1. Patchew
  2. QEMU
  3. [PATCH 0/9] vfio/igd: Detect IGD by OpRegion and enable OpRegion automatically
  4. View patch

[PATCH 3/9] vfio/igd: Detect IGD device by OpRegion

Tomita Moeko posted 9 patches 9 months, 2 weeks ago
There is a newer version of this series
[PATCH 3/9] vfio/igd: Detect IGD device by OpRegion
Posted by Tomita Moeko 9 months, 2 weeks ago 
There is currently no straightforward way to distinguish if a Intel
graphics device is IGD or discrete GPU. However, only IGD devices have
OpRegion. Use the presence of VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION
to identify IGD devices. Still, OpRegion on hotplugged IGD device is
not supported.

Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
---
 hw/vfio/igd.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c
index ae19456457..d6880cbff7 100644
--- a/hw/vfio/igd.c
+++ b/hw/vfio/igd.c
@@ -185,9 +185,10 @@ static bool vfio_pci_igd_opregion_init(VFIOPCIDevice *vdev,
     return true;
 }
 
-static bool vfio_pci_igd_setup_opregion(VFIOPCIDevice *vdev, Error **errp)
+static bool vfio_pci_igd_opregion_detect(VFIOPCIDevice *vdev,
+                                         struct vfio_region_info **opregion,
+                                         Error **errp)
 {
-    g_autofree struct vfio_region_info *opregion = NULL;
     int ret;
 
     /* Hotplugging is not supported for opregion access */
@@ -198,17 +199,13 @@ static bool vfio_pci_igd_setup_opregion(VFIOPCIDevice *vdev, Error **errp)
 
     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);
+                    VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION, opregion);
     if (ret) {
         error_setg_errno(errp, -ret,
                          "Device does not supports IGD OpRegion feature");
         return false;
     }
 
-    if (!vfio_pci_igd_opregion_init(vdev, opregion, errp)) {
-        return false;
-    }
-
     return true;
 }
 
@@ -479,6 +476,7 @@ void vfio_probe_igd_bar0_quirk(VFIOPCIDevice *vdev, int nr)
 
 static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
 {
+    g_autofree struct vfio_region_info *opregion = NULL;
     int ret, gen;
     uint64_t gms_size;
     uint64_t *bdsm_size;
@@ -486,16 +484,17 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
     bool legacy_mode_enabled = false;
     Error *err = NULL;
 
-    /*
-     * This must be an Intel VGA device at address 00:02.0 for us to even
-     * consider enabling legacy mode.  The vBIOS has dependencies on the
-     * PCI bus address.
-     */
     if (!vfio_pci_is(vdev, PCI_VENDOR_ID_INTEL, PCI_ANY_ID) ||
         !vfio_is_vga(vdev)) {
         return true;
     }
 
+    /* IGD device always comes with OpRegion */
+    if (!vfio_pci_igd_opregion_detect(vdev, &opregion, errp)) {
+        return true;
+    }
+    info_report("OpRegion detected on Intel display %x.", vdev->device_id);
+
     /*
      * IGD is not a standard, they like to change their specs often.  We
      * only attempt to support back to SandBridge and we hope that newer
@@ -571,7 +570,7 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
 
     /* Setup OpRegion access */
     if ((vdev->features & VFIO_FEATURE_ENABLE_IGD_OPREGION) &&
-        !vfio_pci_igd_setup_opregion(vdev, errp)) {
+        !vfio_pci_igd_opregion_init(vdev, opregion, errp)) {
         goto error;
     }
 
@@ -671,8 +670,11 @@ error:
  */
 static bool vfio_pci_kvmgt_config_quirk(VFIOPCIDevice *vdev, Error **errp)
 {
+    g_autofree struct vfio_region_info *opregion = NULL;
+
     if ((vdev->features & VFIO_FEATURE_ENABLE_IGD_OPREGION) &&
-        !vfio_pci_igd_setup_opregion(vdev, errp)) {
+        (!vfio_pci_igd_opregion_detect(vdev, &opregion, errp) ||
+         !vfio_pci_igd_opregion_init(vdev, opregion, errp))) {
         return false;
     }
 
-- 
2.47.2
Re: [PATCH 3/9] vfio/igd: Detect IGD device by OpRegion
Posted by Corvin Köhne 9 months, 1 week ago 
On Tue, 2025-04-29 at 00:09 +0800, Tomita Moeko wrote:
> CAUTION: External Email!!
> There is currently no straightforward way to distinguish if a Intel
> graphics device is IGD or discrete GPU. However, only IGD devices have
> OpRegion. Use the presence of VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION
> to identify IGD devices. Still, OpRegion on hotplugged IGD device is
> not supported.
> 
> Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
> ---
>  hw/vfio/igd.c | 30 ++++++++++++++++--------------
>  1 file changed, 16 insertions(+), 14 deletions(-)
> 
> diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c
> index ae19456457..d6880cbff7 100644
> --- a/hw/vfio/igd.c
> +++ b/hw/vfio/igd.c
> @@ -185,9 +185,10 @@ static bool vfio_pci_igd_opregion_init(VFIOPCIDevice
> *vdev,
>      return true;
>  }
>  
> -static bool vfio_pci_igd_setup_opregion(VFIOPCIDevice *vdev, Error **errp)
> +static bool vfio_pci_igd_opregion_detect(VFIOPCIDevice *vdev,
> +                                         struct vfio_region_info **opregion,
> +                                         Error **errp)
>  {
> -    g_autofree struct vfio_region_info *opregion = NULL;
>      int ret;
>  
>      /* Hotplugging is not supported for opregion access */
> @@ -198,17 +199,13 @@ static bool vfio_pci_igd_setup_opregion(VFIOPCIDevice
> *vdev, Error **errp)
>  
>      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);
> +                    VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION, opregion);
>      if (ret) {
>          error_setg_errno(errp, -ret,
>                           "Device does not supports IGD OpRegion feature");
>          return false;
>      }
>  
> -    if (!vfio_pci_igd_opregion_init(vdev, opregion, errp)) {
> -        return false;
> -    }
> -
>      return true;
>  }
>  
> @@ -479,6 +476,7 @@ void vfio_probe_igd_bar0_quirk(VFIOPCIDevice *vdev, int
> nr)
>  
>  static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
>  {
> +    g_autofree struct vfio_region_info *opregion = NULL;
>      int ret, gen;
>      uint64_t gms_size;
>      uint64_t *bdsm_size;
> @@ -486,16 +484,17 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice
> *vdev, Error **errp)
>      bool legacy_mode_enabled = false;
>      Error *err = NULL;
>  
> -    /*
> -     * This must be an Intel VGA device at address 00:02.0 for us to even
> -     * consider enabling legacy mode.  The vBIOS has dependencies on the
> -     * PCI bus address.
> -     */
>      if (!vfio_pci_is(vdev, PCI_VENDOR_ID_INTEL, PCI_ANY_ID) ||
>          !vfio_is_vga(vdev)) {
>          return true;
>      }
>  
> +    /* IGD device always comes with OpRegion */
> +    if (!vfio_pci_igd_opregion_detect(vdev, &opregion, errp)) {
> +        return true;
> +    }
> +    info_report("OpRegion detected on Intel display %x.", vdev->device_id);
> +
>      /*
>       * IGD is not a standard, they like to change their specs often.  We
>       * only attempt to support back to SandBridge and we hope that newer
> @@ -571,7 +570,7 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev,
> Error **errp)
>  
>      /* Setup OpRegion access */
>      if ((vdev->features & VFIO_FEATURE_ENABLE_IGD_OPREGION) &&
> -        !vfio_pci_igd_setup_opregion(vdev, errp)) {
> +        !vfio_pci_igd_opregion_init(vdev, opregion, errp)) {
>          goto error;
>      }
>  
> @@ -671,8 +670,11 @@ error:
>   */
>  static bool vfio_pci_kvmgt_config_quirk(VFIOPCIDevice *vdev, Error **errp)
>  {
> +    g_autofree struct vfio_region_info *opregion = NULL;
> +
>      if ((vdev->features & VFIO_FEATURE_ENABLE_IGD_OPREGION) &&
> -        !vfio_pci_igd_setup_opregion(vdev, errp)) {
> +        (!vfio_pci_igd_opregion_detect(vdev, &opregion, errp) ||
> +         !vfio_pci_igd_opregion_init(vdev, opregion, errp))) {
>          return false;
>      }
>  

Reviewed-by: Corvin Köhne <c.koehne@beckhoff.com>


-- 
Kind regards,
Corvin

Patchew 2.1-devel-b67e4c2

© 2016 - 2026 Red Hat, Inc.