[PATCH v5 05/45] virtio_ccw: add support for 64 bit features.

Michael S. Tsirkin
2014-11-27T12:30:28Z

Negotiate full 64 bit features.
Change u32 to u64, make sure to use 1ULL everywhere.

Note: devices guarantee that VERSION_1 is clear unless
revision 1 is negotiated.

Based on patches by Rusty, Thomas Huth and Cornelia.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
drivers/s390/kvm/virtio_ccw.c | 30 +++++++++++++++++++++++-------
1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 244d611..abba04d 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -664,7 +664,8 @@ static u64 virtio_ccw_get_features(struct virtio_device *vdev)
{
struct virtio_ccw_device *vcdev = to_vc_device(vdev);
struct virtio_feature_desc *features;
- int ret, rc;
+ int ret;
+ u64 rc;
struct ccw1 *ccw;

ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
@@ -677,7 +678,6 @@ static u64 virtio_ccw_get_features(struct virtio_device *vdev)
goto out_free;
}
/* Read the feature bits from the host. */
- /* TODO: Features > 32 bits */
features->index = 0;
ccw->cmd_code = CCW_CMD_READ_FEAT;
ccw->flags = 0;
@@ -691,6 +691,16 @@ static u64 virtio_ccw_get_features(struct virtio_device *vdev)

rc = le32_to_cpu(features->features);

+ /* Read second half feature bits from the host. */
+ features->index = 1;
+ ccw->cmd_code = CCW_CMD_READ_FEAT;
+ ccw->flags = 0;
+ ccw->count = sizeof(*features);
+ ccw->cda = (__u32)(unsigned long)features;
+ ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_FEAT);
+ if (ret == 0)
+ rc |= (u64)le32_to_cpu(features->features) << 32;
+
out_free:
kfree(features);
kfree(ccw);
@@ -714,12 +724,18 @@ static void virtio_ccw_finalize_features(struct virtio_device *vdev)
/* Give virtio_ring a chance to accept features. */
vring_transport_features(vdev);

- /* Make sure we don't have any features > 32 bits! */
- BUG_ON((u32)vdev->features != vdev->features);
-
features->index = 0;
- features->features = cpu_to_le32(vdev->features);
- /* Write the feature bits to the host. */
+ features->features = cpu_to_le32((u32)vdev->features);
+ /* Write the first half of the feature bits to the host. */
+ ccw->cmd_code = CCW_CMD_WRITE_FEAT;
+ ccw->flags = 0;
+ ccw->count = sizeof(*features);
+ ccw->cda = (__u32)(unsigned long)features;
+ ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
+
+ features->index = 1;
+ features->features = cpu_to_le32(vdev->features >> 32);
+ /* Write the second half of the feature bits to the host. */
ccw->cmd_code = CCW_CMD_WRITE_FEAT;
ccw->flags = 0;
ccw->count = sizeof(*features);
--
MST