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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 61521C433FF for ; Fri, 2 Aug 2019 09:48:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 381272087E for ; Fri, 2 Aug 2019 09:48:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564739339; bh=xCUjBjZVjtJ9PULEzRtNCnrVM5LuoqkL8P4zCUhfJRo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=om15VFNcy06YPjQrAlok4MyMFJXpLweJqzXjxo4+ISEsYKPYqmBn/7v4gaNEskkR3 B67fXWAubVKMqL5thMha3PdxhoK4qWelGTlvr9QPLC9Syp4jMfYeF/rODHqbKb0LE0 +z4g5EKcPH1g6Dpc8MptyUEdgQTqOHqRbtCwKb18= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405262AbfHBJs6 (ORCPT ); Fri, 2 Aug 2019 05:48:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:54424 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405929AbfHBJsv (ORCPT ); Fri, 2 Aug 2019 05:48:51 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2CA002087E; Fri, 2 Aug 2019 09:48:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564739330; bh=xCUjBjZVjtJ9PULEzRtNCnrVM5LuoqkL8P4zCUhfJRo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f5HCjPeveLXn/Etih1smhIEStjRwXPsBwZQqA/5nSyKRCb6jNOGFqlZsIff8VWnoJ Izzf8QFrMpcftB340KlRN9kuzcE4YpkqIYnVxUF0/vywu7LodJr8Pz5T/+BotM1l+/ bdaFvHhS3+tPihATl9GJF1WsSbltl1oYelkPSTu8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Riley , Gerd Hoffmann , Sasha Levin Subject: [PATCH 4.9 170/223] drm/virtio: Add memory barriers for capset cache. Date: Fri, 2 Aug 2019 11:36:35 +0200 Message-Id: <20190802092248.966552546@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190802092238.692035242@linuxfoundation.org> References: <20190802092238.692035242@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 9ff3a5c88e1f1ab17a31402b96d45abe14aab9d7 ] After data is copied to the cache entry, atomic_set is used indicate that the data is the entry is valid without appropriate memory barriers. Similarly the read side was missing the corresponding memory barriers. Signed-off-by: David Riley Link: http://patchwork.freedesktop.org/patch/msgid/20190610211810.253227-5-davidriley@chromium.org Signed-off-by: Gerd Hoffmann Signed-off-by: Sasha Levin --- drivers/gpu/drm/virtio/virtgpu_ioctl.c | 3 +++ drivers/gpu/drm/virtio/virtgpu_vq.c | 2 ++ 2 files changed, 5 insertions(+) diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c index 54639395aba0..a3559b1a3a0f 100644 --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c @@ -521,6 +521,9 @@ static int virtio_gpu_get_caps_ioctl(struct drm_device *dev, ret = wait_event_timeout(vgdev->resp_wq, atomic_read(&cache_ent->is_valid), 5 * HZ); + /* is_valid check must proceed before copy of the cache entry. */ + smp_rmb(); + ptr = cache_ent->caps_cache; copy_exit: diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c index 52436b3c01bb..a1b3ea1ccb65 100644 --- a/drivers/gpu/drm/virtio/virtgpu_vq.c +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c @@ -618,6 +618,8 @@ static void virtio_gpu_cmd_capset_cb(struct virtio_gpu_device *vgdev, cache_ent->id == le32_to_cpu(cmd->capset_id)) { memcpy(cache_ent->caps_cache, resp->capset_data, cache_ent->size); + /* Copy must occur before is_valid is signalled. */ + smp_wmb(); atomic_set(&cache_ent->is_valid, 1); break; } -- 2.20.1