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Subject[PATCH RFC 37/39] xen-netback: xen_shim_domain() support
Date

GNTTABOP_map_grant_ref treats host_address as an OUT parameter for
xen_shim_domain(). After doing gnttab_map_refs, we check each map op
struct and replace the page passed with the page returned by the
hypercall.

Note that mmap_pages is just a placeholder when netback runs in
xen_shim_domain() mode.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
drivers/net/xen-netback/netback.c | 25 +++++++++++++++++++++----
1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 80aae3a32c2a..a5dd6de6d3e6 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -324,6 +324,9 @@ struct xenvif_tx_cb {

#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)

+/* Selects host map only if on native Xen */
+#define GNTTAB_host_map (xen_shim_domain() ? 0 : GNTMAP_host_map)
+
static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
u16 pending_idx,
struct xen_netif_tx_request *txp,
@@ -332,9 +335,12 @@ static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
{
queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
- GNTMAP_host_map | GNTMAP_readonly,
+ GNTTAB_host_map | GNTMAP_readonly,
txp->gref, queue->vif->domid);

+ if (xen_shim_domain())
+ mop->host_addr = 0;
+
memcpy(&queue->pending_tx_info[pending_idx].req, txp,
sizeof(*txp));
queue->pending_tx_info[pending_idx].extra_count = extra_count;
@@ -405,6 +411,12 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *que
return gop;
}

+static inline void xenvif_grant_replace_page(struct xenvif_queue *queue,
+ u16 pending_idx, u32 mapping_idx)
+{
+ queue->mmap_pages[pending_idx] = queue->pages_to_map[mapping_idx];
+}
+
static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
u16 pending_idx,
grant_handle_t handle)
@@ -481,6 +493,10 @@ static int xenvif_tx_check_gop(struct xenvif_queue *queue,
xenvif_grant_handle_set(queue,
pending_idx,
gop_map->handle);
+
+ if (!err && xen_shim_domain())
+ xenvif_grant_replace_page(queue, pending_idx,
+ gop_map - queue->tx_map_ops);
/* Had a previous error? Invalidate this fragment. */
if (unlikely(err)) {
xenvif_idx_unmap(queue, pending_idx);
@@ -1268,7 +1284,7 @@ static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
queue->mmap_pages[pending_idx];
gnttab_set_unmap_op(gop,
idx_to_kaddr(queue, pending_idx),
- GNTMAP_host_map,
+ GNTTAB_host_map,
queue->grant_tx_handle[pending_idx]);
xenvif_grant_handle_reset(queue, pending_idx);
++gop;
@@ -1394,7 +1410,7 @@ void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)

gnttab_set_unmap_op(&tx_unmap_op,
idx_to_kaddr(queue, pending_idx),
- GNTMAP_host_map,
+ GNTTAB_host_map,
queue->grant_tx_handle[pending_idx]);
xenvif_grant_handle_reset(queue, pending_idx);

@@ -1622,7 +1638,7 @@ static int __init netback_init(void)
{
int rc = 0;

- if (!xen_domain())
+ if (!xen_domain() && !xen_shim_domain_get())
return -ENODEV;

/* Allow as many queues as there are CPUs but max. 8 if user has not
@@ -1663,6 +1679,7 @@ static void __exit netback_fini(void)
debugfs_remove_recursive(xen_netback_dbg_root);
#endif /* CONFIG_DEBUG_FS */
xenvif_xenbus_fini();
+ xen_shim_domain_put();
}
module_exit(netback_fini);

--
2.11.0
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