From 42557dab78edc8235aba5b441f2eb35f725a0ede Mon Sep 17 00:00:00 2001
From: Lijun Pan <ljp@linux.ibm.com>
Date: Fri, 12 Feb 2021 20:48:40 -0600
Subject: [PATCH] ibmvnic: add memory barrier to protect long term buffer
References: bsc#1184114 ltc#192237 bsc#1182485 ltc#191591
Patch-mainline: v5.12-rc1
Git-commit: 42557dab78edc8235aba5b441f2eb35f725a0ede
dma_rmb() barrier is added to load the long term buffer before copying
it to socket buffer; and dma_wmb() barrier is added to update the
long term buffer before it being accessed by VIOS (virtual i/o server).
Fixes: 032c5e82847a ("Driver for IBM System i/p VNIC protocol")
Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
Acked-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
drivers/net/ethernet/ibm/ibmvnic.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 621be6d2da97..f6402a20ba32 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1700,6 +1700,9 @@ static netdev_tx_t ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
skb_copy_from_linear_data(skb, dst, skb->len);
}
+ /* post changes to long_term_buff *dst before VIOS accessing it */
+ dma_wmb();
+
tx_pool->consumer_index =
(tx_pool->consumer_index + 1) % tx_pool->num_buffers;
@@ -2539,6 +2542,8 @@ static int ibmvnic_poll(struct napi_struct *napi, int budget)
offset = be16_to_cpu(next->rx_comp.off_frame_data);
flags = next->rx_comp.flags;
skb = rx_buff->skb;
+ /* load long_term_buff before copying to skb */
+ dma_rmb();
skb_copy_to_linear_data(skb, rx_buff->data + offset,
length);
--
2.26.2