[PATCH v3 5/9] KVM: SVM: Populate FRED event data on event injection

[Shivansh Dhiman]

From: Neeraj Upadhyay <Neeraj.Upadhyay@xxxxxxx>

Set injected-event data (in EVENTINJDATA) when injecting an event,
use EXITINTDATA for populating the injected-event data during
reinjection.

Unlike IDT using some extra CPU register as part of an event
context, e.g., %cr2 for #PF, FRED saves a complete event context
in its stack frame, e.g., FRED saves the faulting linear address
of a #PF into the event data field defined in its stack frame.

Populate the EVENTINJDATA during event injection. The event data
will be pushed into a FRED stack frame for VM entries that inject
an event using FRED event delivery.

Signed-off-by: Neeraj Upadhyay <Neeraj.Upadhyay@xxxxxxx>
Co-developed-by: Shivansh Dhiman <shivansh.dhiman@xxxxxxx>
Signed-off-by: Shivansh Dhiman <shivansh.dhiman@xxxxxxx>
---

Changes in v3:
* Rebased, no changes.

Changes in v2:
* Removed the need for a new function parameter 'reinject_on_vmexit' in
  svm_complete_interrupts() (Paolo Bonzini).

---
 arch/x86/kvm/svm/svm.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 72d49c6daee7..6c15e8480d25 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -401,6 +401,10 @@ static void svm_inject_exception(struct kvm_vcpu *vcpu)
 		| SVM_EVTINJ_VALID
 		| (ex->has_error_code ? SVM_EVTINJ_VALID_ERR : 0)
 		| SVM_EVTINJ_TYPE_EXEPT;
+
+	if (is_fred_enabled(vcpu))
+		svm->vmcb->control.event_inj_data = ex->event_data;
+
 	svm->vmcb->control.event_inj_err = ex->error_code;
 }
 
@@ -4478,6 +4482,7 @@ static void svm_complete_interrupts(struct kvm_vcpu *vcpu)
 		break;
 	case SVM_EXITINTINFO_TYPE_EXEPT: {
 		u32 error_code = 0;
+		u64 event_data = 0;
 
 		/*
 		 * Never re-inject a #VC exception.
@@ -4488,9 +4493,16 @@ static void svm_complete_interrupts(struct kvm_vcpu *vcpu)
 		if (exitintinfo & SVM_EXITINTINFO_VALID_ERR)
 			error_code = svm->vmcb->control.exit_int_info_err;
 
+		/*
+		 * FRED requires an additional field to pass injected-event
+		 * data to the guest.
+		 */
+		if (is_fred_enabled(vcpu) && (vector == PF_VECTOR || vector == DB_VECTOR))
+			event_data = svm->vmcb->control.exit_int_data;
+
 		kvm_requeue_exception(vcpu, vector,
 				      exitintinfo & SVM_EXITINTINFO_VALID_ERR,
-				      error_code, false, 0);
+				      error_code, false, event_data);
 		break;
 	}
 	case SVM_EXITINTINFO_TYPE_INTR:
@@ -4512,6 +4524,7 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu)
 
 	control->exit_int_info = control->event_inj;
 	control->exit_int_info_err = control->event_inj_err;
+	control->exit_int_data = control->event_inj_data;
 	control->event_inj = 0;
 	svm_complete_interrupts(vcpu);
 }
-- 
2.43.0