Re: Inquiry About PCI Passthrough Development and Testing Patches on ARM

[Mykyta Poturai <Mykyta_Poturai@xxxxxxxx>]

Hi Shenghui,
I have somewhat taken over the upstreaming effort for now, here is our plan:
- 2025 Q1
        1. Send "xen/arm: platform: Add support for R-Car Gen4" - Done
        2. Revive "SMMU handling for PCIe Passthrough on ARM" - Done
        3. Send "Add support for R-Car Gen4 PCIE Host"
        4. Revive "PCI devices passthrough on Arm, part 3"
- 2025 Q2
        1. Send "IPMMU handling for PCIe Passthrough"
        2. Send "Enable the existing MSI-X and MSI handlers support for ARM"
        3. Revive  "Kconfig for PCI passthrough on ARM"
        4. Send "PCI devices passthrough on Arm, part 4(pci scan support)"

Please note that most Q2 patches depend on Q1 patches in some way, so it 
may require waiting some more time if the review process takes a long time.

There are downstream WIP branches 
https://github.com/Deedone/xen/tree/pci_passthrough_wip (based on 
4.20-rc3), 
https://gitlab.com/xen-project/people/bmarquis/xen-arm-poc/-/commits/poc/pci-passthrough
 
(based on 4.17-unstable) that currently have PCI passthrough working on 
Arm, but on upstream it is not yet functional. There is also work done 
on moving PCI host from hardware domain to a separate driver domain, but 
it is very WIP and not yet ready to be upstreamed.

-- 
Mykyta

On 14.02.25 12:55, shenghui qu wrote:
> Dear Stewart
> 
> Thank you for being looped into this discussion.
> Following Stefano’s guidance, I’d like to seek further clarity on the 
> current development of PCI Passthrough support for Xen/ARM.
> Specifically, I have two questions:
> 1.Roadmap: Are there clear milestones or a timeline for completing PCI 
> Passthrough support on ARM? For instance, is this feature targeted for 
> inclusion in Xen 4.20 or later releases？
> 2.Current Status: Could you elaborate on the technical progress so far?
> 
> Looking forward to your insights.
> 
> Best regards,
> Shenghui Qu
> 
> Stefano Stabellini <sstabellini@xxxxxxxxxx 
> <mailto:sstabellini@xxxxxxxxxx>> 于2025年2月14日周五 04:14写道：
> 
>     Hi Shenghui,
> 
>     Thank you for your interest in Xen! Let me add Stewart, who can provide
>     you with an overview of the latest status of PCI Passthrough on ARM.
> 
>     Among the various items in progress, I would like to highlight this
>     series from Mykyta, which is currently under review:
> 
>     https://marc.info/?l=xen-devel&m=173918318831281
> 
>     Cheers,
> 
>     Stefano
> 
>     On Thu, 13 Feb 2025, shenghui qu wrote:
>      > Dear Maintainers,
>      >
>      > I hope this email finds you well.
>      >
>      > I recently came across the Xen Project 4.19 Feature List, which
>     mentions that PCI passthrough work on ARM is ongoing, including some
>      > refactoring and improvements of the existing code. It also states
>     that this work will be included in the next few releases.
>      > I am very interested in the current development plan and progress
>     of PCI passthrough on ARM. Could you kindly provide an update on this?
>      >
>      > Additionally, I would like to know how I can access any available
>     testing patches related to this work.
>      >
>      > I appreciate your time and effort in maintaining and improving
>     the Xen Project. Looking forward to your response.
>      >
>      > Best regards,Shenghui Qu
>      >
>      >