1 files changed, 446 insertions, 0 deletions
diff --git a/drivers/net/ethernet/google/gve/gve_rx.c b/drivers/net/ethernet/google/gve/gve_rx.c
new file mode 100644
index 000000000000..1914b8350da7
--- /dev/null
+++ b/drivers/net/ethernet/google/gve/gve_rx.c
@@ -0,0 +1,446 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/* Google virtual Ethernet (gve) driver
+ *
+ * Copyright (C) 2015-2019 Google, Inc.
+ */
+
+#include "gve.h"
+#include "gve_adminq.h"
+#include <linux/etherdevice.h>
+
+static void gve_rx_remove_from_block(struct gve_priv *priv, int queue_idx)
+{
+	struct gve_notify_block *block =
+			&priv->ntfy_blocks[gve_rx_idx_to_ntfy(priv, queue_idx)];
+
+	block->rx = NULL;
+}
+
+static void gve_rx_free_ring(struct gve_priv *priv, int idx)
+{
+	struct gve_rx_ring *rx = &priv->rx[idx];
+	struct device *dev = &priv->pdev->dev;
+	size_t bytes;
+	u32 slots;
+
+	gve_rx_remove_from_block(priv, idx);
+
+	bytes = sizeof(struct gve_rx_desc) * priv->rx_desc_cnt;
+	dma_free_coherent(dev, bytes, rx->desc.desc_ring, rx->desc.bus);
+	rx->desc.desc_ring = NULL;
+
+	dma_free_coherent(dev, sizeof(*rx->q_resources),
+			  rx->q_resources, rx->q_resources_bus);
+	rx->q_resources = NULL;
+
+	gve_unassign_qpl(priv, rx->data.qpl->id);
+	rx->data.qpl = NULL;
+	kvfree(rx->data.page_info);
+
+	slots = rx->data.mask + 1;
+	bytes = sizeof(*rx->data.data_ring) * slots;
+	dma_free_coherent(dev, bytes, rx->data.data_ring,
+			  rx->data.data_bus);
+	rx->data.data_ring = NULL;
+	netif_dbg(priv, drv, priv->dev, "freed rx ring %d\n", idx);
+}
+
+static void gve_setup_rx_buffer(struct gve_rx_slot_page_info *page_info,
+				struct gve_rx_data_slot *slot,
+				dma_addr_t addr, struct page *page)
+{
+	page_info->page = page;
+	page_info->page_offset = 0;
+	page_info->page_address = page_address(page);
+	slot->qpl_offset = cpu_to_be64(addr);
+}
+
+static int gve_prefill_rx_pages(struct gve_rx_ring *rx)
+{
+	struct gve_priv *priv = rx->gve;
+	u32 slots;
+	int i;
+
+	/* Allocate one page per Rx queue slot. Each page is split into two
+	 * packet buffers, when possible we "page flip" between the two.
+	 */
+	slots = rx->data.mask + 1;
+
+	rx->data.page_info = kvzalloc(slots *
+				      sizeof(*rx->data.page_info), GFP_KERNEL);
+	if (!rx->data.page_info)
+		return -ENOMEM;
+
+	rx->data.qpl = gve_assign_rx_qpl(priv);
+
+	for (i = 0; i < slots; i++) {
+		struct page *page = rx->data.qpl->pages[i];
+		dma_addr_t addr = i * PAGE_SIZE;
+
+		gve_setup_rx_buffer(&rx->data.page_info[i],
+				    &rx->data.data_ring[i], addr, page);
+	}
+
+	return slots;
+}
+
+static void gve_rx_add_to_block(struct gve_priv *priv, int queue_idx)
+{
+	u32 ntfy_idx = gve_rx_idx_to_ntfy(priv, queue_idx);
+	struct gve_notify_block *block = &priv->ntfy_blocks[ntfy_idx];
+	struct gve_rx_ring *rx = &priv->rx[queue_idx];
+
+	block->rx = rx;
+	rx->ntfy_id = ntfy_idx;
+}
+
+static int gve_rx_alloc_ring(struct gve_priv *priv, int idx)
+{
+	struct gve_rx_ring *rx = &priv->rx[idx];
+	struct device *hdev = &priv->pdev->dev;
+	u32 slots, npages;
+	int filled_pages;
+	size_t bytes;
+	int err;
+
+	netif_dbg(priv, drv, priv->dev, "allocating rx ring\n");
+	/* Make sure everything is zeroed to start with */
+	memset(rx, 0, sizeof(*rx));
+
+	rx->gve = priv;
+	rx->q_num = idx;
+
+	slots = priv->rx_pages_per_qpl;
+	rx->data.mask = slots - 1;
+
+	/* alloc rx data ring */
+	bytes = sizeof(*rx->data.data_ring) * slots;
+	rx->data.data_ring = dma_alloc_coherent(hdev, bytes,
+						&rx->data.data_bus,
+						GFP_KERNEL);
+	if (!rx->data.data_ring)
+		return -ENOMEM;
+	filled_pages = gve_prefill_rx_pages(rx);
+	if (filled_pages < 0) {
+		err = -ENOMEM;
+		goto abort_with_slots;
+	}
+	rx->desc.fill_cnt = filled_pages;
+	/* Ensure data ring slots (packet buffers) are visible. */
+	dma_wmb();
+
+	/* Alloc gve_queue_resources */
+	rx->q_resources =
+		dma_alloc_coherent(hdev,
+				   sizeof(*rx->q_resources),
+				   &rx->q_resources_bus,
+				   GFP_KERNEL);
+	if (!rx->q_resources) {
+		err = -ENOMEM;
+		goto abort_filled;
+	}
+	netif_dbg(priv, drv, priv->dev, "rx[%d]->data.data_bus=%lx\n", idx,
+		  (unsigned long)rx->data.data_bus);
+
+	/* alloc rx desc ring */
+	bytes = sizeof(struct gve_rx_desc) * priv->rx_desc_cnt;
+	npages = bytes / PAGE_SIZE;
+	if (npages * PAGE_SIZE != bytes) {
+		err = -EIO;
+		goto abort_with_q_resources;
+	}
+
+	rx->desc.desc_ring = dma_alloc_coherent(hdev, bytes, &rx->desc.bus,
+						GFP_KERNEL);
+	if (!rx->desc.desc_ring) {
+		err = -ENOMEM;
+		goto abort_with_q_resources;
+	}
+	rx->desc.mask = slots - 1;
+	rx->desc.cnt = 0;
+	rx->desc.seqno = 1;
+	gve_rx_add_to_block(priv, idx);
+
+	return 0;
+
+abort_with_q_resources:
+	dma_free_coherent(hdev, sizeof(*rx->q_resources),
+			  rx->q_resources, rx->q_resources_bus);
+	rx->q_resources = NULL;
+abort_filled:
+	kvfree(rx->data.page_info);
+abort_with_slots:
+	bytes = sizeof(*rx->data.data_ring) * slots;
+	dma_free_coherent(hdev, bytes, rx->data.data_ring, rx->data.data_bus);
+	rx->data.data_ring = NULL;
+
+	return err;
+}
+
+int gve_rx_alloc_rings(struct gve_priv *priv)
+{
+	int err = 0;
+	int i;
+
+	for (i = 0; i < priv->rx_cfg.num_queues; i++) {
+		err = gve_rx_alloc_ring(priv, i);
+		if (err) {
+			netif_err(priv, drv, priv->dev,
+				  "Failed to alloc rx ring=%d: err=%d\n",
+				  i, err);
+			break;
+		}
+	}
+	/* Unallocate if there was an error */
+	if (err) {
+		int j;
+
+		for (j = 0; j < i; j++)
+			gve_rx_free_ring(priv, j);
+	}
+	return err;
+}
+
+void gve_rx_free_rings(struct gve_priv *priv)
+{
+	int i;
+
+	for (i = 0; i < priv->rx_cfg.num_queues; i++)
+		gve_rx_free_ring(priv, i);
+}
+
+void gve_rx_write_doorbell(struct gve_priv *priv, struct gve_rx_ring *rx)
+{
+	u32 db_idx = be32_to_cpu(rx->q_resources->db_index);
+
+	iowrite32be(rx->desc.fill_cnt, &priv->db_bar2[db_idx]);
+}
+
+static enum pkt_hash_types gve_rss_type(__be16 pkt_flags)
+{
+	if (likely(pkt_flags & (GVE_RXF_TCP | GVE_RXF_UDP)))
+		return PKT_HASH_TYPE_L4;
+	if (pkt_flags & (GVE_RXF_IPV4 | GVE_RXF_IPV6))
+		return PKT_HASH_TYPE_L3;
+	return PKT_HASH_TYPE_L2;
+}
+
+static struct sk_buff *gve_rx_copy(struct net_device *dev,
+				   struct napi_struct *napi,
+				   struct gve_rx_slot_page_info *page_info,
+				   u16 len)
+{
+	struct sk_buff *skb = napi_alloc_skb(napi, len);
+	void *va = page_info->page_address + GVE_RX_PAD +
+		   page_info->page_offset;
+
+	if (unlikely(!skb))
+		return NULL;
+
+	__skb_put(skb, len);
+
+	skb_copy_to_linear_data(skb, va, len);
+
+	skb->protocol = eth_type_trans(skb, dev);
+	return skb;
+}
+
+static struct sk_buff *gve_rx_add_frags(struct net_device *dev,
+					struct napi_struct *napi,
+					struct gve_rx_slot_page_info *page_info,
+					u16 len)
+{
+	struct sk_buff *skb = napi_get_frags(napi);
+
+	if (unlikely(!skb))
+		return NULL;
+
+	skb_add_rx_frag(skb, 0, page_info->page,
+			page_info->page_offset +
+			GVE_RX_PAD, len, PAGE_SIZE / 2);
+
+	return skb;
+}
+
+static void gve_rx_flip_buff(struct gve_rx_slot_page_info *page_info,
+			     struct gve_rx_data_slot *data_ring)
+{
+	u64 addr = be64_to_cpu(data_ring->qpl_offset);
+
+	page_info->page_offset ^= PAGE_SIZE / 2;
+	addr ^= PAGE_SIZE / 2;
+	data_ring->qpl_offset = cpu_to_be64(addr);
+}
+
+static bool gve_rx(struct gve_rx_ring *rx, struct gve_rx_desc *rx_desc,
+		   netdev_features_t feat)
+{
+	struct gve_rx_slot_page_info *page_info;
+	struct gve_priv *priv = rx->gve;
+	struct napi_struct *napi = &priv->ntfy_blocks[rx->ntfy_id].napi;
+	struct net_device *dev = priv->dev;
+	struct sk_buff *skb;
+	int pagecount;
+	u16 len;
+	u32 idx;
+
+	/* drop this packet */
+	if (unlikely(rx_desc->flags_seq & GVE_RXF_ERR))
+		return true;
+
+	len = be16_to_cpu(rx_desc->len) - GVE_RX_PAD;
+	idx = rx->data.cnt & rx->data.mask;
+	page_info = &rx->data.page_info[idx];
+
+	/* gvnic can only receive into registered segments. If the buffer
+	 * can't be recycled, our only choice is to copy the data out of
+	 * it so that we can return it to the device.
+	 */
+
+	if (PAGE_SIZE == 4096) {
+		if (len <= priv->rx_copybreak) {
+			/* Just copy small packets */
+			skb = gve_rx_copy(dev, napi, page_info, len);
+			goto have_skb;
+		}
+		if (unlikely(!gve_can_recycle_pages(dev))) {
+			skb = gve_rx_copy(dev, napi, page_info, len);
+			goto have_skb;
+		}
+		pagecount = page_count(page_info->page);
+		if (pagecount == 1) {
+			/* No part of this page is used by any SKBs; we attach
+			 * the page fragment to a new SKB and pass it up the
+			 * stack.
+			 */
+			skb = gve_rx_add_frags(dev, napi, page_info, len);
+			if (!skb)
+				return true;
+			/* Make sure the kernel stack can't release the page */
+			get_page(page_info->page);
+			/* "flip" to other packet buffer on this page */
+			gve_rx_flip_buff(page_info, &rx->data.data_ring[idx]);
+		} else if (pagecount >= 2) {
+			/* We have previously passed the other half of this
+			 * page up the stack, but it has not yet been freed.
+			 */
+			skb = gve_rx_copy(dev, napi, page_info, len);
+		} else {
+			WARN(pagecount < 1, "Pagecount should never be < 1");
+			return false;
+		}
+	} else {
+		skb = gve_rx_copy(dev, napi, page_info, len);
+	}
+
+have_skb:
+	/* We didn't manage to allocate an skb but we haven't had any
+	 * reset worthy failures.
+	 */
+	if (!skb)
+		return true;
+
+	rx->data.cnt++;
+
+	if (likely(feat & NETIF_F_RXCSUM)) {
+		/* NIC passes up the partial sum */
+		if (rx_desc->csum)
+			skb->ip_summed = CHECKSUM_COMPLETE;
+		else
+			skb->ip_summed = CHECKSUM_NONE;
+		skb->csum = csum_unfold(rx_desc->csum);
+	}
+
+	/* parse flags & pass relevant info up */
+	if (likely(feat & NETIF_F_RXHASH) &&
+	    gve_needs_rss(rx_desc->flags_seq))
+		skb_set_hash(skb, be32_to_cpu(rx_desc->rss_hash),
+			     gve_rss_type(rx_desc->flags_seq));
+
+	if (skb_is_nonlinear(skb))
+		napi_gro_frags(napi);
+	else
+		napi_gro_receive(napi, skb);
+	return true;
+}
+
+static bool gve_rx_work_pending(struct gve_rx_ring *rx)
+{
+	struct gve_rx_desc *desc;
+	__be16 flags_seq;
+	u32 next_idx;
+
+	next_idx = rx->desc.cnt & rx->desc.mask;
+	desc = rx->desc.desc_ring + next_idx;
+
+	flags_seq = desc->flags_seq;
+	/* Make sure we have synchronized the seq no with the device */
+	smp_rmb();
+
+	return (GVE_SEQNO(flags_seq) == rx->desc.seqno);
+}
+
+bool gve_clean_rx_done(struct gve_rx_ring *rx, int budget,
+		       netdev_features_t feat)
+{
+	struct gve_priv *priv = rx->gve;
+	struct gve_rx_desc *desc;
+	u32 cnt = rx->desc.cnt;
+	u32 idx = cnt & rx->desc.mask;
+	u32 work_done = 0;
+	u64 bytes = 0;
+
+	desc = rx->desc.desc_ring + idx;
+	while ((GVE_SEQNO(desc->flags_seq) == rx->desc.seqno) &&
+	       work_done < budget) {
+		netif_info(priv, rx_status, priv->dev,
+			   "[%d] idx=%d desc=%p desc->flags_seq=0x%x\n",
+			   rx->q_num, idx, desc, desc->flags_seq);
+		netif_info(priv, rx_status, priv->dev,
+			   "[%d] seqno=%d rx->desc.seqno=%d\n",
+			   rx->q_num, GVE_SEQNO(desc->flags_seq),
+			   rx->desc.seqno);
+		bytes += be16_to_cpu(desc->len) - GVE_RX_PAD;
+		if (!gve_rx(rx, desc, feat))
+			gve_schedule_reset(priv);
+		cnt++;
+		idx = cnt & rx->desc.mask;
+		desc = rx->desc.desc_ring + idx;
+		rx->desc.seqno = gve_next_seqno(rx->desc.seqno);
+		work_done++;
+	}
+
+	if (!work_done)
+		return false;
+
+	u64_stats_update_begin(&rx->statss);
+	rx->rpackets += work_done;
+	rx->rbytes += bytes;
+	u64_stats_update_end(&rx->statss);
+	rx->desc.cnt = cnt;
+	rx->desc.fill_cnt += work_done;
+
+	/* restock desc ring slots */
+	dma_wmb();	/* Ensure descs are visible before ringing doorbell */
+	gve_rx_write_doorbell(priv, rx);
+	return gve_rx_work_pending(rx);
+}
+
+bool gve_rx_poll(struct gve_notify_block *block, int budget)
+{
+	struct gve_rx_ring *rx = block->rx;
+	netdev_features_t feat;
+	bool repoll = false;
+
+	feat = block->napi.dev->features;
+
+	/* If budget is 0, do all the work */
+	if (budget == 0)
+		budget = INT_MAX;
+
+	if (budget > 0)
+		repoll |= gve_clean_rx_done(rx, budget, feat);
+	else
+		repoll |= gve_rx_work_pending(rx);
+	return repoll;
+}