[seL4] Re: ethernet pass-through using CAmkES VM on x86

On Wed, Sep 29, 2021 at 6:23 PM William ML Leslie wrote:

On Wed, 29 Sept 2021 at 18:10, erickaoakes--- via Devel wrote:

...

Hi Kent,

...

Unfortunately setting up passthrough devices on x86 for camkes-vm apps is pretty painful.

It appears that your answer is specific to QEMU x64? Is setting up passthrough devices on x64 bare metal similarly painful?

Yea, essentially CAMKES is missing a plugin for calculating the hardware resources that a particular PCI device would need. There is a plugin for doing this with Arm and RISCV using flattened device trees, but it would be more complicated for x86 because the device hierarchy is dynamically calculated at startup so a plugin would need to be able to either run a program on the platform and dump this information in a format that the camkes tooling could then turn into seL4 hardware caps or some other way of precalculating what hardware resources a device will end up with. Because there's no plugin for doing this, it currently must be done manually as I described above.

That sounds about as painful as parsing the ACPI MCFG table from scratch. Has anyone done this on seL4?

It'd be pretty useful if we had a program that could be run on a target platform during build time or as a one-off for a platform with a fixed hardware layout that could generate an FDT spec that could be fed back into camkes when producing a system image. As far as I'm aware this isn't roadmapped currently.

-- William Leslie

Q: What is your boss's password? A: "Authentication", clearly

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