1 files changed, 22 insertions, 19 deletions

diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c
index e7952d1..ee0767b 100644
--- a/hw/vfio/igd.c
+++ b/hw/vfio/igd.c
@@ -113,6 +113,7 @@ static int igd_gen(VFIOPCIDevice *vdev)
 #define IGD_BDSM 0x5c /* Base Data of Stolen Memory */
 #define IGD_BDSM_GEN11 0xc0 /* Base Data of Stolen Memory of gen 11 and later */
 
+#define IGD_GMCH_VGA_DISABLE        BIT(1)
 #define IGD_GMCH_GEN6_GMS_SHIFT     3       /* SNB_GMCH in i915 */
 #define IGD_GMCH_GEN6_GMS_MASK      0x1f
 #define IGD_GMCH_GEN8_GMS_SHIFT     8       /* BDW_GMCH in i915 */
@@ -187,23 +188,21 @@ static bool vfio_pci_igd_opregion_init(VFIOPCIDevice *vdev,
 }
 
 static bool vfio_pci_igd_opregion_detect(VFIOPCIDevice *vdev,
-                                         struct vfio_region_info **opregion,
-                                         Error **errp)
+                                         struct vfio_region_info **opregion)
 {
     int ret;
 
-    /* Hotplugging is not supported for opregion access */
-    if (vdev->pdev.qdev.hotplugged) {
-        error_setg(errp, "IGD OpRegion is not supported on hotplugged device");
-        return false;
-    }
-
     ret = vfio_device_get_region_info_type(&vdev->vbasedev,
                     VFIO_REGION_TYPE_PCI_VENDOR_TYPE | PCI_VENDOR_ID_INTEL,
                     VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION, opregion);
     if (ret) {
-        error_setg_errno(errp, -ret,
-                         "Device does not supports IGD OpRegion feature");
+        return false;
+    }
+
+    /* Hotplugging is not supported for opregion access */
+    if (vdev->pdev.qdev.hotplugged) {
+        warn_report("IGD device detected, but OpRegion is not supported "
+                    "on hotplugged device.");
         return false;
     }
 
@@ -524,7 +523,7 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
     }
 
     /* IGD device always comes with OpRegion */
-    if (!vfio_pci_igd_opregion_detect(vdev, &opregion, errp)) {
+    if (!vfio_pci_igd_opregion_detect(vdev, &opregion)) {
         return true;
     }
     info_report("OpRegion detected on Intel display %x.", vdev->device_id);
@@ -535,12 +534,14 @@ 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
      * - 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) &&
         (gen >= 6 && gen <= 9) &&
+        !(gmch & IGD_GMCH_VGA_DISABLE) &&
         !strcmp(MACHINE_GET_CLASS(qdev_get_machine())->family, "pc_piix") &&
         (&vdev->pdev == pci_find_device(pci_device_root_bus(&vdev->pdev),
         0, PCI_DEVFN(0x2, 0)))) {
@@ -570,14 +571,16 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
         }
 
         /*
-         * If IGD VGA Disable is clear (expected) and VGA is not already
-         * enabled, try to enable it. Probably shouldn't be using legacy mode
-         * without VGA, but also no point in us enabling VGA if disabled in
-         * hardware.
+         * If VGA is not already enabled, try to enable it. We shouldn't be
+         * using legacy mode without VGA.
          */
-        if (!(gmch & 0x2) && !vdev->vga && !vfio_populate_vga(vdev, &err)) {
-            error_setg(&err, "Unable to enable VGA access");
-            goto error;
+        if (!vdev->vga) {
+            if (vfio_populate_vga(vdev, &err)) {
+                vfio_pci_config_register_vga(vdev);
+            } else {
+                error_setg(&err, "Unable to enable VGA access");
+                goto error;
+            }
         }
 
         /* Enable OpRegion and LPC bridge quirk */
@@ -695,7 +698,7 @@ static bool vfio_pci_kvmgt_config_quirk(VFIOPCIDevice *vdev, Error **errp)
         return true;
     }
 
-    if (!vfio_pci_igd_opregion_detect(vdev, &opregion, errp)) {
+    if (!vfio_pci_igd_opregion_detect(vdev, &opregion)) {
         /* Should never reach here, KVMGT always emulates OpRegion */
         return false;
     }