On Tue, 25 Nov 2014 18:42:09 +0200
"Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote:
> virtio blk has some legacy feature bits that modern drivers
virtio-blk
> must not negotiate, but are needed for old legacy hosts
> (e.g. that dn't support virtio scsi).
(that e.g. don't support virtio-scsi)
> Allow a separate legacy feature table for such cases.
>
> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
> include/linux/virtio.h | 4 ++++
> drivers/virtio/virtio.c | 25 ++++++++++++++++++++++++-
> 2 files changed, 28 insertions(+), 1 deletion(-)
>
> @@ -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 tables for virtio v1.0 */
/* some drivers have a separate feature table for legacy virtio */
?
> + 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;
> + }
(...)
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