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[80.230.31.118]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4324e9ba877sm67681523f8f.0.2025.12.30.02.15.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Dec 2025 02:15:45 -0800 (PST) Date: Tue, 30 Dec 2025 05:15:42 -0500 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Cong Wang , Jonathan Corbet , Olivia Mackall , Herbert Xu , Jason Wang , Paolo Bonzini , Stefan Hajnoczi , Eugenio =?utf-8?B?UMOpcmV6?= , "James E.J. Bottomley" , "Martin K. Petersen" , Gerd Hoffmann , Xuan Zhuo , Marek Szyprowski , Robin Murphy , Stefano Garzarella , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Petr Tesarik , Leon Romanovsky , Jason Gunthorpe , linux-doc@vger.kernel.org, linux-crypto@vger.kernel.org, virtualization@lists.linux.dev, linux-scsi@vger.kernel.org, iommu@lists.linux.dev, kvm@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH RFC 00/13] fix DMA aligment issues around virtio Message-ID: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent Cong Wang reported dma debug warnings with virtio-vsock and proposed a patch, see: https://lore.kernel.org/all/20251228015451.1253271-1-xiyou.wangcong@gmail.com/ however, the issue is more widespread. This is an attempt to fix it systematically. Note: i2c and gio might also be affected, I am still looking into it. Help from maintainers welcome. Early RFC, compile tested only. Sending for early feedback/flames. Cursor/claude used liberally mostly for refactoring, and english. DMA maintainers, could you please confirm the DMA core changes are ok with you? Thanks! Michael S. Tsirkin (13): dma-mapping: add __dma_from_device_align_begin/end docs: dma-api: document __dma_align_begin/end dma-mapping: add DMA_ATTR_CPU_CACHE_CLEAN docs: dma-api: document DMA_ATTR_CPU_CACHE_CLEAN dma-debug: track cache clean flag in entries virtio: add virtqueue_add_inbuf_cache_clean API vsock/virtio: fix DMA alignment for event_list vsock/virtio: use virtqueue_add_inbuf_cache_clean for events virtio_input: fix DMA alignment for evts virtio_scsi: fix DMA cacheline issues for events virtio-rng: fix DMA alignment for data buffer virtio_input: use virtqueue_add_inbuf_cache_clean for events vsock/virtio: reorder fields to reduce struct padding Documentation/core-api/dma-api-howto.rst | 42 +++++++++++++ Documentation/core-api/dma-attributes.rst | 9 +++ drivers/char/hw_random/virtio-rng.c | 2 + drivers/scsi/virtio_scsi.c | 18 ++++-- drivers/virtio/virtio_input.c | 5 +- drivers/virtio/virtio_ring.c | 72 +++++++++++++++++------ include/linux/dma-mapping.h | 17 ++++++ include/linux/virtio.h | 5 ++ kernel/dma/debug.c | 26 ++++++-- net/vmw_vsock/virtio_transport.c | 8 ++- 10 files changed, 172 insertions(+), 32 deletions(-) -- MST