Re: [Qemu-devel] [PATCH v1 1/1] riscv: plic: Set msi_nonbroken as true

[Peter Maydell]

On Mon, 18 Mar 2019 at 08:59, Markus Armbruster <address@hidden> wrote:
>
> Alistair Francis <address@hidden> writes:
>
> > Set msi_nonbroken as true for the PLIC.
> >
> > According to the comment located here:
> > https://git.qemu.org/?p=qemu.git;a=blob;f=hw/pci/msi.c;h=47d2b0f33c664533b8dbd5cb17faa8e6a01afe1f;hb=HEAD#l38
> > the msi_nonbroken variable should be set to true even if they don't
> > support MSI. In this case that is what we are doing as we don't support
> > MSI.
> >
> > Signed-off-by: Alistair Francis <address@hidden>
> > Reported-by: Andrea Bolognani <address@hidden>
> > Reported-by: David Abdurachmanov <address@hidden>
> > ---
> > This should allow working pcie-root-ports in QEMU and allow libvirt
> > to start using PCIe by default for RISC-V guests.
>
> Lovely!  If more people reviewed and updated their interrupt controllers
> this way, we'd be in better shape.

Why do we have a flag which each interrupt controller
has to set rather than just making the right thing the
default (and having the one or two interrupt controllers
that need the wrong thing for backwards compatibility reasons
be the ones that have to set the flag) ? This way round makes
it way to easy to add a new interrupt controller with this
bug without noticing it, I think.

thanks
-- PMM