[RFC 30/55] KVM: arm/arm64: Inject irqs to the guest hypervisor

[Jintack Lim]

If we have a pending IRQ for the guest and the guest expects IRQs
to be handled in its virtual EL2 mode (the virtual IMO bit is set)
and it is not already running in virtual EL2 mode, then we have to
emulate an IRQ exception.

Signed-off-by: Jintack Lim <jintack@xxxxxxxxxxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
---
 virt/kvm/arm/vgic/vgic.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index 6440b56..4a98654 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -17,6 +17,7 @@
 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
 #include <linux/list_sort.h>
+#include <asm/kvm_emulate.h>
 
 #include "vgic.h"
 
@@ -652,6 +653,28 @@ static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)
 	/* Nuke remaining LRs */
 	for ( ; count < kvm_vgic_global_state.nr_lr; count++)
 		vgic_clear_lr(vcpu, count);
+
+	/*
+	 * If we have any pending IRQ for the guest and the guest expects IRQs
+	 * to be handled in its virtual EL2 mode (the virtual IMO bit is set)
+	 * and it is not already running in virtual EL2 mode, then we have to
+	 * emulate an IRQ exception to virtual IRQ. Note that a pending IRQ
+	 * means an irq of which state is pending but not active.
+	 */
+	if (vcpu_el2_imo_is_set(vcpu) && !vcpu_mode_el2(vcpu)) {
+		bool pending = false;
+
+		list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
+			spin_lock(&irq->irq_lock);
+			pending = irq->pending && irq->enabled && !irq->active;
+			spin_unlock(&irq->irq_lock);
+
+			if (pending) {
+				kvm_inject_nested_irq(vcpu);
+				break;
+			}
+		}
+	}
 }
 
 /* Sync back the hardware VGIC state into our emulation after a guest's run. */
-- 
1.9.1