kvm: x86: Establish IRQ0 override control

KVM is forced to disable the IRQ0 override when we run with in-kernel
irqchip but without IRQ routing support of the kernel. Set the fwcfg
value correspondingly. This aligns us with qemu-kvm.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/kvm-all.c b/kvm-all.c
index fa9d92d005..88f11567f7 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1307,6 +1307,11 @@ int kvm_has_gsi_routing(void)
     return kvm_check_extension(kvm_state, KVM_CAP_IRQ_ROUTING);
 }
 
+int kvm_allows_irq0_override(void)
+{
+    return !kvm_enabled() || !kvm_irqchip_in_kernel() || kvm_has_gsi_routing();
+}
+
 void kvm_setup_guest_memory(void *start, size_t size)
 {
     if (!kvm_has_sync_mmu()) {