From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:32776 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967147AbeEXJr6 (ORCPT ); Thu, 24 May 2018 05:47:58 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Regis Duchesne , Ronak Doshi , "David S. Miller" Subject: [PATCH 4.9 07/96] vmxnet3: use DMA memory barriers where required Date: Thu, 24 May 2018 11:37:50 +0200 Message-Id: <20180524093606.038682285@linuxfoundation.org> In-Reply-To: <20180524093605.602125311@linuxfoundation.org> References: <20180524093605.602125311@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: "hpreg@vmware.com" [ Upstream commit f3002c1374fb2367c9d8dbb28852791ef90d2bac ] The gen bits must be read first from (resp. written last to) DMA memory. The proper way to enforce this on Linux is to call dma_rmb() (resp. dma_wmb()). Signed-off-by: Regis Duchesne Acked-by: Ronak Doshi Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/vmxnet3/vmxnet3_drv.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) --- a/drivers/net/vmxnet3/vmxnet3_drv.c +++ b/drivers/net/vmxnet3/vmxnet3_drv.c @@ -369,6 +369,11 @@ vmxnet3_tq_tx_complete(struct vmxnet3_tx gdesc = tq->comp_ring.base + tq->comp_ring.next2proc; while (VMXNET3_TCD_GET_GEN(&gdesc->tcd) == tq->comp_ring.gen) { + /* Prevent any &gdesc->tcd field from being (speculatively) + * read before (&gdesc->tcd)->gen is read. + */ + dma_rmb(); + completed += vmxnet3_unmap_pkt(VMXNET3_TCD_GET_TXIDX( &gdesc->tcd), tq, adapter->pdev, adapter); @@ -1099,6 +1104,11 @@ vmxnet3_tq_xmit(struct sk_buff *skb, str gdesc->txd.tci = skb_vlan_tag_get(skb); } + /* Ensure that the write to (&gdesc->txd)->gen will be observed after + * all other writes to &gdesc->txd. + */ + dma_wmb(); + /* finally flips the GEN bit of the SOP desc. */ gdesc->dword[2] = cpu_to_le32(le32_to_cpu(gdesc->dword[2]) ^ VMXNET3_TXD_GEN); @@ -1286,6 +1296,12 @@ vmxnet3_rq_rx_complete(struct vmxnet3_rx */ break; } + + /* Prevent any rcd field from being (speculatively) read before + * rcd->gen is read. + */ + dma_rmb(); + BUG_ON(rcd->rqID != rq->qid && rcd->rqID != rq->qid2 && rcd->rqID != rq->dataRingQid); idx = rcd->rxdIdx; @@ -1515,6 +1531,12 @@ rcd_done: ring->next2comp = idx; num_to_alloc = vmxnet3_cmd_ring_desc_avail(ring); ring = rq->rx_ring + ring_idx; + + /* Ensure that the writes to rxd->gen bits will be observed + * after all other writes to rxd objects. + */ + dma_wmb(); + while (num_to_alloc) { vmxnet3_getRxDesc(rxd, &ring->base[ring->next2fill].rxd, &rxCmdDesc);