KVM: x86: Do not return soft events in vcpu_events

To avoid that user space migrates a pending software exception or
interrupt, mask them out on KVM_GET_VCPU_EVENTS. Without this, user
space would try to reinject them, and we would have to reconstruct the
proper instruction length for VMX event injection. Now the pending event
will be reinjected via executing the triggering instruction again.

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

1 files changed, 6 insertions, 3 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1d27a57026a..2b1c9f2fb8d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2100,14 +2100,17 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu,
 {
         vcpu_load(vcpu);
 
-        events->exception.injected = vcpu->arch.exception.pending;
+        events->exception.injected =
+                vcpu->arch.exception.pending &&
+                !kvm_exception_is_soft(vcpu->arch.exception.nr);
         events->exception.nr = vcpu->arch.exception.nr;
         events->exception.has_error_code = vcpu->arch.exception.has_error_code;
         events->exception.error_code = vcpu->arch.exception.error_code;
 
-        events->interrupt.injected = vcpu->arch.interrupt.pending;
+        events->interrupt.injected =
+                vcpu->arch.interrupt.pending && !vcpu->arch.interrupt.soft;
         events->interrupt.nr = vcpu->arch.interrupt.nr;
-        events->interrupt.soft = vcpu->arch.interrupt.soft;
+        events->interrupt.soft = 0;
 
         events->nmi.injected = vcpu->arch.nmi_injected;
         events->nmi.pending = vcpu->arch.nmi_pending;