[Qemu-devel] [PATCH v2] kvm-irqchip: only commit route when irqchip is used

[Peter Xu <peterx@redhat.com>]

Reported from Alexey Kardashevskiy:

3f1fea0fb5bf "kvm-irqchip: do explicit commit when update irq" produces
a crash on pseries guest running with VFIO on POWER8 machine as it does
not support KVM_CAP_IRQCHIP (KVM_CAP_IRQ_XICS is there instead). At the
result, KVMState::irq_routes is NULL when VFIO calls
kvm_irqchip_commit_routes.

This makes the routing update conditional.

Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 kvm-all.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/kvm-all.c b/kvm-all.c
index ef81ca5..65608de 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1047,6 +1047,14 @@ void kvm_irqchip_commit_routes(KVMState *s)
 {
     int ret;
 
+    if (kvm_gsi_direct_mapping()) {
+        return;
+    }
+
+    if (!kvm_gsi_routing_enabled()) {
+        return;
+    }
+
     s->irq_routes->flags = 0;
     trace_kvm_irqchip_commit_routes();
     ret = kvm_vm_ioctl(s, KVM_SET_GSI_ROUTING, s->irq_routes);
-- 
2.7.4