Introduce x-pci-class-code option to allow users to override PCI class code of a device, similar to the existing x-pci-vendor-id option. Only the lower 24 bits of this option are used, though a uint32 is used here for determining whether the value is valid and set by user.
Additionally, to prevent exposing VGA ranges on non-VGA devices, the x-vga=on option requires x-pci-class-code is either unset or set to VGA controller class. This is mainly intended for IGD devices that expose themselves either as VGA controller (primary display) or Display controller (non-primary display). The UEFI GOP driver depends on the device reporting a VGA controller class code (0x030000). Signed-off-by: Tomita Moeko <tomitamo...@gmail.com> --- v2: * Add vdev class code check in vfio_populate_vga(). * Fix type in trace-events. Link: https://lore.kernel.org/all/20250524153102.19747-1-tomitamo...@gmail.com/ hw/vfio/pci.c | 25 +++++++++++++++++++++++++ hw/vfio/pci.h | 1 + hw/vfio/trace-events | 1 + 3 files changed, 27 insertions(+) diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index b1250d85bf..d57cb7356e 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -2726,6 +2726,14 @@ bool vfio_populate_vga(VFIOPCIDevice *vdev, Error **errp) return false; } + /* vdev class should be either unmodified (PCI_ANY_ID), or VGA controller */ + if ((vdev->class_code != PCI_ANY_ID) && + (vdev->class_code != (PCI_CLASS_DISPLAY_VGA << 8)) && + (vdev->class_code != (PCI_CLASS_NOT_DEFINED_VGA << 8))) { + error_setg(errp, "vdev is not a VGA device"); + return false; + } + if (!(reg_info->flags & VFIO_REGION_INFO_FLAG_READ) || !(reg_info->flags & VFIO_REGION_INFO_FLAG_WRITE) || reg_info->size < 0xbffff + 1) { @@ -3092,6 +3100,21 @@ static bool vfio_pci_config_setup(VFIOPCIDevice *vdev, Error **errp) vdev->sub_device_id); } + /* + * Class code is a 24-bit value at config space 0x09. Allow overriding it + * with any 24-bit value. + */ + if (vdev->class_code != PCI_ANY_ID) { + if (vdev->class_code > 0xffffff) { + error_setg(errp, "invalid PCI class code provided"); + return false; + } + /* Higher 24 bits of PCI_CLASS_REVISION are class code */ + vfio_add_emulated_long(vdev, PCI_CLASS_REVISION, + vdev->class_code << 8, ~0xff); + trace_vfio_pci_emulated_class_code(vbasedev->name, vdev->class_code); + } + /* QEMU can change multi-function devices to single function, or reverse */ vdev->emulated_config_bits[PCI_HEADER_TYPE] = PCI_HEADER_TYPE_MULTI_FUNCTION; @@ -3489,6 +3512,8 @@ static const Property vfio_pci_dev_properties[] = { sub_vendor_id, PCI_ANY_ID), DEFINE_PROP_UINT32("x-pci-sub-device-id", VFIOPCIDevice, sub_device_id, PCI_ANY_ID), + DEFINE_PROP_UINT32("x-pci-class-code", VFIOPCIDevice, + class_code, PCI_ANY_ID), DEFINE_PROP_UINT32("x-igd-gms", VFIOPCIDevice, igd_gms, 0), DEFINE_PROP_UNSIGNED_NODEFAULT("x-nv-gpudirect-clique", VFIOPCIDevice, nv_gpudirect_clique, diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h index 5ce0fb916f..587eb8cc9a 100644 --- a/hw/vfio/pci.h +++ b/hw/vfio/pci.h @@ -156,6 +156,7 @@ struct VFIOPCIDevice { uint32_t device_id; uint32_t sub_vendor_id; uint32_t sub_device_id; + uint32_t class_code; uint32_t features; #define VFIO_FEATURE_ENABLE_VGA_BIT 0 #define VFIO_FEATURE_ENABLE_VGA (1 << VFIO_FEATURE_ENABLE_VGA_BIT) diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events index e90ec9bff8..e8d585b49a 100644 --- a/hw/vfio/trace-events +++ b/hw/vfio/trace-events @@ -46,6 +46,7 @@ vfio_pci_emulated_vendor_id(const char *name, uint16_t val) "%s 0x%04x" vfio_pci_emulated_device_id(const char *name, uint16_t val) "%s 0x%04x" vfio_pci_emulated_sub_vendor_id(const char *name, uint16_t val) "%s 0x%04x" vfio_pci_emulated_sub_device_id(const char *name, uint16_t val) "%s 0x%04x" +vfio_pci_emulated_class_code(const char *name, uint32_t val) "%s 0x%06x" # pci-quirks.c vfio_quirk_rom_in_denylist(const char *name, uint16_t vid, uint16_t did) "%s %04x:%04x" -- 2.47.2
