From 05310f31ca74673a96567fb14637b7d5d6c82ea5 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 27 Mar 2023 10:36:45 +0200 Subject: xen/netback: don't do grant copy across page boundary Fix xenvif_get_requests() not to do grant copy operations across local page boundaries. This requires to double the maximum number of copy operations per queue, as each copy could now be split into 2. Make sure that struct xenvif_tx_cb doesn't grow too large. Cc: stable@vger.kernel.org Fixes: ad7f402ae4f4 ("xen/netback: Ensure protocol headers don't fall in the non-linear area") Signed-off-by: Juergen Gross Reviewed-by: Paul Durrant Signed-off-by: Paolo Abeni --- drivers/net/xen-netback/netback.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) (limited to 'drivers/net/xen-netback/netback.c') diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 1b42676ca1418..111c179f161b5 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -334,6 +334,7 @@ static int xenvif_count_requests(struct xenvif_queue *queue, struct xenvif_tx_cb { u16 copy_pending_idx[XEN_NETBK_LEGACY_SLOTS_MAX + 1]; u8 copy_count; + u32 split_mask; }; #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb) @@ -361,6 +362,8 @@ static inline struct sk_buff *xenvif_alloc_skb(unsigned int size) struct sk_buff *skb = alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN, GFP_ATOMIC | __GFP_NOWARN); + + BUILD_BUG_ON(sizeof(*XENVIF_TX_CB(skb)) > sizeof(skb->cb)); if (unlikely(skb == NULL)) return NULL; @@ -396,11 +399,13 @@ static void xenvif_get_requests(struct xenvif_queue *queue, nr_slots = shinfo->nr_frags + 1; copy_count(skb) = 0; + XENVIF_TX_CB(skb)->split_mask = 0; /* Create copy ops for exactly data_len bytes into the skb head. */ __skb_put(skb, data_len); while (data_len > 0) { int amount = data_len > txp->size ? txp->size : data_len; + bool split = false; cop->source.u.ref = txp->gref; cop->source.domid = queue->vif->domid; @@ -413,6 +418,13 @@ static void xenvif_get_requests(struct xenvif_queue *queue, cop->dest.u.gmfn = virt_to_gfn(skb->data + skb_headlen(skb) - data_len); + /* Don't cross local page boundary! */ + if (cop->dest.offset + amount > XEN_PAGE_SIZE) { + amount = XEN_PAGE_SIZE - cop->dest.offset; + XENVIF_TX_CB(skb)->split_mask |= 1U << copy_count(skb); + split = true; + } + cop->len = amount; cop->flags = GNTCOPY_source_gref; @@ -420,7 +432,8 @@ static void xenvif_get_requests(struct xenvif_queue *queue, pending_idx = queue->pending_ring[index]; callback_param(queue, pending_idx).ctx = NULL; copy_pending_idx(skb, copy_count(skb)) = pending_idx; - copy_count(skb)++; + if (!split) + copy_count(skb)++; cop++; data_len -= amount; @@ -441,7 +454,8 @@ static void xenvif_get_requests(struct xenvif_queue *queue, nr_slots--; } else { /* The copy op partially covered the tx_request. - * The remainder will be mapped. + * The remainder will be mapped or copied in the next + * iteration. */ txp->offset += amount; txp->size -= amount; @@ -539,6 +553,13 @@ static int xenvif_tx_check_gop(struct xenvif_queue *queue, pending_idx = copy_pending_idx(skb, i); newerr = (*gopp_copy)->status; + + /* Split copies need to be handled together. */ + if (XENVIF_TX_CB(skb)->split_mask & (1U << i)) { + (*gopp_copy)++; + if (!newerr) + newerr = (*gopp_copy)->status; + } if (likely(!newerr)) { /* The first frag might still have this slot mapped */ if (i < copy_count(skb) - 1 || !sharedslot) -- cgit v1.2.3 From 8fb8ebf9487785184846d04e915bfe327bf4ccd5 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 27 Mar 2023 10:36:46 +0200 Subject: xen/netback: remove not needed test in xenvif_tx_build_gops() The tests for the number of grant mapping or copy operations reaching the array size of the operations buffer at the end of the main loop in xenvif_tx_build_gops() isn't needed. The loop can handle at maximum MAX_PENDING_REQS transfer requests, as XEN_RING_NR_UNCONSUMED_REQUESTS() is taking unsent responses into consideration, too. Remove the tests. Suggested-by: Jan Beulich Signed-off-by: Juergen Gross Reviewed-by: Paul Durrant Signed-off-by: Paolo Abeni --- drivers/net/xen-netback/netback.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'drivers/net/xen-netback/netback.c') diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 111c179f161b5..4943be4fd99d8 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -1082,10 +1082,6 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue, __skb_queue_tail(&queue->tx_queue, skb); queue->tx.req_cons = idx; - - if ((*map_ops >= ARRAY_SIZE(queue->tx_map_ops)) || - (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops))) - break; } return; -- cgit v1.2.3 From 2eca98e5b24d01c02b46c67be05a5f98cc9789b1 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Wed, 29 Mar 2023 10:02:59 +0200 Subject: xen/netback: use same error messages for same errors Issue the same error message in case an illegal page boundary crossing has been detected in both cases where this is tested. Suggested-by: Jan Beulich Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Link: https://lore.kernel.org/r/20230329080259.14823-1-jgross@suse.com Signed-off-by: Paolo Abeni --- drivers/net/xen-netback/netback.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'drivers/net/xen-netback/netback.c') diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 4943be4fd99d8..c1501f41e2d82 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -994,10 +994,8 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue, /* No crossing a page as the payload mustn't fragment. */ 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&~XEN_PAGE_MASK) + txreq.size); + netdev_err(queue->vif->dev, "Cross page boundary, txreq.offset: %u, size: %u\n", + txreq.offset, txreq.size); xenvif_fatal_tx_err(queue->vif); break; } -- cgit v1.2.3