vmxnet3: Introduce 'x-disable-pcie' back-compat property

Following the previous patch which changed vmxnet3 to be a pci express
device, this patch introduces a boolean property 'x-disable-pcie' whose
default is false.

Setting 'x-disable-pcie' to 'on' preserves the old 'pci device' (non
express) behavior. This allows migration to older versions.

Signed-off-by: Shmulik Ladkani <shmulik.ladkani@ravellosystems.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

hw/net/vmxnet3.c

@@ -2663,6 +2663,8 @@ static Property vmxnet3_properties[] = {
     DEFINE_NIC_PROPERTIES(VMXNET3State, conf),
     DEFINE_PROP_BIT("x-old-msi-offsets", VMXNET3State, compat_flags,
                     VMXNET3_COMPAT_FLAG_OLD_MSI_OFFSETS_BIT, false),
+    DEFINE_PROP_BIT("x-disable-pcie", VMXNET3State, compat_flags,
+                    VMXNET3_COMPAT_FLAG_DISABLE_PCIE_BIT, false),
     DEFINE_PROP_END_OF_LIST(),
 };
 

include/hw/compat.h

@@ -6,6 +6,10 @@
         .driver   = "vmxnet3",\
         .property = "x-old-msi-offsets",\
         .value    = "on",\
+    },{\
+        .driver   = "vmxnet3",\
+        .property = "x-disable-pcie",\
+        .value    = "on",\
     },
 
 #define HW_COMPAT_2_4 \