[Qemu-devel] [PATCH for-1.5 3/3] hw/pci-host/versatile.c: Provide property for forcing broken IRQ mapping

[Peter Maydell <peter.maydell@linaro.org>]

Although we try our best to automatically detect broken versions
of Linux which assume the old broken IRQ mapping we used to implement
for our model of the Versatile PCI controller, it turns out that
some particularly new kernels manage to outwit the autodetection.

We therefore provide a property for enabling the old broken IRQ
mapping, so that if users happen to have such a kernel they can
work around its deficiencies with the command line option:
  -global versatile_pci.broken-irq-mapping=1

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/pci-host/versatile.c |   14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/hw/pci-host/versatile.c b/hw/pci-host/versatile.c
index f19e2f5..2f996d9 100644
--- a/hw/pci-host/versatile.c
+++ b/hw/pci-host/versatile.c
@@ -54,6 +54,10 @@
  *   1      | 30 | 27 | 28 | 92
  *   2      | 27 | 27 | 29 | 93
  *   3      | 28 | 27 | 30 | 94
+ *
+ * Since our autodetection is not perfect we also provide a
+ * property so the user can make us start in BROKEN or FORCE_OK
+ * on reset if they know they have a bad or good kernel.
  */
 enum {
     PCI_VPB_IRQMAP_ASSUME_OK,
@@ -82,6 +86,7 @@ typedef struct {
     /* Constant for life of device: */
     int realview;
     uint32_t mem_win_size[3];
+    uint8_t irq_mapping_prop;
 
     /* Variable state: */
     uint32_t imap[3];
@@ -366,7 +371,7 @@ static void pci_vpb_reset(DeviceState *d)
     s->smap[2] = 0;
     s->selfid = 0;
     s->flags = 0;
-    s->irq_mapping = PCI_VPB_IRQMAP_ASSUME_OK;
+    s->irq_mapping = s->irq_mapping_prop;
 
     pci_vpb_update_all_windows(s);
 }
@@ -476,6 +481,12 @@ static const TypeInfo versatile_pci_host_info = {
     .class_init    = versatile_pci_host_class_init,
 };
 
+static Property pci_vpb_properties[] = {
+    DEFINE_PROP_UINT8("broken-irq-mapping", PCIVPBState, irq_mapping_prop,
+                      PCI_VPB_IRQMAP_ASSUME_OK),
+    DEFINE_PROP_END_OF_LIST()
+};
+
 static void pci_vpb_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
@@ -483,6 +494,7 @@ static void pci_vpb_class_init(ObjectClass *klass, void *data)
     dc->realize = pci_vpb_realize;
     dc->reset = pci_vpb_reset;
     dc->vmsd = &pci_vpb_vmstate;
+    dc->props = pci_vpb_properties;
 }
 
 static const TypeInfo pci_vpb_info = {
-- 
1.7.9.5