KVM: x86: Add KVM_GET/SET_VCPU_EVENTS

This new IOCTL exports all yet user-invisible states related to
exceptions, interrupts, and NMIs. Together with appropriate user space
changes, this fixes sporadic problems of vmsave/restore, live migration
and system reset.

[avi: future-proof abi by adding a flags field]

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 22fcd27a0b58..778f059ae423 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2639,6 +2639,34 @@ static int vmx_nmi_allowed(struct kvm_vcpu *vcpu)
                                 GUEST_INTR_STATE_NMI));
 }
 
+static bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu)
+{
+        if (!cpu_has_virtual_nmis())
+                return to_vmx(vcpu)->soft_vnmi_blocked;
+        else
+                return !!(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) &
+                          GUEST_INTR_STATE_NMI);
+}
+
+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 {
+                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_interrupt_allowed(struct kvm_vcpu *vcpu)
 {
         return (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) &&
@@ -3985,6 +4013,8 @@ static struct kvm_x86_ops vmx_x86_ops = {
         .queue_exception = vmx_queue_exception,
         .interrupt_allowed = vmx_interrupt_allowed,
         .nmi_allowed = vmx_nmi_allowed,
+        .get_nmi_mask = vmx_get_nmi_mask,
+        .set_nmi_mask = vmx_set_nmi_mask,
         .enable_nmi_window = enable_nmi_window,
         .enable_irq_window = enable_irq_window,
         .update_cr8_intercept = update_cr8_intercept,