From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC387C433DB for ; Mon, 28 Dec 2020 14:22:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C18E022B2C for ; Mon, 28 Dec 2020 14:22:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2502695AbgL1OWg (ORCPT ); Mon, 28 Dec 2020 09:22:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:58200 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2502668AbgL1OWb (ORCPT ); Mon, 28 Dec 2020 09:22:31 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6E0B322B2C; Mon, 28 Dec 2020 14:21:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609165310; bh=+b53wZI83On3aGmgbPMhWqXugTD39OtO0fF5cNEUbHU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vc7epCMYW0uUesdzsujixAw6sw6lDYCD+5n1EMywV8H88hG5ZSYBnxOPKvqieuApb w+aV1tsyYAt16jkai7peinrvrap8EXmtOLuku1ms8XiymXLIUMyclNbVOBSWuAPfCN kTpR+txqMroIGcHDwG9/nfrwBxDJIQTIB4veeX5w= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eli Cohen , "Michael S. Tsirkin" , Sasha Levin Subject: [PATCH 5.10 488/717] vdpa/mlx5: Use write memory barrier after updating CQ index Date: Mon, 28 Dec 2020 13:48:06 +0100 Message-Id: <20201228125044.344626701@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228125020.963311703@linuxfoundation.org> References: <20201228125020.963311703@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eli Cohen [ Upstream commit 83ef73b27eb2363f44faf9c3ee28a3fe752cfd15 ] Make sure to put dma write memory barrier after updating CQ consumer index so the hardware knows that there are available CQE slots in the queue. Failure to do this can cause the update of the RX doorbell record to get updated before the CQ consumer index resulting in CQ overrun. Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices") Signed-off-by: Eli Cohen Link: https://lore.kernel.org/r/20201209140004.15892-1-elic@nvidia.com Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin --- drivers/vdpa/mlx5/net/mlx5_vnet.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c index 1fa6fcac82992..81b932f72e103 100644 --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c @@ -464,6 +464,11 @@ static int mlx5_vdpa_poll_one(struct mlx5_vdpa_cq *vcq) static void mlx5_vdpa_handle_completions(struct mlx5_vdpa_virtqueue *mvq, int num) { mlx5_cq_set_ci(&mvq->cq.mcq); + + /* make sure CQ cosumer update is visible to the hardware before updating + * RX doorbell record. + */ + dma_wmb(); rx_post(&mvq->vqqp, num); if (mvq->event_cb.callback) mvq->event_cb.callback(mvq->event_cb.private); -- 2.27.0