Commit 43c590cb authored by Johannes Berg's avatar Johannes Berg Committed by Richard Weinberger
Browse files

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: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent 68f5d3f3

arch/um/drivers/virt-pci.c

+10 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/logic_iomem.h>

#include <linux/irqdomain.h>

#include <linux/virtio_pcidev.h>

#include <linux/virtio-uml.h>

#include <linux/delay.h>

#include <linux/msi.h>

#include <asm/unaligned.h>
@@ -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:

arch/um/drivers/virtio_uml.c

+30 −10
Original line number Diff line number Diff line
@@ -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)
@@ -1302,6 +1316,8 @@ 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);



	if (!vu_dev->no_vq_suspend) {

		struct virtqueue *vq;



		virtio_device_for_each_vq((&vu_dev->vdev), vq) {
@@ -1310,6 +1326,7 @@ static int virtio_uml_suspend(struct platform_device *pdev, pm_message_t state) 
			info->suspended = true;

			vhost_user_set_vring_enable(vu_dev, vq->index, false);

		}

	}



	if (!device_may_wakeup(&vu_dev->vdev.dev)) {

		vu_dev->suspended = true;
@@ -1322,6 +1339,8 @@ 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);



	if (!vu_dev->no_vq_suspend) {

		struct virtqueue *vq;



		virtio_device_for_each_vq((&vu_dev->vdev), vq) {
@@ -1330,6 +1349,7 @@ static int virtio_uml_resume(struct platform_device *pdev) 
			info->suspended = false;

			vhost_user_set_vring_enable(vu_dev, vq->index, true);

		}

	}



	vu_dev->suspended = false;

arch/um/include/linux/virtio-uml.h

0 → 100644
+13 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

/*

 * Copyright (C) 2021 Intel Corporation

 * Author: Johannes Berg <johannes@sipsolutions.net>

 */



#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__ */