From ed7ac37fde33ccd84e4bd2b9363c191f925364c7 Mon Sep 17 00:00:00 2001
From: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Date: Tue, 21 Jun 2022 13:06:20 +0200
Subject: [PATCH] virtio_mmio: Add missing PM calls to freeze/restore
Git-commit: ed7ac37fde33ccd84e4bd2b9363c191f925364c7
Patch-mainline: v5.19-rc5
References: git-fixes

Most virtio drivers provide freeze/restore callbacks to finish up
device usage before suspend and to reinitialize the virtio device after
resume. However, these callbacks are currently only called when using
virtio_pci. virtio_mmio does not have any PM ops defined.

This causes problems for example after suspend to disk (hibernation),
since the virtio devices might lose their state after the VMM is
restarted. Calling virtio_device_freeze()/restore() ensures that
the virtio devices are re-initialized correctly.

Fix this by implementing the dev_pm_ops for virtio_mmio,
similar to virtio_pci_common.

Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Message-id: <20220621110621.3638025-2-stephan.gerhold@kernkonzept.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/virtio/virtio_mmio.c |   23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -62,6 +62,7 @@
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/pm.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/virtio.h>
@@ -543,6 +544,25 @@ static const struct virtio_config_ops vi
 	.get_shm_region = vm_get_shm_region,
 };
 
+#ifdef CONFIG_PM_SLEEP
+static int virtio_mmio_freeze(struct device *dev)
+{
+	struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
+
+	return virtio_device_freeze(&vm_dev->vdev);
+}
+
+static int virtio_mmio_restore(struct device *dev)
+{
+	struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
+
+	return virtio_device_restore(&vm_dev->vdev);
+}
+
+static const struct dev_pm_ops virtio_mmio_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(virtio_mmio_freeze, virtio_mmio_restore)
+};
+#endif
 
 static void virtio_mmio_release_dev(struct device *_d)
 {
@@ -786,6 +806,9 @@ static struct platform_driver virtio_mmi
 		.name	= "virtio-mmio",
 		.of_match_table	= virtio_mmio_match,
 		.acpi_match_table = ACPI_PTR(virtio_mmio_acpi_match),
+#ifdef CONFIG_PM_SLEEP
+		.pm	= &virtio_mmio_pm_ops,
+#endif
 	},
 };