[PULL,1/3] -machine vmport=auto: Fix handling of VMWare ioport emulation for xen

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 8be50a4..f31d55e 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -61,6 +61,7 @@ 
 #include "hw/mem/pc-dimm.h"
 #include "trace.h"
 #include "qapi/visitor.h"
+#include "qapi-visit.h"
 
 /* debug PC/ISA interrupts */
 //#define DEBUG_IRQ
@@ -1772,18 +1773,21 @@  static void pc_machine_set_max_ram_below_4g(Object *obj, Visitor *v,
     pcms->max_ram_below_4g = value;
 }
 
-static bool pc_machine_get_vmport(Object *obj, Error **errp)
+static void pc_machine_get_vmport(Object *obj, Visitor *v, void *opaque,
+                                  const char *name, Error **errp)
 {
     PCMachineState *pcms = PC_MACHINE(obj);
+    OnOffAuto vmport = pcms->vmport;
 
-    return pcms->vmport;
+    visit_type_OnOffAuto(v, &vmport, name, errp);
 }
 
-static void pc_machine_set_vmport(Object *obj, bool value, Error **errp)
+static void pc_machine_set_vmport(Object *obj, Visitor *v, void *opaque,
+                                  const char *name, Error **errp)
 {
     PCMachineState *pcms = PC_MACHINE(obj);
 
-    pcms->vmport = value;
+    visit_type_OnOffAuto(v, &pcms->vmport, name, errp);
 }
 
 static bool pc_machine_get_aligned_dimm(Object *obj, Error **errp)
@@ -1806,11 +1810,11 @@  static void pc_machine_initfn(Object *obj)
                         pc_machine_set_max_ram_below_4g,
                         NULL, NULL, NULL);
 
-    pcms->vmport = !xen_enabled();
-    object_property_add_bool(obj, PC_MACHINE_VMPORT,
-                             pc_machine_get_vmport,
-                             pc_machine_set_vmport,
-                             NULL);
+    pcms->vmport = ON_OFF_AUTO_AUTO;
+    object_property_add(obj, PC_MACHINE_VMPORT, "OnOffAuto",
+                        pc_machine_get_vmport,
+                        pc_machine_set_vmport,
+                        NULL, NULL, NULL);
 
     pcms->enforce_aligned_dimm = true;
     object_property_add_bool(obj, PC_MACHINE_ENFORCE_ALIGNED_DIMM,
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 741dffd..85ed3c8 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -234,9 +234,14 @@  static void pc_init1(MachineState *machine,
 
     pc_vga_init(isa_bus, pci_enabled ? pci_bus : NULL);
 
+    assert(pc_machine->vmport != ON_OFF_AUTO_MAX);
+    if (pc_machine->vmport == ON_OFF_AUTO_AUTO) {
+        pc_machine->vmport = xen_enabled() ? ON_OFF_AUTO_OFF : ON_OFF_AUTO_ON;
+    }
+
     /* init basic PC hardware */
     pc_basic_device_init(isa_bus, gsi, &rtc_state, &floppy,
-                         !pc_machine->vmport, 0x4);
+                         (pc_machine->vmport != ON_OFF_AUTO_ON), 0x4);
 
     pc_nic_init(isa_bus, pci_bus);
 
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index e9ba1a2..0262b5e 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -242,9 +242,14 @@  static void pc_q35_init(MachineState *machine)
 
     pc_register_ferr_irq(gsi[13]);
 
+    assert(pc_machine->vmport != ON_OFF_AUTO_MAX);
+    if (pc_machine->vmport == ON_OFF_AUTO_AUTO) {
+        pc_machine->vmport = xen_enabled() ? ON_OFF_AUTO_OFF : ON_OFF_AUTO_ON;
+    }
+
     /* init basic PC hardware */
     pc_basic_device_init(isa_bus, gsi, &rtc_state, &floppy,
-                         !pc_machine->vmport, 0xff0104);
+                         (pc_machine->vmport != ON_OFF_AUTO_ON), 0xff0104);
 
     /* connect pm stuff to lpc */
     ich9_lpc_pm_init(lpc);
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 9d85b89..69d9cf8 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -39,7 +39,7 @@  struct PCMachineState {
     ISADevice *rtc;
 
     uint64_t max_ram_below_4g;
-    bool vmport;
+    OnOffAuto vmport;
     bool enforce_aligned_dimm;
 };
 
diff --git a/qapi/common.json b/qapi/common.json
index 4e9a21f..63ef3b4 100644
--- a/qapi/common.json
+++ b/qapi/common.json
@@ -87,3 +87,18 @@ 
 ##
 { 'command': 'query-commands', 'returns': ['CommandInfo'] }
 
+##
+# @OnOffAuto
+#
+# An enumeration of three options: on, off, and auto
+#
+# @auto: QEMU selects the value between on and off
+#
+# @on: Enabled
+#
+# @off: Disabled
+#
+# Since: 2.2
+##
+{ 'enum': 'OnOffAuto',
+  'data': [ 'auto', 'on', 'off' ] }
diff --git a/qemu-options.hx b/qemu-options.hx
index da9851d..64af16d 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -33,7 +33,7 @@  DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
     "                property accel=accel1[:accel2[:...]] selects accelerator\n"
     "                supported accelerators are kvm, xen, tcg (default: tcg)\n"
     "                kernel_irqchip=on|off controls accelerated irqchip support\n"
-    "                vmport=on|off controls emulation of vmport (default: on)\n"
+    "                vmport=on|off|auto controls emulation of vmport (default: auto)\n"
     "                kvm_shadow_mem=size of KVM shadow MMU\n"
     "                dump-guest-core=on|off include guest memory in a core dump (default=on)\n"
     "                mem-merge=on|off controls memory merge support (default: on)\n"
@@ -52,8 +52,10 @@  than one accelerator specified, the next one is used if the previous one fails
 to initialize.
 @item kernel_irqchip=on|off
 Enables in-kernel irqchip support for the chosen accelerator when available.
-@item vmport=on|off
-Enables emulation of VMWare IO port, for vmmouse etc. (enabled by default)
+@item vmport=on|off|auto
+Enables emulation of VMWare IO port, for vmmouse etc. auto says to select the
+value based on accel. For accel=xen the default is off otherwise the default
+is on.
 @item kvm_shadow_mem=size
 Defines the size of the KVM shadow MMU.
 @item dump-guest-core=on|off
diff --git a/vl.c b/vl.c
index f4a6e5e..eb89d62 100644
--- a/vl.c
+++ b/vl.c
@@ -381,7 +381,7 @@  static QemuOptsList qemu_machine_opts = {
             .help = "maximum ram below the 4G boundary (32bit boundary)",
         }, {
             .name = PC_MACHINE_VMPORT,
-            .type = QEMU_OPT_BOOL,
+            .type = QEMU_OPT_STRING,
             .help = "Enable vmport (pc & q35)",
         },{
             .name = "iommu",