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[80.230.31.118]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-47d193d4e91sm569777955e9.13.2025.12.30.02.16.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Dec 2025 02:16:09 -0800 (PST) Date: Tue, 30 Dec 2025 05:16:07 -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 07/13] vsock/virtio: fix DMA alignment for event_list Message-ID: References: Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent On non-cache-coherent platforms, when a structure contains a buffer used for DMA alongside fields that the CPU writes to, cacheline sharing can cause data corruption. The event_list array is used for DMA_FROM_DEVICE operations via virtqueue_add_inbuf(). The adjacent event_run and guest_cid fields are written by the CPU while the buffer is available, so mapped for the device. If these share cachelines with event_list, CPU writes can corrupt DMA data. Add __dma_from_device_aligned_begin/end annotations to ensure event_list is isolated in its own cachelines. Signed-off-by: Michael S. Tsirkin --- net/vmw_vsock/virtio_transport.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index 8c867023a2e5..76099f7dc040 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include #include @@ -59,8 +60,10 @@ struct virtio_vsock { */ struct mutex event_lock; bool event_run; + __dma_from_device_aligned_begin struct virtio_vsock_event event_list[8]; + __dma_from_device_aligned_end u32 guest_cid; bool seqpacket_allow; -- MST