[PULL 09/21] vfio/igd: Introduce x-igd-lpc option for LPC bridge ID quirk

["Cédric Le Goater" <clg@redhat.com>]

From: Tomita Moeko <tomitamoeko@gmail.com>

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>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Corvin Köhne <c.koehne@beckhoff.com>
Link: https://lore.kernel.org/qemu-devel/20250306180131.32970-10-tomitamoeko@gmail.com
[ clg: - Fixed spelling in vfio_probe_igd_config_quirk() ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 hw/vfio/pci.h |  3 +++
 hw/vfio/igd.c | 14 ++++++++------
 hw/vfio/pci.c |  2 ++
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index 816bdbf844dc17e7cbac9a6f42daf9a448ab9cc0..d94ecaba689c4681687c0a6796ffbcda522ae179 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;
diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c
index 12e07517b4a09ef87791acc09f6a6120abf17ae5..8a88dbab13ede764d0610a043132a3acfe208134 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 bridge 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 e2897bdcd58d092d64689b5921a34c133139b56d..3cb7806f2f219174ffb7d28595e9430b41ee40ae 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3360,6 +3360,8 @@ 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,
-- 
2.48.1