[PATCH 03/67] KVM: x86: Explicitly treat routing entry type changes as changes

From: Sean Christopherson
Date: Fri Apr 04 2025 - 15:40:53 EST


Explicitly treat type differences as GSI routing changes, as comparing MSI
data between two entries could get a false negative, e.g. if userspace
changed the type but left the type-specific data as-is.

Fixes: 515a0c79e796 ("kvm: irqfd: avoid update unmodified entries of the routing")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9211344b20ae..f94f1217a087 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -13615,7 +13615,8 @@ int kvm_arch_update_irqfd_routing(struct kvm *kvm, unsigned int host_irq,
bool kvm_arch_irqfd_route_changed(struct kvm_kernel_irq_routing_entry *old,
struct kvm_kernel_irq_routing_entry *new)
{
- if (new->type != KVM_IRQ_ROUTING_MSI)
+ if (old->type != KVM_IRQ_ROUTING_MSI ||
+ new->type != KVM_IRQ_ROUTING_MSI)
return true;

return !!memcmp(&old->msi, &new->msi, sizeof(new->msi));
--
2.49.0.504.g3bcea36a83-goog