[PATCH 41/67] KVM: x86: Don't update IRTE entries when old and new routes were !MSI

[Sean Christopherson]

Skip the entirety of IRTE updates on a GSI routing change if neither the
old nor the new routing is for an MSI, i.e. if the neither routing setup
allows for posting to a vCPU.  If the IRTE isn't already host controlled,
KVM has bigger problems.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 arch/x86/kvm/x86.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8325a908fa25..0dc3b45cb664 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -13678,6 +13678,10 @@ void kvm_arch_update_irqfd_routing(struct kvm_kernel_irqfd *irqfd,
 				   struct kvm_kernel_irq_routing_entry *old,
 				   struct kvm_kernel_irq_routing_entry *new)
 {
+	if (new->type != KVM_IRQ_ROUTING_MSI &&
+	    old->type != KVM_IRQ_ROUTING_MSI)
+		return;
+
 	if (old->type == KVM_IRQ_ROUTING_MSI &&
 	    new->type == KVM_IRQ_ROUTING_MSI &&
 	    !memcmp(&old->msi, &new->msi, sizeof(new->msi)))
-- 
2.49.0.504.g3bcea36a83-goog