KVM: arm/arm64: Enable MSI routing

Up to now, only irqchip routing entries could be set. This patch
adds the capability to insert MSI routing entries.

For ARM64, let's also increase KVM_MAX_IRQ_ROUTES to 4096: this
include SPI irqchip routes plus MSI routes. In the future this
might be extended.
Signed-off-by: NEric Auger <eric.auger@redhat.com>
Reviewed-by: NAndre Przywara <andre.przywara@arm.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Documentation/virtual/kvm/api.txt

@@ -2381,6 +2381,9 @@ On arm/arm64, gsi routing being supported, the following can happen:
 - in case no routing entry is associated to this gsi, injection fails
 - in case the gsi is associated to an irqchip routing entry,
   irqchip.pin + 32 corresponds to the injected SPI ID.
+- in case the gsi is associated to an MSI routing entry, the MSI
+  message and device ID are translated into an LPI (support restricted
+  to GICv3 ITS in-kernel emulation).
 
 4.76 KVM_PPC_ALLOCATE_HTAB
 

include/linux/kvm_host.h

@@ -1048,6 +1048,8 @@ static inline int mmu_notifier_retry(struct kvm *kvm, unsigned long mmu_seq)
 
 #ifdef CONFIG_S390
 #define KVM_MAX_IRQ_ROUTES 4096 //FIXME: we can have more than that...
+#elif defined(CONFIG_ARM64)
+#define KVM_MAX_IRQ_ROUTES 4096
 #else
 #define KVM_MAX_IRQ_ROUTES 1024
 #endif

virt/kvm/arm/vgic/vgic-irqfd.c

@@ -59,6 +59,14 @@ int kvm_set_routing_entry(struct kvm_kernel_irq_routing_entry *e,
 		    (e->irqchip.irqchip >= KVM_NR_IRQCHIPS))
 			goto out;
 		break;
+	case KVM_IRQ_ROUTING_MSI:
+		e->set = kvm_set_msi;
+		e->msi.address_lo = ue->u.msi.address_lo;
+		e->msi.address_hi = ue->u.msi.address_hi;
+		e->msi.data = ue->u.msi.data;
+		e->msi.flags = ue->flags;
+		e->msi.devid = ue->u.msi.devid;
+		break;
 	default:
 		goto out;
 	}

virt/kvm/irqchip.c

@@ -178,6 +178,7 @@ int kvm_set_irq_routing(struct kvm *kvm,
 			unsigned flags)
 {
 	struct kvm_irq_routing_table *new, *old;
+	struct kvm_kernel_irq_routing_entry *e;
 	u32 i, j, nr_rt_entries = 0;
 	int r;
 
@@ -201,23 +202,25 @@ int kvm_set_irq_routing(struct kvm *kvm,
 			new->chip[i][j] = -1;
 
 	for (i = 0; i < nr; ++i) {
-		struct kvm_kernel_irq_routing_entry *e;
-
 		r = -ENOMEM;
 		e = kzalloc(sizeof(*e), GFP_KERNEL);
 		if (!e)
 			goto out;
 
 		r = -EINVAL;
-		if (ue->flags) {
-			kfree(e);
-			goto out;
+		switch (ue->type) {
+		case KVM_IRQ_ROUTING_MSI:
+			if (ue->flags & ~KVM_MSI_VALID_DEVID)
+				goto free_entry;
+			break;
+		default:
+			if (ue->flags)
+				goto free_entry;
+			break;
 		}
 		r = setup_routing_entry(new, e, ue);
-		if (r) {
-			kfree(e);
-			goto out;
-		}
+		if (r)
+			goto free_entry;
 		++ue;
 	}
 
@@ -234,7 +237,10 @@ int kvm_set_irq_routing(struct kvm *kvm,
 
 	new = old;
 	r = 0;
+	goto out;
 
+free_entry:
+	kfree(e);
 out:
 	free_irq_routing_table(new);