Re: [Qemu-devel] [PATCH v5 0/5] Connect a PCIe host and graphics support to RISC-V

[Andrea Bolognani]

On Thu, 2018-10-04 at 20:06 +0000, Alistair Francis wrote:
> Alistair Francis (5):
>   hw/riscv/virt: Increase the number of interrupts
>   hw/riscv/virt: Connect the gpex PCIe
>   riscv: Enable VGA and PCIE_VGA
>   hw/riscv/sifive_u: Connect the Xilinx PCIe
>   hw/riscv/virt: Connect a VirtIO net PCIe device
> 
>  default-configs/riscv32-softmmu.mak | 10 +++-
>  default-configs/riscv64-softmmu.mak | 10 +++-
>  hw/riscv/sifive_u.c                 | 64 +++++++++++++++++++++++++
>  hw/riscv/virt.c                     | 72 +++++++++++++++++++++++++++++
>  include/hw/riscv/sifive_u.h         |  4 +-
>  include/hw/riscv/virt.h             |  6 ++-
>  6 files changed, 161 insertions(+), 5 deletions(-)

I gave v4 a try a few weeks ago because I wanted to see what would
be needed to wire this up on the libvirt side. Turns out, not much
really :)

I still have a couple of questions that hopefully you'll be able
to answer:

* what should libvirt look for to figure out whether or not a RISC-V
  guest will have PCI support? For aarch64 we look for the presence
  of the 'gpex-pcihost' device, but of course that won't work for
  RISC-V so we need something else;

* I have succesfully started a RISC-V guest with virtio-pci devices
  attached but, while they show up in 'info qtree' and friends, the
  guest OS itself doesn't seem to recognize any of them - not even
  pcie.0! I'm using the guest images listed at [1] and following the
  corresponding instructions, but I think the BBL build (config at
  [2]) is missing some feature... Any ideas what we would need to
  add there?

If you can help with these I'll give the patches another spin and
gladly provide my Tested-by :)


[1] https://fedoraproject.org/wiki/Architectures/RISC-V/Installing
[2] https://github.com/rwmjones/fedora-riscv-kernel/blob/master/config
-- 
Andrea Bolognani / Red Hat / Virtualization