[PATCH 5/5] Notify nested hypervisor of lost event injections

[Alexander Graf <agraf@suse.de>]

Normally when event_inj is valid the host CPU would write the contents to
exit_int_info, so the hypervisor knows that the event wasn't injected.

We failed to do so so far, so let's model closer to the CPU.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 arch/x86/kvm/svm.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 12ec8ee..75e3d75 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1643,6 +1643,22 @@ static int nested_svm_vmexit(struct vcpu_svm *svm)
 	nested_vmcb->control.exit_info_2       = vmcb->control.exit_info_2;
 	nested_vmcb->control.exit_int_info     = vmcb->control.exit_int_info;
 	nested_vmcb->control.exit_int_info_err = vmcb->control.exit_int_info_err;
+
+	/*
+	 * If we emulate a VMRUN/#VMEXIT in the same host #vmexit cycle we have
+	 * to make sure that we do not lose injected events. So check event_inj
+	 * here and copy it to exit_int_info if it is valid.
+	 * exit_int_info and event_inj can't be both valid because the below
+	 * case only happens on a VMRUN instruction intercept which has not
+	 * valid exit_int_info set.
+	 */
+	if (vmcb->control.event_inj & SVM_EVTINJ_VALID) {
+		struct vmcb_control_area *nc = &nested_vmcb->control;
+
+		nc->exit_int_info     = vmcb->control.event_inj;
+		nc->exit_int_info_err = vmcb->control.event_inj_err;
+	}
+
 	nested_vmcb->control.tlb_ctl           = 0;
 	nested_vmcb->control.event_inj         = 0;
 	nested_vmcb->control.event_inj_err     = 0;
-- 
1.6.0.2