[PATCH v4 0/2] block: Enable proper MMIO memory handling for P2P DMA

Jens Axboe axboe at kernel.dk
Thu Nov 13 09:12:41 PST 2025


On 11/13/25 9:39 AM, Jens Axboe wrote:
> 
> On Wed, 12 Nov 2025 21:48:03 +0200, Leon Romanovsky wrote:
>> Changelog:
>> v4:
>>  * Changed double "if" to be "else if".
>>  * Added missed PCI_P2PDMA_MAP_NONE case.
>> v3: https://patch.msgid.link/20251027-block-with-mmio-v3-0-ac3370e1f7b7@nvidia.com
>>  * Encoded p2p map type in IOD flags instead of DMA attributes.
>>  * Removed REQ_P2PDMA flag from block layer.
>>  * Simplified map_phys conversion patch.
>> v2: https://lore.kernel.org/all/20251020-block-with-mmio-v2-0-147e9f93d8d4@nvidia.com/
>>  * Added Chirstoph's Reviewed-by tag for first patch.
>>  * Squashed patches
>>  * Stored DMA MMIO attribute in NVMe IOD flags variable instead of block layer.
>> v1: https://patch.msgid.link/20251017-block-with-mmio-v1-0-3f486904db5e@nvidia.com
>>  * Reordered patches.
>>  * Dropped patch which tried to unify unmap flow.
>>  * Set MMIO flag separately for data and integrity payloads.
>> v0: https://lore.kernel.org/all/cover.1760369219.git.leon@kernel.org/
>>
>> [...]
> 
> Applied, thanks!
> 
> [1/2] nvme-pci: migrate to dma_map_phys instead of map_page
>       commit: f10000db2f7cf29d8c2ade69266bed7b51c772cb
> [2/2] block-dma: properly take MMIO path
>       commit: 8df2745e8b23fdbe34c5b0a24607f5aaf10ed7eb

And now dropped again - this doesn't boot on neither my big test box
with 33 nvme drives, nor even on my local test vm. Two different archs,
and very different setups. Which begs the question, how on earth was
this tested, if it doesn't boot on anything I have here?!

-- 
Jens Axboe



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