[PATCH 6/6 v7] allow the user to disable pv event support

[Wen Congyang <wency@cn.fujitsu.com>]

The qom device uses a fixed PIO port that might conflict
with (non-Linux) guest expectations and/or future device models.
So allow the user to disable it.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 hw/pc_piix.c    |    6 +++++-
 qemu-config.c   |    4 ++++
 qemu-options.hx |    3 ++-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/hw/pc_piix.c b/hw/pc_piix.c
index 7ec2853..48fae72 100644
--- a/hw/pc_piix.c
+++ b/hw/pc_piix.c
@@ -151,6 +151,8 @@ static void pc_init1(MemoryRegion *system_memory,
     MemoryRegion *pci_memory;
     MemoryRegion *rom_memory;
     void *fw_cfg = NULL;
+    QemuOptsList *list = qemu_find_opts("machine");
+    bool enable_pv_event;
 
     pc_cpus_init(cpu_model);
 
@@ -289,8 +291,10 @@ static void pc_init1(MemoryRegion *system_memory,
         pc_pci_device_init(pci_bus);
     }
 
+    enable_pv_event = qemu_opt_get_bool(QTAILQ_FIRST(&list->head),
+                                        "enable_pv_event", false);
 #ifdef KVM_PV_PORT
-    if (kvm_enabled()) {
+    if (kvm_enabled() && enable_pv_event) {
         kvm_pv_event_init(isa_bus);
     }
 #endif
diff --git a/qemu-config.c b/qemu-config.c
index 5c3296b..5ec5aa9 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -595,6 +595,10 @@ static QemuOptsList qemu_machine_opts = {
             .name = "dt_compatible",
             .type = QEMU_OPT_STRING,
             .help = "Overrides the \"compatible\" property of the dt root node",
+        }, {
+            .name = "enable_pv_event",
+            .type = QEMU_OPT_BOOL,
+            .help = "handle pv event"
         },
         { /* End of list */ }
     },
diff --git a/qemu-options.hx b/qemu-options.hx
index 97245a3..5661918 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -33,7 +33,8 @@ 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"
-    "                kvm_shadow_mem=size of KVM shadow MMU\n",
+    "                kvm_shadow_mem=size of KVM shadow MMU\n"
+    "                enable_pv_event=on|off controls pv event support\n",
     QEMU_ARCH_ALL)
 STEXI
 @item -machine [type=]@var{name}[,prop=@var{value}[,...]]
-- 
1.7.1