Messages in this thread Patch in this message | | | Date | Tue, 14 Dec 2021 17:33:05 +0100 | From | Mikhail Golubev <> | Subject | [RFC PATCH] virtio: do not reset stateful devices on resume |
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From: Anton Yakovlev <Anton.Yakovlev@opensynergy.com>
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> --- drivers/virtio/virtio.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index 236081afe9a2..defa15b56eb8 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -472,6 +472,13 @@ 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); @@ -503,6 +510,7 @@ 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; -- 2.34.1
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