gve: Fixes DMA synchronization.

Synces the DMA buffer properly in order for CPU and device to see
the most up-to-data data.

Signed-off-by: Yangchun Fu <yangchun@google.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/google/gve/gve_rx.c b/drivers/net/ethernet/google/gve/gve_rx.c
index 59564ac..edec61d 100644 (file)
--- a/drivers/net/ethernet/google/gve/gve_rx.c
+++ b/drivers/net/ethernet/google/gve/gve_rx.c
@@ -289,6 +289,8 @@ static bool gve_rx(struct gve_rx_ring *rx, struct gve_rx_desc *rx_desc,
 
        len = be16_to_cpu(rx_desc->len) - GVE_RX_PAD;
        page_info = &rx->data.page_info[idx];
+       dma_sync_single_for_cpu(&priv->pdev->dev, rx->data.qpl->page_buses[idx],
+                               PAGE_SIZE, DMA_FROM_DEVICE);
 
        /* gvnic can only receive into registered segments. If the buffer
         * can't be recycled, our only choice is to copy the data out of

diff --git a/drivers/net/ethernet/google/gve/gve_tx.c b/drivers/net/ethernet/google/gve/gve_tx.c
index 778b87b..0a9a7ee 100644 (file)
--- a/drivers/net/ethernet/google/gve/gve_tx.c
+++ b/drivers/net/ethernet/google/gve/gve_tx.c
@@ -390,7 +390,21 @@ static void gve_tx_fill_seg_desc(union gve_tx_desc *seg_desc,
        seg_desc->seg.seg_addr = cpu_to_be64(addr);
 }
 
-static int gve_tx_add_skb(struct gve_tx_ring *tx, struct sk_buff *skb)
+static void gve_dma_sync_for_device(struct device *dev, dma_addr_t *page_buses,
+                                   u64 iov_offset, u64 iov_len)
+{
+       dma_addr_t dma;
+       u64 addr;
+
+       for (addr = iov_offset; addr < iov_offset + iov_len;
+            addr += PAGE_SIZE) {
+               dma = page_buses[addr / PAGE_SIZE];
+               dma_sync_single_for_device(dev, dma, PAGE_SIZE, DMA_TO_DEVICE);
+       }
+}
+
+static int gve_tx_add_skb(struct gve_tx_ring *tx, struct sk_buff *skb,
+                         struct device *dev)
 {
        int pad_bytes, hlen, hdr_nfrags, payload_nfrags, l4_hdr_offset;
        union gve_tx_desc *pkt_desc, *seg_desc;
@@ -432,6 +446,9 @@ static int gve_tx_add_skb(struct gve_tx_ring *tx, struct sk_buff *skb)
        skb_copy_bits(skb, 0,
                      tx->tx_fifo.base + info->iov[hdr_nfrags - 1].iov_offset,
                      hlen);
+       gve_dma_sync_for_device(dev, tx->tx_fifo.qpl->page_buses,
+                               info->iov[hdr_nfrags - 1].iov_offset,
+                               info->iov[hdr_nfrags - 1].iov_len);
        copy_offset = hlen;
 
        for (i = payload_iov; i < payload_nfrags + payload_iov; i++) {
@@ -445,6 +462,9 @@ static int gve_tx_add_skb(struct gve_tx_ring *tx, struct sk_buff *skb)
                skb_copy_bits(skb, copy_offset,
                              tx->tx_fifo.base + info->iov[i].iov_offset,
                              info->iov[i].iov_len);
+               gve_dma_sync_for_device(dev, tx->tx_fifo.qpl->page_buses,
+                                       info->iov[i].iov_offset,
+                                       info->iov[i].iov_len);
                copy_offset += info->iov[i].iov_len;
        }
 
@@ -473,7 +493,7 @@ netdev_tx_t gve_tx(struct sk_buff *skb, struct net_device *dev)
                gve_tx_put_doorbell(priv, tx->q_resources, tx->req);
                return NETDEV_TX_BUSY;
        }
-       nsegs = gve_tx_add_skb(tx, skb);
+       nsegs = gve_tx_add_skb(tx, skb, &priv->pdev->dev);
 
        netdev_tx_sent_queue(tx->netdev_txq, skb->len);
        skb_tx_timestamp(skb);