From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753338AbaJ0TDE (ORCPT ); Mon, 27 Oct 2014 15:03:04 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:52655 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753300AbaJ0TC7 (ORCPT ); Mon, 27 Oct 2014 15:02:59 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Amit Shah , "Michael S. Tsirkin" , Rusty Russell , Kamal Mostafa Subject: [PATCH 3.13 098/105] virtio_pci: fix virtio spec compliance on restore Date: Mon, 27 Oct 2014 11:57:13 -0700 Message-Id: <1414436240-13879-99-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1414436240-13879-1-git-send-email-kamal@canonical.com> References: <1414436240-13879-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11.10 -stable review patch. If anyone has any objections, please let me know. ------------------ From: "Michael S. Tsirkin" commit 6fbc198cf623944ab60a1db6d306a4d55cdd820d upstream. 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: Amit Shah Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell Signed-off-by: Kamal Mostafa --- 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 a37c699..a516842 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -793,6 +793,7 @@ 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, @@ -803,14 +804,40 @@ 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; } -- 1.9.1