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=-8.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,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 0DE26C4321A for ; Mon, 10 Jun 2019 21:18:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D858020859 for ; Mon, 10 Jun 2019 21:18:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="FCNlBwOe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390048AbfFJVSa (ORCPT ); Mon, 10 Jun 2019 17:18:30 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:38030 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390027AbfFJVS3 (ORCPT ); Mon, 10 Jun 2019 17:18:29 -0400 Received: by mail-pl1-f196.google.com with SMTP id f97so4139943plb.5 for ; Mon, 10 Jun 2019 14:18:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=8nq9Im362lbv4azULZvOC9Ag2G2ZekGR7CCYDprgGF8=; b=FCNlBwOefmxV9kPIPrpaBd9HyXv2yEenUtOaw++Q3b8DYUHSXihBeppW/SIaMfVj5X jP4AxfQTg5gmZCoy5a/s/T7DlqJANXVakIx9E4W7j2FILbiSvu0yUKGMDBpgoqSfIRkG 8f4i+L37sKl82vKcRN0id86xV7zHPQ7j7xd8s= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=8nq9Im362lbv4azULZvOC9Ag2G2ZekGR7CCYDprgGF8=; b=DZAfPr2SJGiUtwDfrHMAbJwnyt4TVHLkh0c0vQtWwWC0LNmndrml4r1mx+tvRsMxbZ uKTrg1CBD33PKDybVpMuBrfCNm7locdwpHjeG4a8RQIaAEnun+jwZuMb1KUQOcYGAABH iWWotPL8tGUjj/iQN/vRSzsQqQTGNbZseQ4ToF9J08tOXNWeqPmybF2C8IzrX4+Jxfdn zLJcAC2jHpnNP+6rVX4VnCK0xEC1m/j40tdr/sq/xejOusPxUlzb8XTkMKCfGD63RxKL VO1sHRU8gpnc4H9PdYrSHR/I7Y1XvA9iPmi9fZIDqVrktySLZb/74FE+9ymmLI1Za73G 03jQ== X-Gm-Message-State: APjAAAWazsJPoqzVkxCtBnSeqhah1y5M2POx26dtrDZMQJfUwV+s90/9 71CZvvyAeUM7i5NdPu6JA10NQQ== X-Google-Smtp-Source: APXvYqyMASM4YCvHQ5Ip2z9vUnGHsH6b1vlzz/iXUjTKHtkcitMyf7/FMV1pmortsoFPZ6YfD+n6Cw== X-Received: by 2002:a17:902:5c5:: with SMTP id f63mr72275000plf.176.1560201508490; Mon, 10 Jun 2019 14:18:28 -0700 (PDT) Received: from localhost ([2620:15c:202:1:e9ae:bd45:1bd9:e60d]) by smtp.gmail.com with ESMTPSA id q20sm16377982pgq.66.2019.06.10.14.18.27 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 10 Jun 2019 14:18:27 -0700 (PDT) From: davidriley@chromium.org To: Gerd Hoffmann , dri-devel@lists.freedesktop.org, virtualization@lists.linux-foundation.org Cc: David Airlie , Daniel Vetter , linux-kernel@vger.kernel.org, David Riley Subject: [PATCH v2 4/4] drm/virtio: Add memory barriers for capset cache. Date: Mon, 10 Jun 2019 14:18:10 -0700 Message-Id: <20190610211810.253227-5-davidriley@chromium.org> X-Mailer: git-send-email 2.22.0.rc2.383.gf4fbbf30c2-goog In-Reply-To: <20190605234423.11348-1-davidriley@chromium.org> References: <20190605234423.11348-1-davidriley@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Riley 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 --- 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 88c1ed57a3c5..a50495083d6f 100644 --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c @@ -542,6 +542,9 @@ static int virtio_gpu_get_caps_ioctl(struct drm_device *dev, if (!ret) return -EBUSY; + /* is_valid check must proceed before copy of the cache entry. */ + smp_rmb(); + ptr = cache_ent->caps_cache; if (copy_to_user((void __user *)(unsigned long)args->addr, ptr, size)) diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c index dd5ead2541c2..c7a5ca027245 100644 --- a/drivers/gpu/drm/virtio/virtgpu_vq.c +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c @@ -583,6 +583,8 @@ 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; } -- 2.22.0.rc2.383.gf4fbbf30c2-goog