From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753723AbcDCM01 (ORCPT ); Sun, 3 Apr 2016 08:26:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59718 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751041AbcDCM0Z (ORCPT ); Sun, 3 Apr 2016 08:26:25 -0400 Date: Sun, 3 Apr 2016 15:26:22 +0300 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org, virtualization@lists.linux-foundation.org, Jason Wang , Bandan Das Subject: [PATCH] virtio: virtio 1.0 cs04 spec compliance for reset Message-ID: <1459686336-29527-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mutt-Fcc: =sent X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Sun, 03 Apr 2016 12:26:25 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The spec says: after writing 0 to device_status, the driver MUST wait for a read of device_status to return 0 before reinitializing the device. Cc: stable@vger.kernel.org Signed-off-by: Michael S. Tsirkin --- drivers/virtio/virtio_pci_modern.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c index f6f28cc..e76bd91 100644 --- a/drivers/virtio/virtio_pci_modern.c +++ b/drivers/virtio/virtio_pci_modern.c @@ -17,6 +17,7 @@ * */ +#include #define VIRTIO_PCI_NO_LEGACY #include "virtio_pci_common.h" @@ -271,9 +272,13 @@ static void vp_reset(struct virtio_device *vdev) struct virtio_pci_device *vp_dev = to_vp_device(vdev); /* 0 status means a reset. */ vp_iowrite8(0, &vp_dev->common->device_status); - /* Flush out the status write, and flush in device writes, - * including MSI-X interrupts, if any. */ - vp_ioread8(&vp_dev->common->device_status); + /* After writing 0 to device_status, the driver MUST wait for a read of + * device_status to return 0 before reinitializing the device. + * This will flush out the status write, and flush in device writes, + * including MSI-X interrupts, if any. + */ + while (vp_ioread8(&vp_dev->common->device_status)) + msleep(1); /* Flush pending VQ/configuration callbacks. */ vp_synchronize_vectors(vdev); } -- MST