[23.10 FEAT] [VS2111] KVM: Enhance CCW address translation architectural compliance

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Currently, CCW passthrough relies on every I/O containing only direct-addressed CCWs or a 4K Format-2 IDA, which is sufficient for Linux. Other operating systems may however require different formats and can fail on I/O.

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------- Comment From <email address hidden> 2023-07-05 18:00 EDT-------
Update by ERIC R. FARMAN:
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The entirety of the vfio space has gone through a lot of rework in recent releases, though the commits in question for this item are specific to vfio-ccw and went in during the v6.3 merge window. I'll annotate the list because some are not strictly necessary:

$ git log --oneline v6.2..v6.3-rc1 -- drivers/s390/cio/vfio_ccw_*
# 1c06bb87afb2 vfio/ccw: remove WARN_ON during shutdown
# Not needed; fix to a patch that went in 6.2 (and backported to 6.2.3)
beb060ed20d5 vfio/ccw: remove old IDA format restrictions
b5a73e8eb225 vfio/ccw: don't group contiguous pages on 2K IDAWs
# Optional; dependent on commit cfedb3d5e602 ("vfio/ccw: Only pass in contiguous pages")
1b676fe3d9d3 vfio/ccw: handle a guest Format-1 IDAL
61f3a16b9d5c vfio/ccw: allocate/populate the guest idal
6a6dc14ac847 vfio/ccw: calculate number of IDAWs regardless of format
667e5dbabf2b vfio/ccw: read only one Format-1 IDAW
b21f9cb1124e vfio/ccw: refactor the idaw counter
61783394f4eb vfio/ccw: populate page_array struct inline
62a97a56a64c vfio/ccw: pass page count to page_array struct
4b946d65b8aa vfio/ccw: remove unnecessary malloc alignment
# Optional; was opportunistic cleanup, can leave as-is
a4c6040472ba vfio/ccw: simplify CCW chain fetch routines
c5e8083f9580 vfio/ccw: replace copy_from_iova with vfio_dma_rw
# Optional;
# Interface was introduced in commit 8d46c0cca5f4 ("vfio: introduce vfio_dma_rw to read/write a range of IOVAs").
# Because of commit c6250ffbacc5 ("vfio/mdev: Pass in a struct vfio_device * to vfio_dma_rw()"),
# this may depend on commit 3bf1311f351e ("vfio/ccw: Convert to use vfio_register_emulated_iommu_dev()")
254cb663c2ac vfio/ccw: move where IDA flag is set in ORB
155a4321c117 vfio/ccw: allow non-zero storage keys
# 9fbed59fcd16 vfio/ccw: simplify the cp_get_orb interface
# Not needed; suggestion from review of a 6.2 patch
# 8a54e238ef1e vfio/ccw: cleanup some of the mdev commentary
# Not needed; comment cleanup from 6.2

Since these IDA formats are 2K-aligned, the above relies on the core vfio interface for vfio_pin_pages and vfio_unpin_pages using a list of struct pages (e.g., see [1] and [2]), instead of PFNs. With the original PFN-based interface, an alternative would be needed to track the page offset information when re-constituting the translated addresses before issuing an I/O. I have one squirreled away that I could provide, if it would help alleviate the drag on other drivers.

[1] commit 34a255e67615 ("vfio: Replace phys_pfn with pages for vfio_pin_pages()")
[2] commit 1331460514ff ("vfio/ccw: Change pa_pfn list to pa_iova list")

[Frank Heimes (fheimes)]

I've verified if the commits listed in comment #1 are incl. in current mantic master-next and they are, incl. all optional and suggested ones.
And since we already have a linux-generic kernel 6.3 in mantic:
 linux-generic | 6.3.0.7.8 | mantic | amd64, arm64, armhf, ppc64el, s390x
 linux-generic | 6.3.0.7.9 | mantic-proposed | amd64, arm64, armhf, ppc64el, s390x

I'm updating this ticket to Fix Released.