From 63a3520e29a1a68d8610315b049ccb5840fe22e9 Mon Sep 17 00:00:00 2001 From: Milan Zamazal Date: Thu, 20 Jul 2023 12:10:37 +0200 Subject: [PATCH] hw/virtio: Add a protection against duplicate vu_scmi_stop calls The QEMU CI fails in virtio-scmi test occasionally. As reported by Thomas Huth, this happens most likely when the system is loaded and it fails with the following error: qemu-system-aarch64: ../../devel/qemu/hw/pci/msix.c:659: msix_unset_vector_notifiers: Assertion `dev->msix_vector_use_notifier && dev->msix_vector_release_notifier' failed. ../../devel/qemu/tests/qtest/libqtest.c:200: kill_qemu() detected QEMU death from signal 6 (Aborted) (core dumped) As discovered by Fabiano Rosas, the cause is a duplicate invocation of msix_unset_vector_notifiers via duplicate vu_scmi_stop calls: msix_unset_vector_notifiers virtio_pci_set_guest_notifiers vu_scmi_stop vu_scmi_disconnect ... qemu_chr_write_buffer msix_unset_vector_notifiers virtio_pci_set_guest_notifiers vu_scmi_stop vu_scmi_set_status ... qemu_cleanup While vu_scmi_stop calls are protected by vhost_dev_is_started() check, it's apparently not enough. vhost-user-blk and vhost-user-gpio use an extra protection, see f5b22d06fb (vhost: recheck dev state in the vhost_migration_log routine) for the motivation. Let's use the same in vhost-user-scmi, which fixes the failure above. Fixes: a5dab090e142 ("hw/virtio: Add boilerplate for vhost-user-scmi device") Signed-off-by: Milan Zamazal Message-Id: <20230720101037.2161450-1-mzamazal@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Tested-by: Thomas Huth Reviewed-by: Fabiano Rosas --- hw/virtio/vhost-user-scmi.c | 7 +++++++ include/hw/virtio/vhost-user-scmi.h | 1 + 2 files changed, 8 insertions(+) diff --git a/hw/virtio/vhost-user-scmi.c b/hw/virtio/vhost-user-scmi.c index d386fb2df9..918bb7dcf7 100644 --- a/hw/virtio/vhost-user-scmi.c +++ b/hw/virtio/vhost-user-scmi.c @@ -63,6 +63,7 @@ static int vu_scmi_start(VirtIODevice *vdev) error_report("Error starting vhost-user-scmi: %d", ret); goto err_guest_notifiers; } + scmi->started_vu = true; /* * guest_notifier_mask/pending not used yet, so just unmask @@ -90,6 +91,12 @@ static void vu_scmi_stop(VirtIODevice *vdev) struct vhost_dev *vhost_dev = &scmi->vhost_dev; int ret; + /* vhost_dev_is_started() check in the callers is not fully reliable. */ + if (!scmi->started_vu) { + return; + } + scmi->started_vu = false; + if (!k->set_guest_notifiers) { return; } diff --git a/include/hw/virtio/vhost-user-scmi.h b/include/hw/virtio/vhost-user-scmi.h index 6175a74ebd..c90db77dd5 100644 --- a/include/hw/virtio/vhost-user-scmi.h +++ b/include/hw/virtio/vhost-user-scmi.h @@ -25,6 +25,7 @@ struct VHostUserSCMI { VirtQueue *cmd_vq; VirtQueue *event_vq; bool connected; + bool started_vu; }; #endif /* _QEMU_VHOST_USER_SCMI_H */