From 95c7b0ad6c69d1c0608ff0bbd358a546856beaf3 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Mon, 29 Dec 2025 18:24:36 -0500 Subject: [PATCH] virtio_input: fix DMA alignment for evts 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 evts array is used for DMA_FROM_DEVICE operations via virtqueue_add_inbuf(). The adjacent lock and ready fields are written by the CPU during normal operation. If these share cachelines with evts, CPU writes can corrupt DMA data. Add __dma_from_device_group_begin()/end() annotations to ensure evts is isolated in its own cachelines. Message-ID: Signed-off-by: Michael S. Tsirkin --- drivers/virtio/virtio_input.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/virtio/virtio_input.c b/drivers/virtio/virtio_input.c index d0728285b6ce9..9f13de1f1d77b 100644 --- a/drivers/virtio/virtio_input.c +++ b/drivers/virtio/virtio_input.c @@ -4,6 +4,7 @@ #include #include #include +#include #include #include @@ -16,7 +17,9 @@ struct virtio_input { char serial[64]; char phys[64]; struct virtqueue *evt, *sts; + __dma_from_device_group_begin(); struct virtio_input_event evts[64]; + __dma_from_device_group_end(); spinlock_t lock; bool ready; }; -- 2.47.3