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

Tomita Moeko posted 1 patch 3 months ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20250813160510.23553-1-tomitamoeko@gmail.com
Maintainers: Alex Williamson <alex.williamson@redhat.com>, "Cédric Le Goater" <clg@redhat.com>, Tomita Moeko <tomitamoeko@gmail.com>
hw/vfio/igd.c | 7 ++++---
hw/vfio/pci.h | 5 +++++
2 files changed, 9 insertions(+), 3 deletions(-)
[PATCH] vfio/igd: Enable quirks when IGD is not the primary display
Posted by Tomita Moeko 3 months ago 
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
Re: [PATCH] vfio/igd: Enable quirks when IGD is not the primary display
Posted by Michael Tokarev 2 months ago 
On 13.08.2025 19:05, Tomita Moeko wrote:
> 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.

This feels like qemu-stable material (10.0.x & 10.1.x), is it not?

Thanks,

/mjt

> 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,
Re: [PATCH] vfio/igd: Enable quirks when IGD is not the primary display
Posted by Cédric Le Goater 2 months, 1 week ago 
On 8/13/25 18:05, Tomita Moeko wrote:
> 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>


Applied to vfio-next.

Thanks,

C.
Re: [PATCH] vfio/igd: Enable quirks when IGD is not the primary display
Posted by Alex Williamson 3 months ago 
On Thu, 14 Aug 2025 00:05:10 +0800
Tomita Moeko <tomitamoeko@gmail.com> wrote:

> 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(-)

Reviewed-by: Alex Williamson <alex.williamson@redhat.com>

Patchew 2.1-devel-b67e4c2

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