From 43c590cb86665be702c0af0231a10ec813df9cfd Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 5 Mar 2021 13:19:59 +0100 Subject: [PATCH] um: virtio/pci: enable suspend/resume The UM virtual PCI devices currently cannot be suspended properly since the virtio driver already disables VQs well before the PCI bus's suspend_noirq wants to complete the transition by writing to PCI config space. After trying around for a long time with moving the devices on the DPM list, trying to create dependencies between them, etc. I gave up and instead added UML specific cross-driver API that lets the virt-pci code enable not suspending/resuming VQs for its devices. This then allows the PCI bus suspend_noirq to still talk to the device, and suspend/resume works properly. Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger --- arch/um/drivers/virt-pci.c | 10 ++++++++ arch/um/drivers/virtio_uml.c | 40 ++++++++++++++++++++++-------- arch/um/include/linux/virtio-uml.h | 13 ++++++++++ 3 files changed, 53 insertions(+), 10 deletions(-) create mode 100644 arch/um/include/linux/virtio-uml.h diff --git a/arch/um/drivers/virt-pci.c b/arch/um/drivers/virt-pci.c index dd85f36197aa..0b802834f40a 100644 --- a/arch/um/drivers/virt-pci.c +++ b/arch/um/drivers/virt-pci.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -134,6 +135,9 @@ static int um_pci_send_cmd(struct um_pci_device *dev, if (completed == HANDLE_NO_FREE(cmd)) break; + if (completed && !HANDLE_IS_NO_FREE(completed)) + kfree(completed); + if (WARN_ONCE(virtqueue_is_broken(dev->cmd_vq) || ++delay_count > UM_VIRT_PCI_MAXDELAY, "um virt-pci delay: %d", delay_count)) { @@ -550,6 +554,12 @@ static int um_pci_virtio_probe(struct virtio_device *vdev) device_set_wakeup_enable(&vdev->dev, true); + /* + * In order to do suspend-resume properly, don't allow VQs + * to be suspended. + */ + virtio_uml_set_no_vq_suspend(vdev, true); + um_pci_rescan(); return 0; error: diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c index 91ddf74ca888..4412d6febade 100644 --- a/arch/um/drivers/virtio_uml.c +++ b/arch/um/drivers/virtio_uml.c @@ -56,6 +56,7 @@ struct virtio_uml_device { u8 status; u8 registered:1; u8 suspended:1; + u8 no_vq_suspend:1; u8 config_changed_irq:1; uint64_t vq_irq_vq_map; @@ -1098,6 +1099,19 @@ static void virtio_uml_release_dev(struct device *d) kfree(vu_dev); } +void virtio_uml_set_no_vq_suspend(struct virtio_device *vdev, + bool no_vq_suspend) +{ + struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev); + + if (WARN_ON(vdev->config != &virtio_uml_config_ops)) + return; + + vu_dev->no_vq_suspend = no_vq_suspend; + dev_info(&vdev->dev, "%sabled VQ suspend\n", + no_vq_suspend ? "dis" : "en"); +} + /* Platform device */ static int virtio_uml_probe(struct platform_device *pdev) @@ -1302,13 +1316,16 @@ MODULE_DEVICE_TABLE(of, virtio_uml_match); static int virtio_uml_suspend(struct platform_device *pdev, pm_message_t state) { struct virtio_uml_device *vu_dev = platform_get_drvdata(pdev); - struct virtqueue *vq; - virtio_device_for_each_vq((&vu_dev->vdev), vq) { - struct virtio_uml_vq_info *info = vq->priv; + if (!vu_dev->no_vq_suspend) { + struct virtqueue *vq; - info->suspended = true; - vhost_user_set_vring_enable(vu_dev, vq->index, false); + virtio_device_for_each_vq((&vu_dev->vdev), vq) { + struct virtio_uml_vq_info *info = vq->priv; + + info->suspended = true; + vhost_user_set_vring_enable(vu_dev, vq->index, false); + } } if (!device_may_wakeup(&vu_dev->vdev.dev)) { @@ -1322,13 +1339,16 @@ static int virtio_uml_suspend(struct platform_device *pdev, pm_message_t state) static int virtio_uml_resume(struct platform_device *pdev) { struct virtio_uml_device *vu_dev = platform_get_drvdata(pdev); - struct virtqueue *vq; - virtio_device_for_each_vq((&vu_dev->vdev), vq) { - struct virtio_uml_vq_info *info = vq->priv; + if (!vu_dev->no_vq_suspend) { + struct virtqueue *vq; - info->suspended = false; - vhost_user_set_vring_enable(vu_dev, vq->index, true); + virtio_device_for_each_vq((&vu_dev->vdev), vq) { + struct virtio_uml_vq_info *info = vq->priv; + + info->suspended = false; + vhost_user_set_vring_enable(vu_dev, vq->index, true); + } } vu_dev->suspended = false; diff --git a/arch/um/include/linux/virtio-uml.h b/arch/um/include/linux/virtio-uml.h new file mode 100644 index 000000000000..2f652fa90f04 --- /dev/null +++ b/arch/um/include/linux/virtio-uml.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2021 Intel Corporation + * Author: Johannes Berg + */ + +#ifndef __VIRTIO_UML_H__ +#define __VIRTIO_UML_H__ + +void virtio_uml_set_no_vq_suspend(struct virtio_device *vdev, + bool no_vq_suspend); + +#endif /* __VIRTIO_UML_H__ */