Re: [RFC 00/12] PCI: Add support for Scalable I/O Virtualization

[Dimitri Daskalakis <dimitri.daskalakis1@gmail.com>]

On 6/4/26 11:20 AM, Jason Gunthorpe wrote:
> On Thu, Jun 04, 2026 at 08:01:41AM -0700, Dimitri Daskalakis wrote:
>> With this patchset core enumarates the SIOV capability and can identify
>> SIOV PFs. But there is no central mechanism to allocate/manage SIOV VFs.
>> To support device pass through, devices will need to add a vfio-mdev
>> driver with IOMMUFD support (or something similar).
> 
> There is an enormous amount of missing work to do something useful
> with the SIOVr2 stuff. IIRC there is even supposed to be BIOS
> components in this plan and there are some missing PCI SIG topics too
> IIRC.
> 
> So, I'm not sure how much value there is in merging just the cap
> discovery without a roadmap for the missing parts..
> 
> Also, I'm quite surprised to see this out of the blue, there is an OCP
> workstream that was building out a standard that outlines how all the
> different components have to act to successfully implement it.  What
> is in PCI SIG was just some minor foundational adjustments without any
> context on how to form them into a solution.
> 
> I think it is extremely premature to merge anything related to SIOV to
> the kernel. Join the OCP work stream if you are interested. I think
> the general feeling was there is not sufficient interest in the
> industry to do this and it has gone quiet.
> 
> Jason

Hey Jason, thanks for the feedback. We (at Meta) are definitely
interested in SIOV-like capabilities for device passthrough to containers.

For those scenarios, having PCIe transactions per RID plus IOMMU
isolation is enough, but I can imagine hypervisors/VMs requiring more
platform support.

I hear you on the broader support story being premature. But on the
other hand, this series unblocks experimentation at the driver level
for basic data path validation.