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Re: VirtIO MMIO for amd64




On 12/19/23 13:11, Taylor R Campbell wrote:

to queue a task and then run it.  Normally softint_schedule is called
from a hard interrupt handler.  Here, you need something in the host
to get hard interrupts.

For example, on ACPI systems there are ACPI interrupt resources that
can be used with acpi_intr_establish; on FDT systems, device nodes
have interrupt properties that can be used with fdtbus_intr_establish.

How does FreeBSD get x86 mmio intrs on these systems?

Well that's the thing, I can't find where does MMIO attaches on FreeBSD,
they have a very simple way of creating the resources:

https://github.com/freebsd/freebsd-src/blob/main/sys/dev/virtio/mmio/virtio_mmio_cmdline.c#L109

and even Colin doesn't know where this goes https://x.com/cperciva/status/1737208888959840762?s=20

What I can say: it's not ACPI nor PCI as they are both unsupported
on Firecracker.

--
------------------------------------------------------------------------
Emile `iMil' Heitor <imil@{home.imil.net,NetBSD.org}> | https://imil.net


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