Intel only provides legacy VBIOS for IGD up to Gen9, and there is no CSM support on later devices. Additionally, Seabios can only handle 32-bit BDSM register used until Gen9. Since legacy mode requires VGA capability, restrict it to Gen6 through Gen9 devices.
Link: https://lore.kernel.org/qemu-devel/20250325172239.27926-1-tomitamo...@gmail.com/T/ Signed-off-by: Tomita Moeko <tomitamo...@gmail.com> --- docs/igd-assign.txt | 1 + hw/vfio/igd.c | 6 +++++- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/docs/igd-assign.txt b/docs/igd-assign.txt index 3aed7956d5..95beb76812 100644 --- a/docs/igd-assign.txt +++ b/docs/igd-assign.txt @@ -47,6 +47,7 @@ Intel document [1] shows how to dump VBIOS to file. For UEFI Option ROM, see QEMU also provides a "Legacy" mode that implicitly enables full functionality on IGD, it is automatically enabled when +* IGD generation is 6 to 9 (Sandy Bridge to Comet Lake) * Machine type is i440fx * IGD is assigned to guest BDF 00:02.0 * ROM BAR or romfile is present diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c index 6678e0e5cd..cecc3245b7 100644 --- a/hw/vfio/igd.c +++ b/hw/vfio/igd.c @@ -516,11 +516,13 @@ 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) * - 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) && !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)))) { @@ -565,7 +567,9 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp) vdev->features |= VFIO_FEATURE_ENABLE_IGD_LPC; } else if (vdev->igd_legacy_mode == ON_OFF_AUTO_ON) { error_setg(&err, - "Machine is not i440fx or assigned BDF is not 00:02.0"); + "Machine is not i440fx, assigned BDF is not 00:02.0, " + "or device %04x (gen %d) doesn't support legacy mode", + vdev->device_id, gen); goto error; } -- 2.47.2
