
+{
+ int offset = get_evmcs_offset(field, NULL);
+
+ if (offset < 0)
+ return 0;
+
+ return *(u64 *)((char *)current_evmcs + offset);
+}
+
+static inline u32 evmcs_read32(unsigned long field)
+{
+ int offset = get_evmcs_offset(field, NULL);
+
+ if (offset < 0)
+ return 0;
+
+ return *(u32 *)((char *)current_evmcs + offset);
+}
+
+static inline u16 evmcs_read16(unsigned long field)
+{
+ int offset = get_evmcs_offset(field, NULL);
+
+ if (offset < 0)
+ return 0;
+
+ return *(u16 *)((char *)current_evmcs + offset);
+}
+
+static void evmcs_load(u64 phys_addr)
+{
+ struct hv_vp_assist_page *vp_ap =
+ hv_get_vp_assist_page(smp_processor_id());
+
+ vp_ap->current_nested_vmcs = phys_addr;
+ vp_ap->enlighten_vmentry = 1;
+}
+
+static void evmcs_sanitize_exec_ctrls(struct vmcs_config *vmcs_conf)
+{
+ /*
+ * Enlightened VMCSv1 doesn't support these:
+ *
+ * POSTED_INTR_NV = 0x00000002,
+ * GUEST_INTR_STATUS = 0x00000810,
+ * APIC_ACCESS_ADDR = 0x00002014,
+ * POSTED_INTR_DESC_ADDR = 0x00002016,
+ * EOI_EXIT_BITMAP0 = 0x0000201c,
+ * EOI_EXIT_BITMAP1 = 0x0000201e,
+ * EOI_EXIT_BITMAP2 = 0x00002020,
+ * EOI_EXIT_BITMAP3 = 0x00002022,
+ */
+ vmcs_conf->pin_based_exec_ctrl &= ~PIN_BASED_POSTED_INTR;
+ vmcs_conf->cpu_based_2nd_exec_ctrl &=
+ ~SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY;
+ vmcs_conf->cpu_based_2nd_exec_ctrl &=
+ ~SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
+ vmcs_conf->cpu_based_2nd_exec_ctrl &=
+ ~SECONDARY_EXEC_APIC_REGISTER_VIRT;
+
+ /*
+ * GUEST_PML_INDEX = 0x00000812,
+ * PML_ADDRESS = 0x0000200e,
+ */
+ vmcs_conf->cpu_based_2nd_exec_ctrl &= ~SECONDARY_EXEC_ENABLE_PML;
+
+ /* VM_FUNCTION_CONTROL = 0x00002018, */
+ vmcs_conf->cpu_based_2nd_exec_ctrl &= ~SECONDARY_EXEC_ENABLE_VMFUNC;
+
+ /*
+ * EPTP_LIST_ADDRESS = 0x00002024,
+ * VMREAD_BITMAP = 0x00002026,
+ * VMWRITE_BITMAP = 0x00002028,
+ */
+ vmcs_conf->cpu_based_2nd_exec_ctrl &= ~SECONDARY_EXEC_SHADOW_VMCS;
+
+ /*
+ * TSC_MULTIPLIER = 0x00002032,
+ */
+ vmcs_conf->cpu_based_2nd_exec_ctrl &= ~SECONDARY_EXEC_TSC_SCALING;
+
+ /*
+ * PLE_GAP = 0x00004020,
+ * PLE_WINDOW = 0x00004022,
+ */
+ vmcs_conf->cpu_based_2nd_exec_ctrl &= ~SECONDARY_EXEC_PAUSE_LOOP_EXITING;
+
+ /*
+ * VMX_PREEMPTION_TIMER_VALUE = 0x0000482E,
+ */
+ vmcs_conf->pin_based_exec_ctrl &= ~PIN_BASED_VMX_PREEMPTION_TIMER;
+
+ /*
+ * GUEST_IA32_PERF_GLOBAL_CTRL = 0x00002808,
+ * HOST_IA32_PERF_GLOBAL_CTRL = 0x00002c04,
+ */
+ vmcs_conf->vmexit_ctrl &= ~VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL;
+ vmcs_conf->vmentry_ctrl &= ~VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL;
+
+ /*
+ * Currently unsupported in KVM:
+ * GUEST_IA32_RTIT_CTL = 0x00002814,
+ */
+}
+#else /* !IS_ENABLED(CONFIG_HYPERV) */
+static inline void evmcs_write64(unsigned long field, u64 value) {}
+static inline void evmcs_write32(unsigned long field, u32 value) {}
+static inline void evmcs_write16(unsigned long field, u16 value) {}
+static inline u64 evmcs_read64(unsigned long field) { return 0; }
+static inline u32 evmcs_read32(unsigned long field) { return 0; }
+static inline u16 evmcs_read16(unsigned long field) { return 0; }
+static inline void evmcs_load(u64 phys_addr) {}
+static inline void evmcs_sanitize_exec_ctrls(struct vmcs_config *vmcs_conf) {}
+#endif /* IS_ENABLED(CONFIG_HYPERV) */
+