Commit 62d7f405 authored by Mina Almasry's avatar Mina Almasry Committed by Jakub Kicinski
Browse files

gve: support unreadable netmem 



Declare PP_FLAG_ALLOW_UNREADABLE_NETMEM to turn on unreadable netmem
support in GVE.

We also drop any net_iov packets where header split is not enabled.
We're unable to process packets where the header landed in unreadable
netmem.

Use page_pool_dma_sync_netmem_for_cpu in lieu of
dma_sync_single_range_for_cpu to correctly handle unreadable netmem
that should not be dma-sync'd.

Disable rx_copybreak optimization if payload is unreadable netmem as
that needs access to the payload.

Signed-off-by: default avatarMina Almasry <almasrymina@google.com>
Signed-off-by: default avatarZiwei Xiao <ziweixiao@google.com>
Signed-off-by: default avatarHarshitha Ramamurthy <hramamurthy@google.com>
Link: https://patch.msgid.link/20250818210507.3781705-1-hramamurthy@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent c3439666

drivers/net/ethernet/google/gve/gve_buffer_mgmt_dqo.c

+5 −0
Original line number Diff line number Diff line
@@ -260,6 +260,11 @@ struct page_pool *gve_rx_create_page_pool(struct gve_priv *priv, 
		.offset = xdp ? XDP_PACKET_HEADROOM : 0,

	};



	if (priv->header_split_enabled) {

		pp.flags |= PP_FLAG_ALLOW_UNREADABLE_NETMEM;

		pp.queue_idx = rx->q_num;

	}



	return page_pool_create(&pp);

}

drivers/net/ethernet/google/gve/gve_rx_dqo.c

+30 −5
Original line number Diff line number Diff line
@@ -718,6 +718,24 @@ static int gve_rx_xsk_dqo(struct napi_struct *napi, struct gve_rx_ring *rx, 
	return 0;

}



static void gve_dma_sync(struct gve_priv *priv, struct gve_rx_ring *rx,

			 struct gve_rx_buf_state_dqo *buf_state, u16 buf_len)

{

	struct gve_rx_slot_page_info *page_info = &buf_state->page_info;



	if (rx->dqo.page_pool) {

		page_pool_dma_sync_netmem_for_cpu(rx->dqo.page_pool,

						  page_info->netmem,

						  page_info->page_offset,

						  buf_len);

	} else {

		dma_sync_single_range_for_cpu(&priv->pdev->dev, buf_state->addr,

					      page_info->page_offset +

					      page_info->pad,

					      buf_len, DMA_FROM_DEVICE);

	}

}



/* Returns 0 if descriptor is completed successfully.

 * Returns -EINVAL if descriptor is invalid.

 * Returns -ENOMEM if data cannot be copied to skb.
@@ -793,13 +811,18 @@ static int gve_rx_dqo(struct napi_struct *napi, struct gve_rx_ring *rx, 
		rx->rx_hsplit_unsplit_pkt += unsplit;

		rx->rx_hsplit_bytes += hdr_len;

		u64_stats_update_end(&rx->statss);

	} else if (!rx->ctx.skb_head && rx->dqo.page_pool &&

		   netmem_is_net_iov(buf_state->page_info.netmem)) {

		/* when header split is disabled, the header went to the packet

		 * buffer. If the packet buffer is a net_iov, those can't be

		 * easily mapped into the kernel space to access the header

		 * required to process the packet.

		 */

		goto error;

	}



	/* Sync the portion of dma buffer for CPU to read. */

	dma_sync_single_range_for_cpu(&priv->pdev->dev, buf_state->addr,

				      buf_state->page_info.page_offset +

				      buf_state->page_info.pad,

				      buf_len, DMA_FROM_DEVICE);

	gve_dma_sync(priv, rx, buf_state, buf_len);



	/* Append to current skb if one exists. */

	if (rx->ctx.skb_head) {
@@ -837,7 +860,9 @@ static int gve_rx_dqo(struct napi_struct *napi, struct gve_rx_ring *rx, 
		u64_stats_update_end(&rx->statss);

	}



	if (eop && buf_len <= priv->rx_copybreak) {

	if (eop && buf_len <= priv->rx_copybreak &&

	    !(rx->dqo.page_pool &&

	      netmem_is_net_iov(buf_state->page_info.netmem))) {

		rx->ctx.skb_head = gve_rx_copy(priv->dev, napi,

					       &buf_state->page_info, buf_len);

		if (unlikely(!rx->ctx.skb_head))