Some devices, such as IGD, require device-specific quirks to be applied
to their pci config spaces. Currently, these quirks are either part of
BAR quirk, or being a part of vfio_realize(). Add a placeholder for pci
config quirks for moving the quirks to one place later.

Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
---
 hw/vfio/pci-quirks.c | 5 +++++
 hw/vfio/pci.c        | 4 ++++
 hw/vfio/pci.h        | 1 +
 3 files changed, 10 insertions(+)

diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
index fbe43b0a79..c40e3ca88f 100644
--- a/hw/vfio/pci-quirks.c
+++ b/hw/vfio/pci-quirks.c
@@ -1167,6 +1167,11 @@ bool vfio_pci_igd_opregion_init(VFIOPCIDevice *vdev,
 /*
  * 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 ab17a98ee5..e624ae56c4 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3124,6 +3124,10 @@ 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);
     }
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index 43c166680a..5359e94f18 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -205,6 +205,7 @@ 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);
-- 
2.45.2