From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753299AbaJMHpJ (ORCPT ); Mon, 13 Oct 2014 03:45:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41271 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752052AbaJMHpB (ORCPT ); Mon, 13 Oct 2014 03:45:01 -0400 Date: Mon, 13 Oct 2014 10:48:14 +0300 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Rusty Russell , virtualization@lists.linux-foundation.org, linux-scsi@vger.kernel.org, linux-s390@vger.kernel.org, v9fs-developer@lists.sourceforge.net, netdev@vger.kernel.org, kvm@vger.kernel.org, Amit Shah , Cornelia Huck , Christian Borntraeger , "David S. Miller" , Paolo Bonzini , stable@vger.kernel.org Subject: [PATCH v4 01/25] virtio_pci: fix virtio spec compliance on restore Message-ID: <1413114332-626-2-git-send-email-mst-v4@redhat.com> References: <1413114332-626-1-git-send-email-mst-v4@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1413114332-626-1-git-send-email-mst-v4@redhat.com> X-Mutt-Fcc: =sent Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On restore, virtio pci does the following: + set features + init vqs etc - device can be used at this point! + set ACKNOWLEDGE,DRIVER and DRIVER_OK status bits This is in violation of the virtio spec, which requires the following order: - ACKNOWLEDGE - DRIVER - init vqs - DRIVER_OK This behaviour will break with hypervisors that assume spec compliant behaviour. It seems like a good idea to have this patch applied to stable branches to reduce the support butden for the hypervisors. Cc: stable@vger.kernel.org Cc: Amit Shah Signed-off-by: Michael S. Tsirkin --- drivers/virtio/virtio_pci.c | 33 ++++++++++++++++++++++++++++++--- 1 file changed, 30 insertions(+), 3 deletions(-) diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index 3d1463c..add40d0 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -789,6 +789,7 @@ static int virtio_pci_restore(struct device *dev) struct pci_dev *pci_dev = to_pci_dev(dev); struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); struct virtio_driver *drv; + unsigned status = 0; int ret; drv = container_of(vp_dev->vdev.dev.driver, @@ -799,14 +800,40 @@ static int virtio_pci_restore(struct device *dev) return ret; pci_set_master(pci_dev); + /* We always start by resetting the device, in case a previous + * driver messed it up. */ + vp_reset(&vp_dev->vdev); + + /* Acknowledge that we've seen the device. */ + status |= VIRTIO_CONFIG_S_ACKNOWLEDGE; + vp_set_status(&vp_dev->vdev, status); + + /* Maybe driver failed before freeze. + * Restore the failed status, for debugging. */ + status |= vp_dev->saved_status & VIRTIO_CONFIG_S_FAILED; + vp_set_status(&vp_dev->vdev, status); + + if (!drv) + return 0; + + /* We have a driver! */ + status |= VIRTIO_CONFIG_S_DRIVER; + vp_set_status(&vp_dev->vdev, status); + vp_finalize_features(&vp_dev->vdev); - if (drv && drv->restore) + if (drv->restore) { ret = drv->restore(&vp_dev->vdev); + if (ret) { + status |= VIRTIO_CONFIG_S_FAILED; + vp_set_status(&vp_dev->vdev, status); + return ret; + } + } /* Finally, tell the device we're all set */ - if (!ret) - vp_set_status(&vp_dev->vdev, vp_dev->saved_status); + status |= VIRTIO_CONFIG_S_DRIVER_OK; + vp_set_status(&vp_dev->vdev, status); return ret; } -- MST