[PATCH AUTOSEL 6.6 75/83] virtio_ring: fix KMSAN error for premapped mode

[Sasha Levin]

From: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>

[ Upstream commit 840b2d39a2dc1b96deb3f5c7fef76c9b24f08f51 ]

Add kmsan for virtqueue_dma_map_single_attrs to fix:

BUG: KMSAN: uninit-value in receive_buf+0x45ca/0x6990
 receive_buf+0x45ca/0x6990
 virtnet_poll+0x17e0/0x3130
 net_rx_action+0x832/0x26e0
 handle_softirqs+0x330/0x10f0
 [...]

Uninit was created at:
 __alloc_pages_noprof+0x62a/0xe60
 alloc_pages_noprof+0x392/0x830
 skb_page_frag_refill+0x21a/0x5c0
 virtnet_rq_alloc+0x50/0x1500
 try_fill_recv+0x372/0x54c0
 virtnet_open+0x210/0xbe0
 __dev_open+0x56e/0x920
 __dev_change_flags+0x39c/0x2000
 dev_change_flags+0xaa/0x200
 do_setlink+0x197a/0x7420
 rtnl_setlink+0x77c/0x860
 [...]

Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
Tested-by: Alexander Potapenko <glider@xxxxxxxxxx>
Message-Id: <20240606111345.93600-1-xuanzhuo@xxxxxxxxxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Tested-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>  # s390x
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/virtio/virtio_ring.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 6f7e5010a6735..80669e05bf0ee 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -3126,8 +3126,10 @@ dma_addr_t virtqueue_dma_map_single_attrs(struct virtqueue *_vq, void *ptr,
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
 
-	if (!vq->use_dma_api)
+	if (!vq->use_dma_api) {
+		kmsan_handle_dma(virt_to_page(ptr), offset_in_page(ptr), size, dir);
 		return (dma_addr_t)virt_to_phys(ptr);
+	}
 
 	return dma_map_single_attrs(vring_dma_dev(vq), ptr, size, dir, attrs);
 }
-- 
2.43.0