Public bug reported:

Summary:

This PR is to cherrypick/backport the following core feature series from 
upstream to linux-nvidia-6.17
These core series includes:

A.      DMA_ATTR_MMIO that allows for MMIO region mapping -
https://lore.kernel.org/all/[email protected]/

B.      Convert  {.map_page/.map_resource/.unmap_page/.unmap_resource}
callbacks to new .map_phys/.unmap_phys interfaces -
https://lore.kernel.org/all/20251015-remove-map-
[email protected]/

C.      VFIO/PCI to VFIO PCI subsystem to support exporting MMIO regions
from PCI device BARs as dma-buf objects -
https://lore.kernel.org/all/20251120-dmabuf-
[email protected]/


In order to get all the above core feature series into linux-nvidia-6.17, I 
have to bring in more intermediate changes for block/nvme and virtio/vhost.
To cherry pick the patches cleanly and avoid bugs during backporting process, I 
applied patches in the order as they appeared upstream.
Here is the detail that can help in review process:

1. Pick patch series ‘A’ DMA_ATTR_MMIO - 
https://lore.kernel.org/all/[email protected]/
Even though the patch series shows 16 patches, like upstream kernel I first 
apply only 13 patches.
The remaining 3 are block/nvme changes that requires other changes before they 
go in.

2. In order to bring block/nvme changes for ‘A’ we need to:
2.1 Revert existing patch “NVIDIA: SAUCE: Patch NVMe/NVMeoF driver to support 
GDS on Linux 6.17 Kernel”
2.2 Apply patch block/nvme series  - 
https://lore.kernel.org/all/[email protected]/ 
2.3 Pick upstream commit 0d2d0c437b ("blk-mq-dma: bring back p2p request flags")
2.4 Apply the remaining block/nvme changes from series ‘A’ aka DMA_ATTR_MMIO.
Note that only 2 patches are added upstream. Meaning the 3 patches are 
re-factored into 2 patches.
e.g.
block-dma: properly take MMIO path
nvme-pci: migrate to dma_map_phys instead of map_page

2.5 re-revert / backport “NVIDIA: SAUCE: Patch NVMe/NVMeoF driver to
support GDS on Linux 6.17 Kernel”

3.  Before bringing in the core patch series B, bring in virtio/vduse changes 
to avoid compile error with dma_map functions.
3.1 Bring all missing virtio/vhost changes from upstream merge commit 
bf897d2626abe4559953342e2f7dda05d034c8c7

4. Apply the last VFIO/PCI series ‘C’


Testing:
This has been tested on GB300 with 'GPUDirect RDAM w/ data-direct' where GPU 
driver uses 'dma_buf_phys_vec_to_sgt()' to check it can talk to peer device 
(CX8) directly or via Host PCI Bridge.

** Affects: linux-nvidia (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/2139370

Title:
  Backport DMA_ATTR_MMIO and VFIO/PCI to export MMIO region as DMA-Buf
  series from upstream

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