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[2620:137:e000::1:20]) by mx.google.com with ESMTP id i30-20020a63585e000000b0052856cec94asi3004308pgm.884.2023.05.09.20.20.54; Tue, 09 May 2023 20:21:10 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@bytedance.com header.s=google header.b=AJvosUCn; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=bytedance.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235177AbjEJC5J (ORCPT + 99 others); Tue, 9 May 2023 22:57:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229536AbjEJC5I (ORCPT ); Tue, 9 May 2023 22:57:08 -0400 Received: from mail-pf1-x432.google.com (mail-pf1-x432.google.com [IPv6:2607:f8b0:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2533030FF for ; Tue, 9 May 2023 19:56:42 -0700 (PDT) Received: by mail-pf1-x432.google.com with SMTP id d2e1a72fcca58-643b7b8f8ceso3042328b3a.1 for ; Tue, 09 May 2023 19:56:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1683687401; x=1686279401; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=hTSesuixdo5vZ8I9+v28R7iSHBf2PWhulvCTlSJ6srA=; b=AJvosUCnaL7DVrTLt0wEHVdYm9nezT1Xn8WsRYZ5yIuyP3499YqOnLadpQLSAn9yt2 05U+onyUhUO0mNusq+LU34DX+jo3WaPD3xduRVgLNMAF77mNjHIkNOYFHbwMi2ZH2trk WPZ9SWFvn+9Oms0zV++Xge+Rah4vggZDy/1Uo3NnXa+zOnJLgi0MH0+/ob20TT8QWfu1 +J9vUcfhAUXHBr43YbyXF3BjQRTXP98x9z9WWJpyRvW/zsSk21J5ZhzoJQPAtU2vN7IN xvHx8OiV3wiV9PenK6h+w2quENNK8h/hjJOEtp1BW6HfgIuiAPKYOvDkMTW2ow/8lFG0 T2vQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683687401; x=1686279401; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=hTSesuixdo5vZ8I9+v28R7iSHBf2PWhulvCTlSJ6srA=; b=j4NY28Z1HqdLcqcacwLzargonPtf9TE/AHTbEwNWSJyEqJa5a8I501bojnrmYxiiLb ajkn7UQA+Mx1HGcztfcoJa3YZS1fNMRrxDJudStERpZHTYWJsGJBtx9Ioossp65X0/dm aGxisfeSGCwEJEZjrZeFwEsCVmH+ehUVBLOovetEIXvypyB7bz0BzsdFhqVR/QvqoXR5 MkhdM/xp3vSKy7Zn6s5ZfBfbhP0zmj9Xj/HhDiW4nIWkME6Jmj6eWMWgM1FTXP7KOteV t00bWpDNVSVloxS54eS72lXiuadH/eFyLXfkr/hG8Cy0pV83m4+Mk3JMZdZPtmqP6xNP DSnA== X-Gm-Message-State: AC+VfDxo9+Yql+hBblAXc9cxVn6M8XZQ41151RmpTVx/g4LIvi8tlkgt Akzhht9kEjv92CZffqnMr2K8Vw== X-Received: by 2002:a05:6a20:4421:b0:101:914e:da75 with SMTP id ce33-20020a056a20442100b00101914eda75mr3401063pzb.25.1683687401584; Tue, 09 May 2023 19:56:41 -0700 (PDT) Received: from always-x1.bytedance.net ([61.213.176.13]) by smtp.gmail.com with ESMTPSA id h13-20020a63e14d000000b00524cfd635cesm2083080pgk.69.2023.05.09.19.56.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 May 2023 19:56:41 -0700 (PDT) From: zhenwei pi To: mst@redhat.com, jasowang@redhat.com Cc: virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, xuanzhuo@linux.alibaba.com, zhenwei pi , Joerg Roedel Subject: [PATCH] virtio_ring: use u32 for virtio_max_dma_size Date: Wed, 10 May 2023 10:54:37 +0800 Message-Id: <20230510025437.377807-1-pizhenwei@bytedance.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1765475741418976836?= X-GMAIL-MSGID: =?utf-8?q?1765475741418976836?= Both split ring and packed ring use 32bits to describe the length of a descriptor: see struct vring_desc and struct vring_packed_desc. This means the max segment size supported by virtio is U32_MAX. An example of virtio_max_dma_size in virtio_blk.c: u32 v, max_size; max_size = virtio_max_dma_size(vdev); -> implicit convert err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX, struct virtio_blk_config, size_max, &v); max_size = min(max_size, v); There is a risk during implicit convert here, once virtio_max_dma_size returns 4G, max_size becomes 0. Fixes: e6d6dd6c875e ("virtio: Introduce virtio_max_dma_size()") Cc: Joerg Roedel Signed-off-by: zhenwei pi --- drivers/virtio/virtio_ring.c | 12 ++++++++---- include/linux/virtio.h | 2 +- 2 files changed, 9 insertions(+), 5 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index c5310eaf8b46..55cfecf030a1 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -289,12 +289,16 @@ static bool vring_use_dma_api(const struct virtio_device *vdev) return false; } -size_t virtio_max_dma_size(const struct virtio_device *vdev) +u32 virtio_max_dma_size(const struct virtio_device *vdev) { - size_t max_segment_size = SIZE_MAX; + u32 max_segment_size = U32_MAX; - if (vring_use_dma_api(vdev)) - max_segment_size = dma_max_mapping_size(vdev->dev.parent); + if (vring_use_dma_api(vdev)) { + size_t max_dma_size = dma_max_mapping_size(vdev->dev.parent); + + if (max_dma_size < max_segment_size) + max_segment_size = max_dma_size; + } return max_segment_size; } diff --git a/include/linux/virtio.h b/include/linux/virtio.h index b93238db94e3..1a605f408329 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -147,7 +147,7 @@ int virtio_device_restore(struct virtio_device *dev); #endif void virtio_reset_device(struct virtio_device *dev); -size_t virtio_max_dma_size(const struct virtio_device *vdev); +u32 virtio_max_dma_size(const struct virtio_device *vdev); #define virtio_device_for_each_vq(vdev, vq) \ list_for_each_entry(vq, &vdev->vqs, list)