From b3bb62d11950eb6ac87403cacd667f84fa9495bc Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Thu, 23 Oct 2014 18:07:47 +0300 Subject: [PATCH] virtio: add legacy feature table support virtio-blk has some legacy feature bits that modern drivers must not negotiate, but are needed for old legacy hosts (that e.g. don't support virtio-scsi). Allow a separate legacy feature table for such cases. Signed-off-by: Michael S. Tsirkin Reviewed-by: Cornelia Huck --- drivers/virtio/virtio.c | 25 ++++++++++++++++++++++++- include/linux/virtio.h | 4 ++++ 2 files changed, 28 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index 3e78f4bcfa8e..f9ad99c8b352 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -113,6 +113,13 @@ void virtio_check_driver_offered_feature(const struct virtio_device *vdev, for (i = 0; i < drv->feature_table_size; i++) if (drv->feature_table[i] == fbit) return; + + if (drv->feature_table_legacy) { + for (i = 0; i < drv->feature_table_size_legacy; i++) + if (drv->feature_table_legacy[i] == fbit) + return; + } + BUG(); } EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature); @@ -161,6 +168,7 @@ static int virtio_dev_probe(struct device *_d) struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); u64 device_features; u64 driver_features; + u64 driver_features_legacy; unsigned status; /* We have a driver! */ @@ -177,7 +185,22 @@ static int virtio_dev_probe(struct device *_d) driver_features |= (1ULL << f); } - dev->features = driver_features & device_features; + /* Some drivers have a separate feature table for virtio v1.0 */ + if (drv->feature_table_legacy) { + driver_features_legacy = 0; + for (i = 0; i < drv->feature_table_size_legacy; i++) { + unsigned int f = drv->feature_table_legacy[i]; + BUG_ON(f >= 64); + driver_features_legacy |= (1ULL << f); + } + } else { + driver_features_legacy = driver_features; + } + + if (driver_features & device_features & (1ULL << VIRTIO_F_VERSION_1)) + dev->features = driver_features & device_features; + else + dev->features = driver_features_legacy & device_features; /* Transport features always preserved to pass to finalize_features. */ for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) diff --git a/include/linux/virtio.h b/include/linux/virtio.h index d6359a5d5d4e..f70411eb9d27 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -130,6 +130,8 @@ int virtio_device_restore(struct virtio_device *dev); * @id_table: the ids serviced by this driver. * @feature_table: an array of feature numbers supported by this driver. * @feature_table_size: number of entries in the feature table array. + * @feature_table_legacy: same as feature_table but when working in legacy mode. + * @feature_table_size_legacy: number of entries in feature table legacy array. * @probe: the function to call when a device is found. Returns 0 or -errno. * @remove: the function to call when a device is removed. * @config_changed: optional function to call when the device configuration @@ -140,6 +142,8 @@ struct virtio_driver { const struct virtio_device_id *id_table; const unsigned int *feature_table; unsigned int feature_table_size; + const unsigned int *feature_table_legacy; + unsigned int feature_table_size_legacy; int (*probe)(struct virtio_device *dev); void (*scan)(struct virtio_device *dev); void (*remove)(struct virtio_device *dev); -- GitLab