net/xen-netback: Make it running on 64KB page granularity
The PV network protocol is using 4KB page granularity. The goal of this
patch is to allow a Linux using 64KB page granularity working as a
network backend on a non-modified Xen.
It's only necessary to adapt the ring size and break skb data in small
chunk of 4KB. The rest of the code is relying on the grant table code.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index c4e6c02..e481f37 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -152,9 +152,9 @@
static int xenvif_rx_ring_slots_needed(struct xenvif *vif)
{
if (vif->gso_mask)
- return DIV_ROUND_UP(vif->dev->gso_max_size, PAGE_SIZE) + 1;
+ return DIV_ROUND_UP(vif->dev->gso_max_size, XEN_PAGE_SIZE) + 1;
else
- return DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE);
+ return DIV_ROUND_UP(vif->dev->mtu, XEN_PAGE_SIZE);
}
static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
@@ -274,6 +274,80 @@
return meta;
}
+struct gop_frag_copy {
+ struct xenvif_queue *queue;
+ struct netrx_pending_operations *npo;
+ struct xenvif_rx_meta *meta;
+ int head;
+ int gso_type;
+
+ struct page *page;
+};
+
+static void xenvif_setup_copy_gop(unsigned long gfn,
+ unsigned int offset,
+ unsigned int *len,
+ struct gop_frag_copy *info)
+{
+ struct gnttab_copy *copy_gop;
+ struct xen_page_foreign *foreign;
+ /* Convenient aliases */
+ struct xenvif_queue *queue = info->queue;
+ struct netrx_pending_operations *npo = info->npo;
+ struct page *page = info->page;
+
+ BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
+
+ if (npo->copy_off == MAX_BUFFER_OFFSET)
+ info->meta = get_next_rx_buffer(queue, npo);
+
+ if (npo->copy_off + *len > MAX_BUFFER_OFFSET)
+ *len = MAX_BUFFER_OFFSET - npo->copy_off;
+
+ copy_gop = npo->copy + npo->copy_prod++;
+ copy_gop->flags = GNTCOPY_dest_gref;
+ copy_gop->len = *len;
+
+ foreign = xen_page_foreign(page);
+ if (foreign) {
+ copy_gop->source.domid = foreign->domid;
+ copy_gop->source.u.ref = foreign->gref;
+ copy_gop->flags |= GNTCOPY_source_gref;
+ } else {
+ copy_gop->source.domid = DOMID_SELF;
+ copy_gop->source.u.gmfn = gfn;
+ }
+ copy_gop->source.offset = offset;
+
+ copy_gop->dest.domid = queue->vif->domid;
+ copy_gop->dest.offset = npo->copy_off;
+ copy_gop->dest.u.ref = npo->copy_gref;
+
+ npo->copy_off += *len;
+ info->meta->size += *len;
+
+ /* Leave a gap for the GSO descriptor. */
+ if (info->head && ((1 << info->gso_type) & queue->vif->gso_mask))
+ queue->rx.req_cons++;
+
+ info->head = 0; /* There must be something in this buffer now */
+}
+
+static void xenvif_gop_frag_copy_grant(unsigned long gfn,
+ unsigned offset,
+ unsigned int len,
+ void *data)
+{
+ unsigned int bytes;
+
+ while (len) {
+ bytes = len;
+ xenvif_setup_copy_gop(gfn, offset, &bytes, data);
+ offset += bytes;
+ len -= bytes;
+ }
+}
+
/*
* Set up the grant operations for this fragment. If it's a flipping
* interface, we also set up the unmap request from here.
@@ -283,83 +357,52 @@
struct page *page, unsigned long size,
unsigned long offset, int *head)
{
- struct gnttab_copy *copy_gop;
- struct xenvif_rx_meta *meta;
+ struct gop_frag_copy info = {
+ .queue = queue,
+ .npo = npo,
+ .head = *head,
+ .gso_type = XEN_NETIF_GSO_TYPE_NONE,
+ };
unsigned long bytes;
- int gso_type = XEN_NETIF_GSO_TYPE_NONE;
if (skb_is_gso(skb)) {
if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
- gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
+ info.gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
- gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
+ info.gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
}
/* Data must not cross a page boundary. */
BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
- meta = npo->meta + npo->meta_prod - 1;
+ info.meta = npo->meta + npo->meta_prod - 1;
/* Skip unused frames from start of page */
page += offset >> PAGE_SHIFT;
offset &= ~PAGE_MASK;
while (size > 0) {
- struct xen_page_foreign *foreign;
-
BUG_ON(offset >= PAGE_SIZE);
- BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
-
- if (npo->copy_off == MAX_BUFFER_OFFSET)
- meta = get_next_rx_buffer(queue, npo);
bytes = PAGE_SIZE - offset;
if (bytes > size)
bytes = size;
- if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
- bytes = MAX_BUFFER_OFFSET - npo->copy_off;
-
- copy_gop = npo->copy + npo->copy_prod++;
- copy_gop->flags = GNTCOPY_dest_gref;
- copy_gop->len = bytes;
-
- foreign = xen_page_foreign(page);
- if (foreign) {
- copy_gop->source.domid = foreign->domid;
- copy_gop->source.u.ref = foreign->gref;
- copy_gop->flags |= GNTCOPY_source_gref;
- } else {
- copy_gop->source.domid = DOMID_SELF;
- copy_gop->source.u.gmfn =
- virt_to_gfn(page_address(page));
- }
- copy_gop->source.offset = offset;
-
- copy_gop->dest.domid = queue->vif->domid;
- copy_gop->dest.offset = npo->copy_off;
- copy_gop->dest.u.ref = npo->copy_gref;
-
- npo->copy_off += bytes;
- meta->size += bytes;
-
- offset += bytes;
+ info.page = page;
+ gnttab_foreach_grant_in_range(page, offset, bytes,
+ xenvif_gop_frag_copy_grant,
+ &info);
size -= bytes;
+ offset = 0;
- /* Next frame */
- if (offset == PAGE_SIZE && size) {
+ /* Next page */
+ if (size) {
BUG_ON(!PageCompound(page));
page++;
- offset = 0;
}
-
- /* Leave a gap for the GSO descriptor. */
- if (*head && ((1 << gso_type) & queue->vif->gso_mask))
- queue->rx.req_cons++;
-
- *head = 0; /* There must be something in this buffer now. */
-
}
+
+ *head = info.head;
}
/*
@@ -758,7 +801,7 @@
first->size -= txp->size;
slots++;
- if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
+ if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
txp->offset, txp->size);
xenvif_fatal_tx_err(queue->vif);
@@ -1339,11 +1382,11 @@
}
/* No crossing a page as the payload mustn't fragment. */
- if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
+ if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
netdev_err(queue->vif->dev,
"txreq.offset: %u, size: %u, end: %lu\n",
txreq.offset, txreq.size,
- (unsigned long)(txreq.offset&~PAGE_MASK) + txreq.size);
+ (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size);
xenvif_fatal_tx_err(queue->vif);
break;
}
@@ -1409,7 +1452,7 @@
virt_to_gfn(skb->data);
queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
queue->tx_copy_ops[*copy_ops].dest.offset =
- offset_in_page(skb->data);
+ offset_in_page(skb->data) & ~XEN_PAGE_MASK;
queue->tx_copy_ops[*copy_ops].len = data_len;
queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
@@ -1894,7 +1937,7 @@
goto err;
txs = (struct xen_netif_tx_sring *)addr;
- BACK_RING_INIT(&queue->tx, txs, PAGE_SIZE);
+ BACK_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
&rx_ring_ref, 1, &addr);
@@ -1902,7 +1945,7 @@
goto err;
rxs = (struct xen_netif_rx_sring *)addr;
- BACK_RING_INIT(&queue->rx, rxs, PAGE_SIZE);
+ BACK_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
return 0;