From: Tomita Moeko <tomitamoeko@gmail.com>

IGD devices require device-specific quirk to be applied to their PCI
config space. Currently, it is put in the BAR4 quirk that does nothing
to BAR4 itself. Add a placeholder for PCI config space quirks to hold
that quirk later.

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/20250306180131.32970-6-tomitamoeko@gmail.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 hw/vfio/pci.h        | 1 +
 hw/vfio/pci-quirks.c | 5 +++++
 hw/vfio/pci.c        | 4 ++++
 3 files changed, 10 insertions(+)

diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index f660b0d80fcfcb81129d443732fe887b084d7a52..d125e738655a43ec01348b784af90f7e121bd695 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -204,6 +204,7 @@ uint64_t vfio_vga_read(void *opaque, hwaddr addr, unsigned size);
 void vfio_vga_write(void *opaque, hwaddr addr, uint64_t data, unsigned size);
 
 bool vfio_opt_rom_in_denylist(VFIOPCIDevice *vdev);
+bool vfio_config_quirk_setup(VFIOPCIDevice *vdev, Error **errp);
 void vfio_vga_quirk_setup(VFIOPCIDevice *vdev);
 void vfio_vga_quirk_exit(VFIOPCIDevice *vdev);
 void vfio_vga_quirk_finalize(VFIOPCIDevice *vdev);
diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
index 37966e17f0178bbf2d82b2d84da40ba2e261d9f3..78aef7d60eff7f8e776c030942439523b2197ded 100644
--- a/hw/vfio/pci-quirks.c
+++ b/hw/vfio/pci-quirks.c
@@ -1117,6 +1117,11 @@ static void vfio_probe_rtl8168_bar2_quirk(VFIOPCIDevice *vdev, int nr)
 /*
  * Common quirk probe entry points.
  */
+bool vfio_config_quirk_setup(VFIOPCIDevice *vdev, Error **errp)
+{
+    return true;
+}
+
 void vfio_vga_quirk_setup(VFIOPCIDevice *vdev)
 {
     vfio_vga_probe_ati_3c3_quirk(vdev);
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 419dc2c4c85ffeed3b794e65f8040e11ba58bb0e..ff1e720dbadc2251d76e4c71c026757e2cef1a8c 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3128,6 +3128,10 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
         goto out_unset_idev;
     }
 
+    if (!vfio_config_quirk_setup(vdev, errp)) {
+        goto out_unset_idev;
+    }
+
     if (vdev->vga) {
         vfio_vga_quirk_setup(vdev);
     }
-- 
2.48.1