Passthrough not working with OpenBSD nor NetBSD
John Baldwin
jhb at FreeBSD.org
Thu Aug 9 17:30:08 UTC 2018
They may implement INTx interrupts for pass-through perhaps. INTx are a
lot bigger pain to emulate since there isn't a standard way in PCI to
determine if an interrupt is pending (and you need that to simulate a
level-triggered interrupt like INTx). I think very recent revisions of
PCI did add a new bit to test that in the PCI status register, but it is
in a new enough version of PCI that any compliant devices would also support
MSI anyway.
On 8/9/18 10:07 AM, Farid Joubbi wrote:
> How does KVM and VMware solve that?
> I haven't tried PCI passthrough with them, but I assume that it works..?
>
> On Thu, Aug 9, 2018, 18:24 John Baldwin <jhb at freebsd.org <mailto:jhb at freebsd.org>> wrote:
>
> On 8/8/18 11:08 AM, Farid Joubbi wrote:
> > That's what I also thought, but it's not anything I can force it to do, is it? Isn't it supposed to detect the MSI interrupt compatibility automatically?
>
> Apparently Open/Net always try to setup INTx before trying MSI even if they
> won't use INTx per the commit log in revision 280725. We could perhaps try
> to provide a "fake" INTx interrupt that doesn't work, but I'll have to think
> about how to implement that.
>
> --
> John Baldwin
>
--
John Baldwin
More information about the freebsd-virtualization
mailing list