KVM: x86: Support for user space injected NMIs
Introduces the KVM_NMI IOCTL to the generic x86 part of KVM for
injecting NMIs from user space and also extends the statistic report
accordingly.
Based on the original patch by Sheng Yang.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1fa9a6d..0797145 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -86,6 +86,7 @@
{ "halt_wakeup", VCPU_STAT(halt_wakeup) },
{ "hypercalls", VCPU_STAT(hypercalls) },
{ "request_irq", VCPU_STAT(request_irq_exits) },
+ { "request_nmi", VCPU_STAT(request_nmi_exits) },
{ "irq_exits", VCPU_STAT(irq_exits) },
{ "host_state_reload", VCPU_STAT(host_state_reload) },
{ "efer_reload", VCPU_STAT(efer_reload) },
@@ -93,6 +94,7 @@
{ "insn_emulation", VCPU_STAT(insn_emulation) },
{ "insn_emulation_fail", VCPU_STAT(insn_emulation_fail) },
{ "irq_injections", VCPU_STAT(irq_injections) },
+ { "nmi_injections", VCPU_STAT(nmi_injections) },
{ "mmu_shadow_zapped", VM_STAT(mmu_shadow_zapped) },
{ "mmu_pte_write", VM_STAT(mmu_pte_write) },
{ "mmu_pte_updated", VM_STAT(mmu_pte_updated) },
@@ -1318,6 +1320,15 @@
return 0;
}
+static int kvm_vcpu_ioctl_nmi(struct kvm_vcpu *vcpu)
+{
+ vcpu_load(vcpu);
+ kvm_inject_nmi(vcpu);
+ vcpu_put(vcpu);
+
+ return 0;
+}
+
static int vcpu_ioctl_tpr_access_reporting(struct kvm_vcpu *vcpu,
struct kvm_tpr_access_ctl *tac)
{
@@ -1377,6 +1388,13 @@
r = 0;
break;
}
+ case KVM_NMI: {
+ r = kvm_vcpu_ioctl_nmi(vcpu);
+ if (r)
+ goto out;
+ r = 0;
+ break;
+ }
case KVM_SET_CPUID: {
struct kvm_cpuid __user *cpuid_arg = argp;
struct kvm_cpuid cpuid;
@@ -2812,18 +2830,37 @@
(kvm_x86_ops->get_rflags(vcpu) & X86_EFLAGS_IF));
}
+/*
+ * Check if userspace requested a NMI window, and that the NMI window
+ * is open.
+ *
+ * No need to exit to userspace if we already have a NMI queued.
+ */
+static int dm_request_for_nmi_injection(struct kvm_vcpu *vcpu,
+ struct kvm_run *kvm_run)
+{
+ return (!vcpu->arch.nmi_pending &&
+ kvm_run->request_nmi_window &&
+ vcpu->arch.nmi_window_open);
+}
+
static void post_kvm_run_save(struct kvm_vcpu *vcpu,
struct kvm_run *kvm_run)
{
kvm_run->if_flag = (kvm_x86_ops->get_rflags(vcpu) & X86_EFLAGS_IF) != 0;
kvm_run->cr8 = kvm_get_cr8(vcpu);
kvm_run->apic_base = kvm_get_apic_base(vcpu);
- if (irqchip_in_kernel(vcpu->kvm))
+ if (irqchip_in_kernel(vcpu->kvm)) {
kvm_run->ready_for_interrupt_injection = 1;
- else
+ kvm_run->ready_for_nmi_injection = 1;
+ } else {
kvm_run->ready_for_interrupt_injection =
(vcpu->arch.interrupt_window_open &&
vcpu->arch.irq_summary == 0);
+ kvm_run->ready_for_nmi_injection =
+ (vcpu->arch.nmi_window_open &&
+ vcpu->arch.nmi_pending == 0);
+ }
}
static void vapic_enter(struct kvm_vcpu *vcpu)
@@ -2999,6 +3036,11 @@
}
if (r > 0) {
+ if (dm_request_for_nmi_injection(vcpu, kvm_run)) {
+ r = -EINTR;
+ kvm_run->exit_reason = KVM_EXIT_NMI;
+ ++vcpu->stat.request_nmi_exits;
+ }
if (dm_request_for_irq_injection(vcpu, kvm_run)) {
r = -EINTR;
kvm_run->exit_reason = KVM_EXIT_INTR;