The LPC bridge/Host bridge IDs quirk is also not dependent on legacy
mode. Recent Windows driver no longer depends on these IDs, as well as
Linux i915 driver, while UEFI GOP seems still needs them. Make it an
option to allow users enabling and disabling it as needed.

Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
---
 hw/vfio/igd.c | 14 ++++++++------
 hw/vfio/pci.c |  2 ++
 hw/vfio/pci.h |  3 +++
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c
index 4c3862b61e..6775ce2eac 100644
--- a/hw/vfio/igd.c
+++ b/hw/vfio/igd.c
@@ -560,13 +560,9 @@ bool vfio_probe_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
             goto error;
         }
 
-        /* Enable OpRegion quirk */
+        /* Enable OpRegion and LPC brige quirk */
         vdev->features |= VFIO_FEATURE_ENABLE_IGD_OPREGION;
-
-        /* Setup LPC bridge / Host bridge PCI IDs */
-        if (!vfio_pci_igd_setup_lpc_bridge(vdev, &err)) {
-            goto error;
-        }
+        vdev->features |= VFIO_FEATURE_ENABLE_IGD_LPC;
     } else if (vdev->igd_legacy_mode == ON_OFF_AUTO_ON) {
         error_setg(&err,
                    "Machine is not i440fx or assigned BDF is not 00:02.0");
@@ -579,6 +575,12 @@ bool vfio_probe_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
         goto error;
     }
 
+    /* Setup LPC bridge / Host bridge PCI IDs */
+    if ((vdev->features & VFIO_FEATURE_ENABLE_IGD_LPC) &&
+        !vfio_pci_igd_setup_lpc_bridge(vdev, errp)) {
+        goto error;
+     }
+
     /*
      * Allow user to override dsm size using x-igd-gms option, in multiples of
      * 32MiB. This option should only be used when the desired size cannot be
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index c9a484fa68..d16cc5cc90 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3354,6 +3354,8 @@ static const Property vfio_pci_dev_properties[] = {
                     VFIO_FEATURE_ENABLE_REQ_BIT, true),
     DEFINE_PROP_BIT("x-igd-opregion", VFIOPCIDevice, features,
                     VFIO_FEATURE_ENABLE_IGD_OPREGION_BIT, false),
+    DEFINE_PROP_BIT("x-igd-lpc", VFIOPCIDevice, features,
+                    VFIO_FEATURE_ENABLE_IGD_LPC_BIT, false),
     DEFINE_PROP_ON_OFF_AUTO("x-igd-legacy-mode", VFIOPCIDevice,
                             igd_legacy_mode, ON_OFF_AUTO_AUTO),
     DEFINE_PROP_ON_OFF_AUTO("enable-migration", VFIOPCIDevice,
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index 0d0a18136a..a87333f3d5 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -154,6 +154,9 @@ struct VFIOPCIDevice {
 #define VFIO_FEATURE_ENABLE_IGD_OPREGION_BIT 2
 #define VFIO_FEATURE_ENABLE_IGD_OPREGION \
                                 (1 << VFIO_FEATURE_ENABLE_IGD_OPREGION_BIT)
+#define VFIO_FEATURE_ENABLE_IGD_LPC_BIT 3
+#define VFIO_FEATURE_ENABLE_IGD_LPC \
+                                (1 << VFIO_FEATURE_ENABLE_IGD_LPC_BIT)
     OnOffAuto display;
     uint32_t display_xres;
     uint32_t display_yres;
-- 
2.47.2