Re: [PATCH v3 0/2] block: Enable proper MMIO memory handling for P2P DMA

Leon Romanovsky
2025-11-09T07:53:46Z

On Mon, Oct 27, 2025 at 09:30:19AM +0200, Leon Romanovsky wrote:

<...>

> ----------------------------------------------------------------------
>
> This patch series improves block layer and NVMe driver support for MMIO
> memory regions, particularly for peer-to-peer (P2P) DMA transfers that
> go through the host bridge.
>
> The series addresses a critical gap where P2P transfers through the host
> bridge (PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) were not properly marked as
> MMIO memory, leading to potential issues with:
>
> - Inappropriate CPU cache synchronization operations on MMIO regions
> - Incorrect DMA mapping/unmapping that doesn't respect MMIO semantics
> - Missing IOMMU configuration for MMIO memory handling
>
> This work is extracted from the larger DMA physical API improvement
> series [1] and focuses specifically on block layer and NVMe requirements
> for MMIO memory support.
>
> Thanks
>
> [1] https://lore.kernel.org/all/cover.1757423202.git.leonro@nvidia.com/
>
> Leon Romanovsky (2):
> nvme-pci: migrate to dma_map_phys instead of map_page
> block-dma: properly take MMIO path

Hi,

Kind reminder.

Thanks