virtio: pci: add PM notification handlers for restore, freeze, thaw, poweroff

Handle thaw, restore and freeze notifications from the PM core.  Expose
these to individual virtio drivers that can quiesce and resume vq
operations.  For drivers not implementing the thaw() method, use the
restore method instead.

These functions also save device-specific data so that the device can be
put in pre-suspend state after resume, and disable and enable the PCI
device in the freeze and resume functions, respectively.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

drivers/virtio/virtio_pci.c

@@ -55,6 +55,10 @@ struct virtio_pci_device
 	unsigned msix_vectors;
 	/* Vectors allocated, excluding per-vq vectors if any */
 	unsigned msix_used_vectors;
+
+	/* Status saved during hibernate/restore */
+	u8 saved_status;
+
 	/* Whether we have vector per vq */
 	bool per_vq_vectors;
 };
@@ -734,9 +738,95 @@ static int virtio_pci_resume(struct device *dev)
 	return 0;
 }
 
+static int virtio_pci_freeze(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
+	struct virtio_driver *drv;
+	int ret;
+
+	drv = container_of(vp_dev->vdev.dev.driver,
+			   struct virtio_driver, driver);
+
+	ret = 0;
+	vp_dev->saved_status = vp_get_status(&vp_dev->vdev);
+	if (drv && drv->freeze)
+		ret = drv->freeze(&vp_dev->vdev);
+
+	if (!ret)
+		pci_disable_device(pci_dev);
+	return ret;
+}
+
+static int restore_common(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
+	int ret;
+
+	ret = pci_enable_device(pci_dev);
+	if (ret)
+		return ret;
+	pci_set_master(pci_dev);
+	vp_finalize_features(&vp_dev->vdev);
+
+	return ret;
+}
+
+static int virtio_pci_thaw(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
+	struct virtio_driver *drv;
+	int ret;
+
+	ret = restore_common(dev);
+	if (ret)
+		return ret;
+
+	drv = container_of(vp_dev->vdev.dev.driver,
+			   struct virtio_driver, driver);
+
+	if (drv && drv->thaw)
+		ret = drv->thaw(&vp_dev->vdev);
+	else if (drv && drv->restore)
+		ret = drv->restore(&vp_dev->vdev);
+
+	/* Finally, tell the device we're all set */
+	if (!ret)
+		vp_set_status(&vp_dev->vdev, vp_dev->saved_status);
+
+	return ret;
+}
+
+static int virtio_pci_restore(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
+	struct virtio_driver *drv;
+	int ret;
+
+	drv = container_of(vp_dev->vdev.dev.driver,
+			   struct virtio_driver, driver);
+
+	ret = restore_common(dev);
+	if (!ret && drv && drv->restore)
+		ret = drv->restore(&vp_dev->vdev);
+
+	/* Finally, tell the device we're all set */
+	if (!ret)
+		vp_set_status(&vp_dev->vdev, vp_dev->saved_status);
+
+	return ret;
+}
+
 static const struct dev_pm_ops virtio_pci_pm_ops = {
 	.suspend	= virtio_pci_suspend,
 	.resume		= virtio_pci_resume,
+	.freeze		= virtio_pci_freeze,
+	.thaw		= virtio_pci_thaw,
+	.restore	= virtio_pci_restore,
+	.poweroff	= virtio_pci_suspend,
 };
 #endif
 

include/linux/virtio.h

@@ -94,6 +94,11 @@ struct virtio_driver {
 	int (*probe)(struct virtio_device *dev);
 	void (*remove)(struct virtio_device *dev);
 	void (*config_changed)(struct virtio_device *dev);
+#ifdef CONFIG_PM
+	int (*freeze)(struct virtio_device *dev);
+	int (*thaw)(struct virtio_device *dev);
+	int (*restore)(struct virtio_device *dev);
+#endif
 };
 
 int register_virtio_driver(struct virtio_driver *drv);