[PATCH] KVM: VMX: require virtual NMI support
From: Paolo Bonzini
Date: Mon Mar 27 2017 - 08:38:41 EST
Virtual NMIs are only missing in Prescott and Yonah chips. Both are obsolete
for virtualization usage---Yonah is 32-bit only even---so drop vNMI emulation.
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 143 ++++++++++++++---------------------------------------
1 file changed, 38 insertions(+), 105 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 7f60c8deb379..b2f4bd731682 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -615,10 +615,6 @@ struct vcpu_vmx {
int vpid;
bool emulation_required;
- /* Support for vnmi-less CPUs */
- int soft_vnmi_blocked;
- ktime_t entry_time;
- s64 vnmi_blocked_time;
u32 exit_reason;
/* Posted interrupt descriptor */
@@ -1290,11 +1286,6 @@ static inline bool cpu_has_vmx_invpcid(void)
SECONDARY_EXEC_ENABLE_INVPCID;
}
-static inline bool cpu_has_virtual_nmis(void)
-{
- return vmcs_config.pin_based_exec_ctrl & PIN_BASED_VIRTUAL_NMIS;
-}
-
static inline bool cpu_has_vmx_wbinvd_exit(void)
{
return vmcs_config.cpu_based_2nd_exec_ctrl &
@@ -3623,9 +3614,9 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
&_vmexit_control) < 0)
return -EIO;
- min = PIN_BASED_EXT_INTR_MASK | PIN_BASED_NMI_EXITING;
- opt = PIN_BASED_VIRTUAL_NMIS | PIN_BASED_POSTED_INTR |
- PIN_BASED_VMX_PREEMPTION_TIMER;
+ min = PIN_BASED_EXT_INTR_MASK | PIN_BASED_NMI_EXITING |
+ PIN_BASED_VIRTUAL_NMIS;
+ opt = PIN_BASED_POSTED_INTR | PIN_BASED_VMX_PREEMPTION_TIMER;
if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_PINBASED_CTLS,
&_pin_based_exec_control) < 0)
return -EIO;
@@ -5298,8 +5289,6 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
vmx->rmode.vm86_active = 0;
- vmx->soft_vnmi_blocked = 0;
-
vmx->vcpu.arch.regs[VCPU_REGS_RDX] = get_rdx_init_val();
kvm_set_cr8(vcpu, 0);
@@ -5419,8 +5408,7 @@ static void enable_irq_window(struct kvm_vcpu *vcpu)
static void enable_nmi_window(struct kvm_vcpu *vcpu)
{
- if (!cpu_has_virtual_nmis() ||
- vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_STI) {
+ if (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_STI) {
enable_irq_window(vcpu);
return;
}
@@ -5461,19 +5449,6 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu)
struct vcpu_vmx *vmx = to_vmx(vcpu);
if (!is_guest_mode(vcpu)) {
- if (!cpu_has_virtual_nmis()) {
- /*
- * Tracking the NMI-blocked state in software is built upon
- * finding the next open IRQ window. This, in turn, depends on
- * well-behaving guests: They have to keep IRQs disabled at
- * least as long as the NMI handler runs. Otherwise we may
- * cause NMI nesting, maybe breaking the guest. But as this is
- * highly unlikely, we can live with the residual risk.
- */
- vmx->soft_vnmi_blocked = 1;
- vmx->vnmi_blocked_time = 0;
- }
-
++vcpu->stat.nmi_injections;
vmx->nmi_known_unmasked = false;
}
@@ -5490,8 +5465,6 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu)
static bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu)
{
- if (!cpu_has_virtual_nmis())
- return to_vmx(vcpu)->soft_vnmi_blocked;
if (to_vmx(vcpu)->nmi_known_unmasked)
return false;
return vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_NMI;
@@ -5501,20 +5474,13 @@ static void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
- if (!cpu_has_virtual_nmis()) {
- if (vmx->soft_vnmi_blocked != masked) {
- vmx->soft_vnmi_blocked = masked;
- vmx->vnmi_blocked_time = 0;
- }
- } else {
- vmx->nmi_known_unmasked = !masked;
- if (masked)
- vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO,
- GUEST_INTR_STATE_NMI);
- else
- vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
- GUEST_INTR_STATE_NMI);
- }
+ vmx->nmi_known_unmasked = !masked;
+ if (masked)
+ vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO,
+ GUEST_INTR_STATE_NMI);
+ else
+ vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
+ GUEST_INTR_STATE_NMI);
}
static int vmx_nmi_allowed(struct kvm_vcpu *vcpu)
@@ -5522,9 +5488,6 @@ static int vmx_nmi_allowed(struct kvm_vcpu *vcpu)
if (to_vmx(vcpu)->nested.nested_run_pending)
return 0;
- if (!cpu_has_virtual_nmis() && to_vmx(vcpu)->soft_vnmi_blocked)
- return 0;
-
return !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) &
(GUEST_INTR_STATE_MOV_SS | GUEST_INTR_STATE_STI
| GUEST_INTR_STATE_NMI));
@@ -6269,7 +6232,6 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu)
* AAK134, BY25.
*/
if (!(to_vmx(vcpu)->idt_vectoring_info & VECTORING_INFO_VALID_MASK) &&
- cpu_has_virtual_nmis() &&
(exit_qualification & INTR_INFO_UNBLOCK_NMI))
vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, GUEST_INTR_STATE_NMI);
@@ -7820,7 +7782,6 @@ static int handle_pml_full(struct kvm_vcpu *vcpu)
* "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() &&
(exit_qualification & INTR_INFO_UNBLOCK_NMI))
vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO,
GUEST_INTR_STATE_NMI);
@@ -8492,26 +8453,6 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu)
return 0;
}
- if (unlikely(!cpu_has_virtual_nmis() && vmx->soft_vnmi_blocked &&
- !(is_guest_mode(vcpu) && nested_cpu_has_virtual_nmis(
- get_vmcs12(vcpu))))) {
- if (vmx_interrupt_allowed(vcpu)) {
- vmx->soft_vnmi_blocked = 0;
- } else if (vmx->vnmi_blocked_time > 1000000000LL &&
- vcpu->arch.nmi_pending) {
- /*
- * This CPU don't support us in finding the end of an
- * NMI-blocked window if the guest runs with IRQs
- * disabled. So we pull the trigger after 1 s of
- * futile waiting, but inform the user about this.
- */
- printk(KERN_WARNING "%s: Breaking out of NMI-blocked "
- "state on VCPU %d after 1 s timeout\n",
- __func__, vcpu->vcpu_id);
- vmx->soft_vnmi_blocked = 0;
- }
- }
-
if (exit_reason < kvm_vmx_max_exit_handlers
&& kvm_vmx_exit_handlers[exit_reason])
return kvm_vmx_exit_handlers[exit_reason](vcpu);
@@ -8787,37 +8728,33 @@ static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx)
idtv_info_valid = vmx->idt_vectoring_info & VECTORING_INFO_VALID_MASK;
- if (cpu_has_virtual_nmis()) {
- if (vmx->nmi_known_unmasked)
- return;
- /*
- * Can't use vmx->exit_intr_info since we're not sure what
- * the exit reason is.
- */
- exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
- unblock_nmi = (exit_intr_info & INTR_INFO_UNBLOCK_NMI) != 0;
- vector = exit_intr_info & INTR_INFO_VECTOR_MASK;
- /*
- * SDM 3: 27.7.1.2 (September 2008)
- * Re-set bit "block by NMI" before VM entry if vmexit caused by
- * a guest IRET fault.
- * SDM 3: 23.2.2 (September 2008)
- * Bit 12 is undefined in any of the following cases:
- * If the VM exit sets the valid bit in the IDT-vectoring
- * information field.
- * If the VM exit is due to a double fault.
- */
- if ((exit_intr_info & INTR_INFO_VALID_MASK) && unblock_nmi &&
- vector != DF_VECTOR && !idtv_info_valid)
- vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO,
- GUEST_INTR_STATE_NMI);
- else
- vmx->nmi_known_unmasked =
- !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO)
- & GUEST_INTR_STATE_NMI);
- } else if (unlikely(vmx->soft_vnmi_blocked))
- vmx->vnmi_blocked_time +=
- ktime_to_ns(ktime_sub(ktime_get(), vmx->entry_time));
+ if (vmx->nmi_known_unmasked)
+ return;
+ /*
+ * Can't use vmx->exit_intr_info since we're not sure what
+ * the exit reason is.
+ */
+ exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
+ unblock_nmi = (exit_intr_info & INTR_INFO_UNBLOCK_NMI) != 0;
+ vector = exit_intr_info & INTR_INFO_VECTOR_MASK;
+ /*
+ * SDM 3: 27.7.1.2 (September 2008)
+ * Re-set bit "block by NMI" before VM entry if vmexit caused by
+ * a guest IRET fault.
+ * SDM 3: 23.2.2 (September 2008)
+ * Bit 12 is undefined in any of the following cases:
+ * If the VM exit sets the valid bit in the IDT-vectoring
+ * information field.
+ * If the VM exit is due to a double fault.
+ */
+ if ((exit_intr_info & INTR_INFO_VALID_MASK) && unblock_nmi &&
+ vector != DF_VECTOR && !idtv_info_valid)
+ vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO,
+ GUEST_INTR_STATE_NMI);
+ else
+ vmx->nmi_known_unmasked =
+ !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO)
+ & GUEST_INTR_STATE_NMI);
}
static void __vmx_complete_interrupts(struct kvm_vcpu *vcpu,
@@ -8934,10 +8871,6 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
struct vcpu_vmx *vmx = to_vmx(vcpu);
unsigned long debugctlmsr, cr4;
- /* Record the guest's net vcpu time for enforced NMI injections. */
- if (unlikely(!cpu_has_virtual_nmis() && vmx->soft_vnmi_blocked))
- vmx->entry_time = ktime_get();
-
/* Don't enter VMX if guest state is invalid, let the exit handler
start emulation until we arrive back to a valid state */
if (vmx->emulation_required)
--
1.8.3.1