[Qemu-devel] [PATCH 48/81] x86: ioapic: fix fail migration when irqchip=split

[Michael Roth]

From: Peter Xu <address@hidden>

Split irqchip works based on the fact that we kept the first 24 gsi
routing entries inside KVM for userspace ioapic's use. When system
boot, we'll reserve these MSI routing entries before hand. However,
after migration, we forgot to re-configure it up in the destination
side. The result is, we'll get invalid gsi routing entries after
migration (all empty), and we get interrupts with vector=0, then
strange things happen, like keyboard hang.

The solution is simple - we update them after migration, which is a
one line fix.

Signed-off-by: Peter Xu <address@hidden>
Message-Id: <address@hidden>
Cc: address@hidden
Signed-off-by: Paolo Bonzini <address@hidden>
(cherry picked from commit 0f254b1ae04b36e2ab2d91528297ed60d40c8c08)
Signed-off-by: Michael Roth <address@hidden>
---
 hw/intc/ioapic.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/intc/ioapic.c b/hw/intc/ioapic.c
index fd9208f..5fa8481 100644
--- a/hw/intc/ioapic.c
+++ b/hw/intc/ioapic.c
@@ -426,6 +426,11 @@ static void ioapic_class_init(ObjectClass *klass, void 
*data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     k->realize = ioapic_realize;
+    /*
+     * If APIC is in kernel, we need to update the kernel cache after
+     * migration, otherwise first 24 gsi routes will be invalid.
+     */
+    k->post_load = ioapic_update_kvm_routes;
     dc->reset = ioapic_reset_common;
     dc->props = ioapic_properties;
 }
-- 
2.7.4