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[2620:137:e000::1:20]) by mx.google.com with ESMTP id g4-20020aa7c584000000b0045bd677b3d5si2014188edq.342.2022.11.11.07.00.23; Fri, 11 Nov 2022 07:01:23 -0800 (PST) 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; 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=fail (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=huawei.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234679AbiKKOzR (ORCPT + 99 others); Fri, 11 Nov 2022 09:55:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58096 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234610AbiKKOzO (ORCPT ); Fri, 11 Nov 2022 09:55:14 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 04377DEB6 for ; Fri, 11 Nov 2022 06:55:13 -0800 (PST) Received: from kwepemi100025.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4N81vf1g5LzmVpN; Fri, 11 Nov 2022 22:54:54 +0800 (CST) Received: from DESKTOP-27KDQMV.china.huawei.com (10.174.148.223) by kwepemi100025.china.huawei.com (7.221.188.158) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 11 Nov 2022 22:55:09 +0800 From: "Longpeng(Mike)" To: , , , CC: , , , , , , Longpeng Subject: [PATCH] vp_vdpa: harden the logic of set status Date: Fri, 11 Nov 2022 22:55:05 +0800 Message-ID: <20221111145505.1232-1-longpeng2@huawei.com> X-Mailer: git-send-email 2.25.0.windows.1 MIME-Version: 1.0 X-Originating-IP: [10.174.148.223] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemi100025.china.huawei.com (7.221.188.158) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS 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?1749212341001391471?= X-GMAIL-MSGID: =?utf-8?q?1749212341001391471?= From: Longpeng 1. We should not set status to 0 when invoking vp_vdpa_set_status(). 2. The driver MUST wait for a read of device_status to return 0 before reinitializing the device. Signed-off-by: Longpeng --- drivers/vdpa/virtio_pci/vp_vdpa.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c index d448db0c4de3..d35fac5cde11 100644 --- a/drivers/vdpa/virtio_pci/vp_vdpa.c +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c @@ -212,8 +212,12 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status) { struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa); struct virtio_pci_modern_device *mdev = vp_vdpa_to_mdev(vp_vdpa); - u8 s = vp_vdpa_get_status(vdpa); + u8 s; + + /* We should never be setting status to 0. */ + BUG_ON(status == 0); + s = vp_vdpa_get_status(vdpa); if (status & VIRTIO_CONFIG_S_DRIVER_OK && !(s & VIRTIO_CONFIG_S_DRIVER_OK)) { vp_vdpa_request_irq(vp_vdpa); @@ -229,6 +233,11 @@ static int vp_vdpa_reset(struct vdpa_device *vdpa) u8 s = vp_vdpa_get_status(vdpa); vp_modern_set_status(mdev, 0); + /* After writing 0 to device_status, the driver MUST wait for a read of + * device_status to return 0 before reinitializing the device. + */ + while (vp_modern_get_status(mdev)) + msleep(1); if (s & VIRTIO_CONFIG_S_DRIVER_OK) vp_vdpa_free_irq(vp_vdpa);