From b3bb62d11950eb6ac87403cacd667f84fa9495bc Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Thu, 23 Oct 2014 18:07:47 +0300 Subject: 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 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) (limited to 'drivers/virtio') 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++) -- cgit v1.2.3