Re: [Qemu-riscv] [Qemu-devel] [PULL 15/54] build: convert pci.mak to Kconfig

[David Abdurachmanov]

On Thu, Mar 14, 2019 at 2:00 PM Michael S. Tsirkin <address@hidden> wrote:
>
> On Thu, Mar 14, 2019 at 01:53:48PM +0100, Andrea Bolognani wrote:
> > On Mon, 2019-03-04 at 19:19 +0100, Paolo Bonzini wrote:
> > > Instead of including the same list of devices for each target,
> > > set CONFIG_PCI to true, and make the devices default to present
> > > whenever PCI is available.  However, s390x does not want all the
> > > PCI devices, so there is a separate symbol to enable them.
> > [...]
> > > +++ b/default-configs/riscv32-softmmu.mak
> > > @@ -1,8 +1,8 @@
> > >  # Default configuration for riscv-softmmu
> > >
> > > -include pci.mak
> > >  include usb.mak
> > > -
> > > +CONFIG_PCI=y
> > > +CONFIG_PCI_DEVICES=y
> > >  CONFIG_SERIAL=y
> > >  CONFIG_VIRTIO_MMIO=y
> >
> > I *think* this might have caused some unwanted changes for RISC-V.
> >
> > pcie-root-port is built into qemu-system-riscv64 by default as of
> > dbbc277510aa (along with ioh3420!), but if you actually try to use it
> > you'll get:
> >
> >   $ ./riscv64-softmmu/qemu-system-riscv64 \
> >     -M virt \
> >     -device pcie-root-port
> >   qemu-system-riscv64: -device pcie-root-port: MSI-X is not
> >                        supported by interrupt controller
> >
> > This is a limitation we have been aware of, and the plan was to
> > enable the device in QEMU once it had been addressed: from the
> > libvirt side, the availability of the device would have meant that it
> > was safe to use it, but if the device is enabled in QEMU before it
> > can actually be used, then that makes detection on the libvirt side
> > problematic.
> >
> > I haven't spent time digging further - and I'm not familiar enough
> > with the QEMU build system anyway O:-) - but I wouldn't be surprised
> > if the same happened for other architectures, too.
>
> I'd say just disable it at build time by default.
> How about a dependency on BROKEN? Developers can
> enable it temporarily. Paolo?

Would it be enough to modify ./default-configs/riscv32-softmmu.mak by
adding:

CONFIG_PCIE_PORT=n

?
>
> > --
> > Andrea Bolognani / Red Hat / Virtualization