KVM: x86: Allow marking an exception as reinjected

This patch adds logic to kvm/x86 which allows to mark an
injected exception as reinjected. This allows to remove an
ugly hack from svm_complete_interrupts that prevented
exceptions from being reinjected at all in the nested case.
The hack was necessary because an reinjected exception into
the nested guest could cause a nested vmexit emulation. But
reinjected exceptions must not intercept. The downside of
the hack is that a exception that in injected could get
lost.
This patch fixes the problem and puts the code for it into
generic x86 files because. Nested-VMX will likely have the
same problem and could reuse the code.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 65fc11438b75..30e49fe7f8c0 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -338,7 +338,8 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
 }
 
 static void svm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
-				bool has_error_code, u32 error_code)
+				bool has_error_code, u32 error_code,
+				bool reinject)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 
@@ -346,7 +347,8 @@ static void svm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
 	 * If we are within a nested VM we'd better #VMEXIT and let the guest
 	 * handle the exception
 	 */
-	if (nested_svm_check_exception(svm, nr, has_error_code, error_code))
+	if (!reinject &&
+	    nested_svm_check_exception(svm, nr, has_error_code, error_code))
 		return;
 
 	if (nr == BP_VECTOR && !svm_has(SVM_FEATURE_NRIP)) {
@@ -2918,8 +2920,6 @@ static void svm_complete_interrupts(struct vcpu_svm *svm)
 		svm->vcpu.arch.nmi_injected = true;
 		break;
 	case SVM_EXITINTINFO_TYPE_EXEPT:
-		if (is_nested(svm))
-			break;
 		/*
 		 * In case of software exceptions, do not reinject the vector,
 		 * but re-execute the instruction instead. Rewind RIP first
@@ -2935,10 +2935,10 @@ static void svm_complete_interrupts(struct vcpu_svm *svm)
 		}
 		if (exitintinfo & SVM_EXITINTINFO_VALID_ERR) {
 			u32 err = svm->vmcb->control.exit_int_info_err;
-			kvm_queue_exception_e(&svm->vcpu, vector, err);
+			kvm_requeue_exception_e(&svm->vcpu, vector, err);
 
 		} else
-			kvm_queue_exception(&svm->vcpu, vector);
+			kvm_requeue_exception(&svm->vcpu, vector);
 		break;
 	case SVM_EXITINTINFO_TYPE_INTR:
 		kvm_queue_interrupt(&svm->vcpu, vector, false);