From: Sean Christopherson Date: Wed, 11 Jun 2025 22:45:39 +0000 (-0700) Subject: KVM: x86: Don't update IRTE entries when old and new routes were !MSI X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cc8b13105eac969bb721c52cf95fd35818b5c54c;p=thirdparty%2Fkernel%2Fstable.git KVM: x86: Don't update IRTE entries when old and new routes were !MSI 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. Link: https://lore.kernel.org/r/20250611224604.313496-38-seanjc@google.com Signed-off-by: Sean Christopherson --- diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c index ecebd150c2f7..bc9ebd893566 100644 --- a/arch/x86/kvm/irq.c +++ b/arch/x86/kvm/irq.c @@ -618,6 +618,10 @@ 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)))