[PATCH RFC 08/13] vsock/virtio: use virtqueue_add_inbuf_cache_clean for events
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2025-12-30 10:16:18
Also in:
kvm, linux-crypto, linux-doc, linux-iommu, linux-scsi, lkml, virtualization
Subsystem:
networking [general], the rest, virtio and vhost vsock driver, virtio core, vm sockets (af_vsock) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Stefan Hajnoczi, Stefano Garzarella, "Michael S. Tsirkin", Jason Wang
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 <redacted> 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 76099f7dc040..f1589db5d190 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c@@ -393,7 +393,7 @@ 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 */
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MST