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 <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 3e78f4b..f9ad99c 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -113,6 +113,13 @@
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 @@
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 @@
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++)