[PATCH] vfio/igd: Enable quirks when IGD is not the primary display

[Tomita Moeko <tomitamoeko@gmail.com>]

Since linux 6.15, commit 41112160ca87 ("vfio/pci: match IGD devices in
display controller class"), IGD related regions are also exposed when
IGD is not primary display (device class is Display controller).

Allow IGD quirks to be enabled in this configuration so that guests can
have display output on IGD when it is not the primary display.

Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
---
 hw/vfio/igd.c | 7 ++++---
 hw/vfio/pci.h | 5 +++++
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c
index ee0767b0b8..f116c40ccd 100644
--- a/hw/vfio/igd.c
+++ b/hw/vfio/igd.c
@@ -460,7 +460,7 @@ void vfio_probe_igd_bar0_quirk(VFIOPCIDevice *vdev, int nr)
     int gen;
 
     if (!vfio_pci_is(vdev, PCI_VENDOR_ID_INTEL, PCI_ANY_ID) ||
-        !vfio_is_vga(vdev) || nr != 0) {
+        !vfio_is_base_display(vdev) || nr != 0) {
         return;
     }
 
@@ -518,7 +518,7 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
     Error *err = NULL;
 
     if (!vfio_pci_is(vdev, PCI_VENDOR_ID_INTEL, PCI_ANY_ID) ||
-        !vfio_is_vga(vdev)) {
+        !vfio_is_base_display(vdev)) {
         return true;
     }
 
@@ -534,12 +534,13 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
     /*
      * For backward compatibility, enable legacy mode when
      * - Device geneation is 6 to 9 (including both)
-     * - IGD claims VGA cycles on host
+     * - IGD exposes itself as VGA controller and claims VGA cycles on host
      * - Machine type is i440fx (pc_piix)
      * - IGD device is at guest BDF 00:02.0
      * - Not manually disabled by x-igd-legacy-mode=off
      */
     if ((vdev->igd_legacy_mode != ON_OFF_AUTO_OFF) &&
+        vfio_is_vga(vdev) &&
         (gen >= 6 && gen <= 9) &&
         !(gmch & IGD_GMCH_VGA_DISABLE) &&
         !strcmp(MACHINE_GET_CLASS(qdev_get_machine())->family, "pc_piix") &&
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index 810a842f4a..923cf9c2f7 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -203,6 +203,11 @@ static inline bool vfio_is_vga(VFIOPCIDevice *vdev)
     return (vdev->class_code >> 8) == PCI_CLASS_DISPLAY_VGA;
 }
 
+static inline bool vfio_is_base_display(VFIOPCIDevice *vdev)
+{
+    return (vdev->class_code >> 16) == PCI_BASE_CLASS_DISPLAY;
+}
+
 /* MSI/MSI-X/INTx */
 void vfio_pci_vector_init(VFIOPCIDevice *vdev, int nr);
 void vfio_pci_add_kvm_msi_virq(VFIOPCIDevice *vdev, VFIOMSIVector *vector,
-- 
2.50.1