[PATCH v2 08/15] vsock/virtio: use virtqueue_add_inbuf_cache_clean for events

Michael S. Tsirkin
2026-01-05T08:23:28Z

The event_list array contains 8 small (4-byte) events that share
cachelines with each other. When CONFIG_DMA_API_DEBUG is enabled,
this can trigger warnings about overlapping DMA mappings within
the same cacheline.

The previous patch isolated event_list in its own cache lines
so the warnings are spurious.

Use virtqueue_add_inbuf_cache_clean() to indicate that the CPU does not
write into these fields, suppressing the warnings.

Reported-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
net/vmw_vsock/virtio_transport.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index bb94baadfd8b..ef983c36cb66 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -392,7 +392,7 @@ static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,

sg_init_one(&sg, event, sizeof(*event));

- return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
+ return virtqueue_add_inbuf_cache_clean(vq, &sg, 1, event, GFP_KERNEL);
}

/* event_lock must be held */
--
MST