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authorMichael S. Tsirkin <mst@redhat.com>2014-10-23 18:07:47 +0300
committerMichael S. Tsirkin <mst@redhat.com>2014-12-09 12:05:26 +0200
commitb3bb62d11950eb6ac87403cacd667f84fa9495bc (patch)
treef3aee72f5e622722d19c484c7f5925990e97cffb /drivers/virtio
parentc102659d690d382171bd2e40f35c5c811f0cdcac (diff)
downloadlinux-b3bb62d11950eb6ac87403cacd667f84fa9495bc.tar.bz2
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>
Diffstat (limited to 'drivers/virtio')
-rw-r--r--drivers/virtio/virtio.c25
1 files changed, 24 insertions, 1 deletions
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++)