[PATCH 38/42] KVM: SVM: Notify nested hypervisor of lost event injections

Avi Kivity
2009-11-16T12:20:35Z

From: Alexander Graf <agraf@suse.de>

If event_inj is valid on a #vmexit the host CPU would write
the contents to exit_int_info, so the hypervisor knows that
the event wasn't injected.

We don't do this in nested SVM by now which is a bug and
fixed by this patch.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
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 279a2ae..e372854 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1615,6 +1615,22 @@ 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 case
+ * below only happens on a VMRUN instruction intercept which has
+ * no 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;
--
1.6.5.2