From 64aa185d19f4e4afacd2501831049d6e615b5a84 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Tue, 16 Jul 2019 13:22:15 +0200 Subject: [PATCH 22/23] virtio-scsi: restart DMA after iothread RH-Author: Stefan Hajnoczi Message-id: <20190716132215.18503-4-stefanha@redhat.com> Patchwork-id: 89535 O-Subject: [RHEL-7.8 RHEL-7.7.z qemu-kvm-rhev PATCH 3/3] virtio-scsi: restart DMA after iothread Bugzilla: 1673546 RH-Acked-by: Paolo Bonzini RH-Acked-by: John Snow RH-Acked-by: Kevin Wolf When the 'cont' command resumes guest execution the vm change state handlers are invoked. Unfortunately there is no explicit ordering between classic qemu_add_vm_change_state_handler() callbacks. When two layers of code both use vm change state handlers, we don't control which handler runs first. virtio-scsi with iothreads hits a deadlock when a failed SCSI command is restarted and completes before the iothread is re-initialized. This patch uses the new qdev_add_vm_change_state_handler() API to guarantee that virtio-scsi's virtio change state handler executes before the SCSI bus children. This way DMA is restarted after the iothread has re-initialized. Signed-off-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf (cherry picked from commit 1a8c091c4ea5db3126514e3f7df678c9ee328802) Signed-off-by: Stefan Hajnoczi Signed-off-by: Miroslav Rezanina --- hw/scsi/scsi-bus.c | 4 ++-- hw/virtio/virtio.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c index 5905f6b..ee4c449 100644 --- a/hw/scsi/scsi-bus.c +++ b/hw/scsi/scsi-bus.c @@ -206,8 +206,8 @@ static void scsi_qdev_realize(DeviceState *qdev, Error **errp) error_propagate(errp, local_err); return; } - dev->vmsentry = qemu_add_vm_change_state_handler(scsi_dma_restart_cb, - dev); + dev->vmsentry = qdev_add_vm_change_state_handler(DEVICE(dev), + scsi_dma_restart_cb, dev); } static void scsi_qdev_unrealize(DeviceState *qdev, Error **errp) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 3492b20..08a4332 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -2306,8 +2306,8 @@ void virtio_init(VirtIODevice *vdev, const char *name, } else { vdev->config = NULL; } - vdev->vmstate = qemu_add_vm_change_state_handler(virtio_vmstate_change, - vdev); + vdev->vmstate = qdev_add_vm_change_state_handler(DEVICE(vdev), + virtio_vmstate_change, vdev); vdev->device_endian = virtio_default_endian(); vdev->use_guest_notifier_mask = true; } -- 1.8.3.1