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FROMLIST: virtio: do not reset stateful devices on resume

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We assume that stateful devices can maintain their state while
suspended. And for this reason they don't have a freeze callback. If
such a device is reset during resume, the device state/context will be
lost on the device side. And the virtual device will stop working.

Signed-off-by: Anton Yakovlev <Anton.Yakovlev@opensynergy.com>
Signed-off-by: Mikhail Golubev <mikhail.golubev@opensynergy.com>

Bug: 180046477
Link: https://lore.kernel.org/all/20211214163249.GA253555@opensynergy.com/
Change-Id: I20410a5af8f73eebba1986965c347288ee07c0ab
Signed-off-by: Mikhail Golubev <Mikhail.Golubev@opensynergy.com>
This commit is contained in:
Anton Yakovlev
2020-09-15 13:04:55 +02:00
committed by Todd Kjos
parent 392cb940f6
commit 9180348b91
1 changed files with 8 additions and 0 deletions
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8
drivers/virtio/virtio.c
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@@ -408,6 +408,13 @@ int virtio_device_restore(struct virtio_device *dev)
struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
int ret;
/* Short path for stateful devices. Here we assume that if the device
* does not have a freeze callback, its state was not changed when
* suspended.
*/
if (drv && !drv->freeze)
goto on_config_enable;
/* We always start by resetting the device, in case a previous
* driver messed it up. */
dev->config->reset(dev);
@@ -439,6 +446,7 @@ int virtio_device_restore(struct virtio_device *dev)
/* Finally, tell the device we're all set */
virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
on_config_enable:
virtio_config_enable(dev);
return 0;