Re: [PATCH] hw/vfio: Move the IGD quirk code to a separate file

[Philippe Mathieu-Daudé]

On 1/14/20 7:47 PM, Alex Williamson wrote:
> On Tue, 14 Jan 2020 18:10:26 +0100
> Philippe Mathieu-Daudé <address@hidden> wrote:
>
> > On 1/14/20 5:17 PM, Thomas Huth wrote:
> > > The IGD quirk code defines a separate device, the so-called
> > > "vfio-pci-igd-lpc-bridge" which shows up as a user-creatable
> > > device in all QEMU binaries that include the vfio code. This
> > > is a little bit unfortunate for two reasons: First, this device
> > > is completely useless in binaries like qemu-system-s390x.
> > > Second we also would like to disable it in downstream RHEL
> > > which currently requires some extra patches there since the
> > > device does not have a proper Kconfig-style switch yet.
> > >
> > > So it would be good if the device could be disabled more easily,
> > > thus let's move the code to a separate file instead and introduce
> > > a proper Kconfig switch for it which gets only enabled by default
> > > if we also have CONFIG_PC_PCI enabled.
> > >
> > > Signed-off-by: Thomas Huth <address@hidden>
> > > ---
> > >    hw/vfio/Kconfig       |   5 +
> > >    hw/vfio/Makefile.objs |   1 +
> > >    hw/vfio/igd.c         | 616 ++++++++++++++++++++++++++++++++++++++++++
> > >    hw/vfio/pci-quirks.c  | 614 +----------------------------------------
> > >    hw/vfio/pci.h         |  17 ++
> > >    5 files changed, 642 insertions(+), 611 deletions(-)
> > >    create mode 100644 hw/vfio/igd.c
> > >
> > > diff --git a/hw/vfio/Kconfig b/hw/vfio/Kconfig
> > > index f0eaa75ce7..7cdba0560a 100644
> > > --- a/hw/vfio/Kconfig
> > > +++ b/hw/vfio/Kconfig
> > > @@ -36,3 +36,8 @@ config VFIO_AP
> > >        default y
> > >        select VFIO
> > >        depends on LINUX && S390_CCW_VIRTIO
> > > +
> > > +config VFIO_IGD
> > > +    bool
> > > +    default y if PC_PCI
> >
> > With the details from Alex here:
> > https://www.mail-archive.com/address@hidden/msg663667.html
> >
> > I'm tempted to use:
> >
> >       default y if XEN
> >       depends on PC_PCI
>
> I think you might be confused, there are two separate LPC bridges in
> QEMU for IGD support, one specifically for Xen and this one
> specifically for VFIO.  This one is never used in a Xen environment.

Argh I see, OK!

> > Watch out the Xen Kconfig seems fragile, yesterday using --enable-xen
> > --disable-tcg I hit this build error:
> >
> >     LINK    i386-softmmu/qemu-system-i386
> > /usr/bin/ld: hw/xen/xen_pt.o: in function
> > `xen_igd_passthrough_isa_bridge_create':
> > /home/phil/source/qemu/hw/xen/xen_pt.c:701: undefined reference to
> > `igd_passthrough_isa_bridge_create'
> >
> > > +    depends on VFIO_PCI
> > > diff --git a/hw/vfio/Makefile.objs b/hw/vfio/Makefile.objs
> > > index abad8b818c..9bb1c09e84 100644
> > > --- a/hw/vfio/Makefile.objs
> > > +++ b/hw/vfio/Makefile.objs
> > > @@ -5,3 +5,4 @@ obj-$(CONFIG_VFIO_PLATFORM) += platform.o
> > >    obj-$(CONFIG_VFIO_XGMAC) += calxeda-xgmac.o
> > >    obj-$(CONFIG_VFIO_AMD_XGBE) += amd-xgbe.o
> > >    obj-$(CONFIG_VFIO_AP) += ap.o
> > > +obj-$(CONFIG_VFIO_IGD) += igd.o