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Currently there is no way for user to set what features the driver should obey or not, it is hard wired in the code. In order to be able to debug the device behavior in case some feature is disabled, introduce a debugfs infrastructure with couple of files allowing user to see what features the device advertises and to set filter for features used by driver. Example: $cat /sys/bus/virtio/devices/virtio0/features 1110010111111111111101010000110010000000100000000000000000000000 $ echo "5" >/sys/kernel/debug/virtio/virtio0/filter_feature_add $ cat /sys/kernel/debug/virtio/virtio0/filter_features 5 $ echo "virtio0" > /sys/bus/virtio/drivers/virtio_net/unbind $ echo "virtio0" > /sys/bus/virtio/drivers/virtio_net/bind $ cat /sys/bus/virtio/devices/virtio0/features 1110000111111111111101010000110010000000100000000000000000000000 Note that sysfs "features" now already exists, this patch does not touch it. Signed-off-by: Jiri Pirko <jiri@nvidia.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
115 lines
3.2 KiB
C
115 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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#include <linux/virtio.h>
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#include <linux/virtio_config.h>
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#include <linux/debugfs.h>
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static struct dentry *virtio_debugfs_dir;
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static int virtio_debug_device_features_show(struct seq_file *s, void *data)
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{
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struct virtio_device *dev = s->private;
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u64 device_features;
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unsigned int i;
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device_features = dev->config->get_features(dev);
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for (i = 0; i < BITS_PER_LONG_LONG; i++) {
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if (device_features & (1ULL << i))
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seq_printf(s, "%u\n", i);
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}
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return 0;
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}
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DEFINE_SHOW_ATTRIBUTE(virtio_debug_device_features);
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static int virtio_debug_filter_features_show(struct seq_file *s, void *data)
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{
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struct virtio_device *dev = s->private;
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unsigned int i;
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for (i = 0; i < BITS_PER_LONG_LONG; i++) {
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if (dev->debugfs_filter_features & (1ULL << i))
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seq_printf(s, "%u\n", i);
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}
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return 0;
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}
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DEFINE_SHOW_ATTRIBUTE(virtio_debug_filter_features);
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static int virtio_debug_filter_features_clear(void *data, u64 val)
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{
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struct virtio_device *dev = data;
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if (val == 1)
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dev->debugfs_filter_features = 0;
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return 0;
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}
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DEFINE_DEBUGFS_ATTRIBUTE(virtio_debug_filter_features_clear_fops, NULL,
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virtio_debug_filter_features_clear, "%llu\n");
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static int virtio_debug_filter_feature_add(void *data, u64 val)
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{
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struct virtio_device *dev = data;
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if (val >= BITS_PER_LONG_LONG)
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return -EINVAL;
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dev->debugfs_filter_features |= BIT_ULL_MASK(val);
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return 0;
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}
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DEFINE_DEBUGFS_ATTRIBUTE(virtio_debug_filter_feature_add_fops, NULL,
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virtio_debug_filter_feature_add, "%llu\n");
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static int virtio_debug_filter_feature_del(void *data, u64 val)
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{
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struct virtio_device *dev = data;
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if (val >= BITS_PER_LONG_LONG)
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return -EINVAL;
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dev->debugfs_filter_features &= ~BIT_ULL_MASK(val);
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return 0;
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}
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DEFINE_DEBUGFS_ATTRIBUTE(virtio_debug_filter_feature_del_fops, NULL,
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virtio_debug_filter_feature_del, "%llu\n");
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void virtio_debug_device_init(struct virtio_device *dev)
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{
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dev->debugfs_dir = debugfs_create_dir(dev_name(&dev->dev),
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virtio_debugfs_dir);
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debugfs_create_file("device_features", 0400, dev->debugfs_dir, dev,
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&virtio_debug_device_features_fops);
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debugfs_create_file("filter_features", 0400, dev->debugfs_dir, dev,
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&virtio_debug_filter_features_fops);
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debugfs_create_file("filter_features_clear", 0200, dev->debugfs_dir, dev,
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&virtio_debug_filter_features_clear_fops);
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debugfs_create_file("filter_feature_add", 0200, dev->debugfs_dir, dev,
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&virtio_debug_filter_feature_add_fops);
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debugfs_create_file("filter_feature_del", 0200, dev->debugfs_dir, dev,
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&virtio_debug_filter_feature_del_fops);
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}
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EXPORT_SYMBOL_GPL(virtio_debug_device_init);
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void virtio_debug_device_filter_features(struct virtio_device *dev)
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{
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dev->features &= ~dev->debugfs_filter_features;
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}
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EXPORT_SYMBOL_GPL(virtio_debug_device_filter_features);
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void virtio_debug_device_exit(struct virtio_device *dev)
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{
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debugfs_remove_recursive(dev->debugfs_dir);
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}
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EXPORT_SYMBOL_GPL(virtio_debug_device_exit);
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void virtio_debug_init(void)
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{
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virtio_debugfs_dir = debugfs_create_dir("virtio", NULL);
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}
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EXPORT_SYMBOL_GPL(virtio_debug_init);
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void virtio_debug_exit(void)
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{
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debugfs_remove_recursive(virtio_debugfs_dir);
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}
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EXPORT_SYMBOL_GPL(virtio_debug_exit);
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