[Qemu-devel] TCP based PCIE request forwarding

[lementec fabien <fabien.lementec@gmail.com>]

Hi,

I am a software engineer who works in an electronic group. Using QEMU
to emulate devices allows me to start writing and testing LINUX software
before the device is actually available. In the group, we are mostly
working with XILINX FPGAs, communicating with the host via PCIE. The
devices are implemented in VHDL.

I wanted to be able to reuse our VHDL designs in QEMU. To this end,
I implemented a QEMU TCP based PCIE request forwarder, so that I can
emulate our device in a standard process, and use the GHDL GCC frontend
plus some glue.

The fact that it is TCP based allows me to run the device on another
machine, which is a requirement.

The whole thing is available here:
https://github.com/texane/vpcie

The request forwarder is available here:
https://github.com/texane/vpcie/blob/master/qemu/pciefw.c

It requires a patch to QEMU, available here:
https://github.com/texane/vpcie/blob/master/qemu/qemu_58617a795c8067b2f9800cffce60f38707d3aa31.diff

Since I am the only one using it and I wanted a working version soon,
I use a naive method to plug into QEMU, which can block the VM. Plus,
I did not take care of some PCIE related details. But it works well
enough.

Do you think the approach of forwarding PCIE requests over TCP could
be integrated to QEMU? If positive, what kind of modifications should
be done to this patch?

Best regards,

Fabien Le Mentec.