kvm: vmx: Allow disabling virtual NMI support
To simplify testing of these rarely used code paths, add a module parameter
that turns it on. One eventinj.flat test (NMI after iret) fails when
loading kvm_intel with vnmi=0.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index bfee7f4..714a067 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -70,6 +70,9 @@
static bool __read_mostly enable_vpid = 1;
module_param_named(vpid, enable_vpid, bool, 0444);
+static bool __read_mostly enable_vnmi = 1;
+module_param_named(vnmi, enable_vnmi, bool, S_IRUGO);
+
static bool __read_mostly flexpriority_enabled = 1;
module_param_named(flexpriority, flexpriority_enabled, bool, S_IRUGO);
@@ -5236,6 +5239,10 @@
if (!kvm_vcpu_apicv_active(&vmx->vcpu))
pin_based_exec_ctrl &= ~PIN_BASED_POSTED_INTR;
+
+ if (!enable_vnmi)
+ pin_based_exec_ctrl &= ~PIN_BASED_VIRTUAL_NMIS;
+
/* Enable the preemption timer dynamically */
pin_based_exec_ctrl &= ~PIN_BASED_VMX_PREEMPTION_TIMER;
return pin_based_exec_ctrl;
@@ -5670,7 +5677,7 @@
static void enable_nmi_window(struct kvm_vcpu *vcpu)
{
- if (!cpu_has_virtual_nmis() ||
+ if (!enable_vnmi ||
vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_STI) {
enable_irq_window(vcpu);
return;
@@ -5711,7 +5718,7 @@
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
- if (!cpu_has_virtual_nmis()) {
+ if (!enable_vnmi) {
/*
* Tracking the NMI-blocked state in software is built upon
* finding the next open IRQ window. This, in turn, depends on
@@ -5742,7 +5749,7 @@
struct vcpu_vmx *vmx = to_vmx(vcpu);
bool masked;
- if (!cpu_has_virtual_nmis())
+ if (!enable_vnmi)
return vmx->loaded_vmcs->soft_vnmi_blocked;
if (vmx->loaded_vmcs->nmi_known_unmasked)
return false;
@@ -5755,7 +5762,7 @@
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
- if (!cpu_has_virtual_nmis()) {
+ if (!enable_vnmi) {
if (vmx->loaded_vmcs->soft_vnmi_blocked != masked) {
vmx->loaded_vmcs->soft_vnmi_blocked = masked;
vmx->loaded_vmcs->vnmi_blocked_time = 0;
@@ -5776,7 +5783,7 @@
if (to_vmx(vcpu)->nested.nested_run_pending)
return 0;
- if (!cpu_has_virtual_nmis() &&
+ if (!enable_vnmi &&
to_vmx(vcpu)->loaded_vmcs->soft_vnmi_blocked)
return 0;
@@ -6507,7 +6514,7 @@
* AAK134, BY25.
*/
if (!(to_vmx(vcpu)->idt_vectoring_info & VECTORING_INFO_VALID_MASK) &&
- cpu_has_virtual_nmis() &&
+ enable_vnmi &&
(exit_qualification & INTR_INFO_UNBLOCK_NMI))
vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, GUEST_INTR_STATE_NMI);
@@ -6567,6 +6574,7 @@
static int handle_nmi_window(struct kvm_vcpu *vcpu)
{
+ WARN_ON_ONCE(!enable_vnmi);
vmcs_clear_bits(CPU_BASED_VM_EXEC_CONTROL,
CPU_BASED_VIRTUAL_NMI_PENDING);
++vcpu->stat.nmi_window_exits;
@@ -6790,6 +6798,9 @@
if (!cpu_has_vmx_flexpriority())
flexpriority_enabled = 0;
+ if (!cpu_has_virtual_nmis())
+ enable_vnmi = 0;
+
/*
* set_apic_access_page_addr() is used to reload apic access
* page upon invalidation. No need to do anything if not
@@ -8011,7 +8022,7 @@
* "blocked by NMI" bit has to be set before next VM entry.
*/
if (!(to_vmx(vcpu)->idt_vectoring_info & VECTORING_INFO_VALID_MASK) &&
- cpu_has_virtual_nmis() &&
+ enable_vnmi &&
(exit_qualification & INTR_INFO_UNBLOCK_NMI))
vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO,
GUEST_INTR_STATE_NMI);
@@ -8856,7 +8867,7 @@
return 0;
}
- if (unlikely(!cpu_has_virtual_nmis() &&
+ if (unlikely(!enable_vnmi &&
vmx->loaded_vmcs->soft_vnmi_blocked)) {
if (vmx_interrupt_allowed(vcpu)) {
vmx->loaded_vmcs->soft_vnmi_blocked = 0;
@@ -9157,7 +9168,7 @@
idtv_info_valid = vmx->idt_vectoring_info & VECTORING_INFO_VALID_MASK;
- if (cpu_has_virtual_nmis()) {
+ if (enable_vnmi) {
if (vmx->loaded_vmcs->nmi_known_unmasked)
return;
/*
@@ -9306,7 +9317,7 @@
unsigned long debugctlmsr, cr3, cr4;
/* Record the guest's net vcpu time for enforced NMI injections. */
- if (unlikely(!cpu_has_virtual_nmis() &&
+ if (unlikely(!enable_vnmi &&
vmx->loaded_vmcs->soft_vnmi_blocked))
vmx->loaded_vmcs->entry_time = ktime_get();
