Re: [PATCH v2 12/21] hw/vfio/igd: Check CONFIG_VFIO_IGD at runtime using vfio_igd_builtin()

["Cédric Le Goater" <clg@redhat.com>]

On 3/9/25 00:09, Philippe Mathieu-Daudé wrote:
> Convert the compile time check on the CONFIG_VFIO_IGD definition
> by a runtime one by calling vfio_igd_builtin(), which check
> whether VFIO_IGD is built in a qemu-system binary.
> 
> Add stubs to avoid when VFIO_IGD is not built in:

I thought we were trying to avoid stubs in QEMU build. Did that change ?


Thanks,

C.


> 
>    /usr/bin/ld: libqemu-x86_64-softmmu.a.p/hw_vfio_pci-quirks.c.o: in function `vfio_bar_quirk_setup':
>    /usr/bin/ld: ../hw/vfio/pci-quirks.c:1216: undefined reference to `vfio_probe_igd_bar0_quirk'
>    /usr/bin/ld: ../hw/vfio/pci-quirks.c:1217: undefined reference to `vfio_probe_igd_bar4_quirk'
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>   hw/vfio/pci-quirks.h |  6 ++++++
>   hw/vfio/igd-stubs.c  | 20 ++++++++++++++++++++
>   hw/vfio/pci-quirks.c |  9 ++++-----
>   hw/vfio/meson.build  |  3 +++
>   4 files changed, 33 insertions(+), 5 deletions(-)
>   create mode 100644 hw/vfio/igd-stubs.c
> 
> diff --git a/hw/vfio/pci-quirks.h b/hw/vfio/pci-quirks.h
> index fdaa81f00aa..dcdb1962600 100644
> --- a/hw/vfio/pci-quirks.h
> +++ b/hw/vfio/pci-quirks.h
> @@ -13,6 +13,7 @@
>   #define HW_VFIO_VFIO_PCI_QUIRKS_H
>   
>   #include "qemu/osdep.h"
> +#include "qom/object.h"
>   #include "exec/memop.h"
>   
>   /*
> @@ -71,4 +72,9 @@ extern const MemoryRegionOps vfio_generic_mirror_quirk;
>   
>   #define TYPE_VFIO_PCI_IGD_LPC_BRIDGE "vfio-pci-igd-lpc-bridge"
>   
> +static inline bool vfio_igd_builtin(void)
> +{
> +    return type_is_registered(TYPE_VFIO_PCI_IGD_LPC_BRIDGE);
> +}
> +
>   #endif /* HW_VFIO_VFIO_PCI_QUIRKS_H */
> diff --git a/hw/vfio/igd-stubs.c b/hw/vfio/igd-stubs.c
> new file mode 100644
> index 00000000000..5d4e88aeb1b
> --- /dev/null
> +++ b/hw/vfio/igd-stubs.c
> @@ -0,0 +1,20 @@
> +/*
> + * IGD device quirk stubs
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + *
> + * Copyright (C) Linaro, Ltd.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "pci.h"
> +
> +void vfio_probe_igd_bar0_quirk(VFIOPCIDevice *vdev, int nr)
> +{
> +    g_assert_not_reached();
> +}
> +
> +void vfio_probe_igd_bar4_quirk(VFIOPCIDevice *vdev, int nr)
> +{
> +    g_assert_not_reached();
> +}
> diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
> index c53591fe2ba..22cb35af8cc 100644
> --- a/hw/vfio/pci-quirks.c
> +++ b/hw/vfio/pci-quirks.c
> @@ -11,7 +11,6 @@
>    */
>   
>   #include "qemu/osdep.h"
> -#include CONFIG_DEVICES
>   #include "exec/memop.h"
>   #include "qemu/units.h"
>   #include "qemu/log.h"
> @@ -1213,10 +1212,10 @@ void vfio_bar_quirk_setup(VFIOPCIDevice *vdev, int nr)
>       vfio_probe_nvidia_bar5_quirk(vdev, nr);
>       vfio_probe_nvidia_bar0_quirk(vdev, nr);
>       vfio_probe_rtl8168_bar2_quirk(vdev, nr);
> -#ifdef CONFIG_VFIO_IGD
> -    vfio_probe_igd_bar0_quirk(vdev, nr);
> -    vfio_probe_igd_bar4_quirk(vdev, nr);
> -#endif
> +    if (vfio_igd_builtin()) {
> +        vfio_probe_igd_bar0_quirk(vdev, nr);
> +        vfio_probe_igd_bar4_quirk(vdev, nr);
> +    }
>   }
>   
>   void vfio_bar_quirk_exit(VFIOPCIDevice *vdev, int nr)
> diff --git a/hw/vfio/meson.build b/hw/vfio/meson.build
> index a8939c83865..6ab711d0539 100644
> --- a/hw/vfio/meson.build
> +++ b/hw/vfio/meson.build
> @@ -17,6 +17,9 @@ specific_ss.add_all(when: 'CONFIG_VFIO', if_true: vfio_ss)
>   
>   system_ss.add(when: 'CONFIG_VFIO_XGMAC', if_true: files('calxeda-xgmac.c'))
>   system_ss.add(when: 'CONFIG_VFIO_AMD_XGBE', if_true: files('amd-xgbe.c'))
> +system_ss.add(when: 'CONFIG_VFIO_IGD', if_false: files(
> +  'igd-stubs.c',
> +))
>   system_ss.add(when: 'CONFIG_VFIO', if_true: files(
>     'helpers.c',
>     'container-base.c',