From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: [PATCHv2] qemu-kvm: fix crash on reboot with vhost-net Date: Wed, 28 Apr 2010 12:27:38 +0300 Message-ID: <20100428092738.GA32184@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org To: amit.shah@redhat.com, quintela@redhat.com, kraxel@redhat.com Return-path: Received: from mx1.redhat.com ([209.132.183.28]:49174 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750840Ab0D1KTK (ORCPT ); Wed, 28 Apr 2010 06:19:10 -0400 Received: from int-mx05.intmail.prod.int.phx2.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.18]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o3S9WAv5008044 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 28 Apr 2010 05:32:10 -0400 Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: When vhost-net is disabled on reboot, we set msix mask notifier to NULL to disable further mask/unmask notifications. Code currently tries to pass this NULL to notifier, leading to a crash. The right thing to do is to add explicit APIs to enable/disable notifications. Now when disabling notifications: - if vector is masked, we don't need to notify backend, just disable future notifications - if vector is unmasked, invoke callback to unassign backend, then disable future notifications This patch also polls notifier before closing it, to make sure we don't lose events if poll callback didn't have time to run. Signed-off-by: Michael S. Tsirkin --- Changes from v1: Separate APIs to set and unset notifiers Test and clear notifier before destroying it hw/msix.c | 40 +++++++++++++++++++++++++++++++++++----- hw/msix.h | 1 + hw/virtio-pci.c | 7 +++++-- 3 files changed, 41 insertions(+), 7 deletions(-) diff --git a/hw/msix.c b/hw/msix.c index 3ec8805..8f9a621 100644 --- a/hw/msix.c +++ b/hw/msix.c @@ -609,14 +609,44 @@ void msix_unuse_all_vectors(PCIDevice *dev) int msix_set_mask_notifier(PCIDevice *dev, unsigned vector, void *opaque) { + int r; + if (vector >= dev->msix_entries_nr || !dev->msix_entry_used[vector]) + return 0; + + assert(dev->msix_mask_notifier); + assert(opaque); + assert(!dev->msix_mask_notifier_opaque[vector]); + + if (msix_is_masked(dev, vector)) { + return 0; + } + r = dev->msix_mask_notifier(dev, vector, opaque, + msix_is_masked(dev, vector)); + if (r < 0) { + return r; + } + dev->msix_mask_notifier_opaque[vector] = opaque; + return r; +} + +int msix_unset_mask_notifier(PCIDevice *dev, unsigned vector) +{ int r = 0; if (vector >= dev->msix_entries_nr || !dev->msix_entry_used[vector]) return 0; - if (dev->msix_mask_notifier) - r = dev->msix_mask_notifier(dev, vector, opaque, - msix_is_masked(dev, vector)); - if (r >= 0) - dev->msix_mask_notifier_opaque[vector] = opaque; + assert(dev->msix_mask_notifier); + assert(dev->msix_mask_notifier_opaque[vector]); + + if (msix_is_masked(dev, vector)) { + return 0; + } + r = dev->msix_mask_notifier(dev, vector, + dev->msix_mask_notifier_opaque[vector], + msix_is_masked(dev, vector)); + if (r < 0) { + return r; + } + dev->msix_mask_notifier_opaque[vector] = NULL; return r; } diff --git a/hw/msix.h b/hw/msix.h index f167231..6b21ffb 100644 --- a/hw/msix.h +++ b/hw/msix.h @@ -34,4 +34,5 @@ void msix_reset(PCIDevice *dev); extern int msix_supported; int msix_set_mask_notifier(PCIDevice *dev, unsigned vector, void *opaque); +int msix_unset_mask_notifier(PCIDevice *dev, unsigned vector); #endif diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c index 99a588c..c4bc633 100644 --- a/hw/virtio-pci.c +++ b/hw/virtio-pci.c @@ -462,10 +462,13 @@ static int virtio_pci_set_guest_notifier(void *opaque, int n, bool assign) msix_set_mask_notifier(&proxy->pci_dev, virtio_queue_vector(proxy->vdev, n), vq); } else { - msix_set_mask_notifier(&proxy->pci_dev, - virtio_queue_vector(proxy->vdev, n), NULL); + msix_unset_mask_notifier(&proxy->pci_dev, + virtio_queue_vector(proxy->vdev, n)); qemu_set_fd_handler(event_notifier_get_fd(notifier), NULL, NULL, NULL); + /* Test and clear notifier before closing it, + * in case poll callback didn't have time to run. */ + virtio_pci_guest_notifier_read(vq); event_notifier_cleanup(notifier); } -- 1.7.1.rc1.22.g3163