From nobody Mon Apr 13 11:42:14 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67502C433FE for ; Fri, 11 Nov 2022 14:55:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234688AbiKKOzU (ORCPT ); Fri, 11 Nov 2022 09:55:20 -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 Content-Transfer-Encoding: quoted-printable 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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 *vdp= a, u8 status) { struct vp_vdpa *vp_vdpa =3D vdpa_to_vp(vdpa); struct virtio_pci_modern_device *mdev =3D vp_vdpa_to_mdev(vp_vdpa); - u8 s =3D vp_vdpa_get_status(vdpa); + u8 s; + + /* We should never be setting status to 0. */ + BUG_ON(status =3D=3D 0); =20 + s =3D 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 =3D vp_vdpa_get_status(vdpa); =20 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); =20 if (s & VIRTIO_CONFIG_S_DRIVER_OK) vp_vdpa_free_irq(vp_vdpa); --=20 2.23.0