[PATCH v7 17/46] KVM: s390: Set virtio-ccw transport revision

Michael S. Tsirkin
2014-11-30T15:11:01Z

From: Thomas Huth <thuth@linux.vnet.ibm.com>

With the new SET-VIRTIO-REVISION command of the virtio 1.0 standard, we
can now negotiate the virtio-ccw revision after setting a channel online.

Note that we don't negotiate version 1 yet.

[Cornelia Huck: reworked revision loop a bit]
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
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 | 63 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 63 insertions(+)

diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 65d0c80..f6eb47b 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -55,6 +55,7 @@ struct virtio_ccw_device {
struct ccw_device *cdev;
__u32 curr_io;
int err;
+ unsigned int revision; /* Transport revision */
wait_queue_head_t wait_q;
spinlock_t lock;
struct list_head virtqueues;
@@ -86,6 +87,15 @@ struct virtio_thinint_area {
u8 isc;
} __packed;

+struct virtio_rev_info {
+ __u16 revision;
+ __u16 length;
+ __u8 data[];
+};
+
+/* the highest virtio-ccw revision we support */
+#define VIRTIO_CCW_REV_MAX 0
+
struct virtio_ccw_vq_info {
struct virtqueue *vq;
int num;
@@ -122,6 +132,7 @@ static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
#define CCW_CMD_WRITE_STATUS 0x31
#define CCW_CMD_READ_VQ_CONF 0x32
#define CCW_CMD_SET_IND_ADAPTER 0x73
+#define CCW_CMD_SET_VIRTIO_REV 0x83

#define VIRTIO_CCW_DOING_SET_VQ 0x00010000
#define VIRTIO_CCW_DOING_RESET 0x00040000
@@ -134,6 +145,7 @@ static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
#define VIRTIO_CCW_DOING_READ_VQ_CONF 0x02000000
#define VIRTIO_CCW_DOING_SET_CONF_IND 0x04000000
#define VIRTIO_CCW_DOING_SET_IND_ADAPTER 0x08000000
+#define VIRTIO_CCW_DOING_SET_VIRTIO_REV 0x10000000
#define VIRTIO_CCW_INTPARM_MASK 0xffff0000

static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev)
@@ -933,6 +945,7 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev,
case VIRTIO_CCW_DOING_RESET:
case VIRTIO_CCW_DOING_READ_VQ_CONF:
case VIRTIO_CCW_DOING_SET_IND_ADAPTER:
+ case VIRTIO_CCW_DOING_SET_VIRTIO_REV:
vcdev->curr_io &= ~activity;
wake_up(&vcdev->wait_q);
break;
@@ -1048,6 +1061,51 @@ static int virtio_ccw_offline(struct ccw_device *cdev)
return 0;
}

+static int virtio_ccw_set_transport_rev(struct virtio_ccw_device *vcdev)
+{
+ struct virtio_rev_info *rev;
+ struct ccw1 *ccw;
+ int ret;
+
+ ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+ if (!ccw)
+ return -ENOMEM;
+ rev = kzalloc(sizeof(*rev), GFP_DMA | GFP_KERNEL);
+ if (!rev) {
+ kfree(ccw);
+ return -ENOMEM;
+ }
+
+ /* Set transport revision */
+ ccw->cmd_code = CCW_CMD_SET_VIRTIO_REV;
+ ccw->flags = 0;
+ ccw->count = sizeof(*rev);
+ ccw->cda = (__u32)(unsigned long)rev;
+
+ vcdev->revision = VIRTIO_CCW_REV_MAX;
+ do {
+ rev->revision = vcdev->revision;
+ /* none of our supported revisions carry payload */
+ rev->length = 0;
+ ret = ccw_io_helper(vcdev, ccw,
+ VIRTIO_CCW_DOING_SET_VIRTIO_REV);
+ if (ret == -EOPNOTSUPP) {
+ if (vcdev->revision == 0)
+ /*
+ * The host device does not support setting
+ * the revision: let's operate it in legacy
+ * mode.
+ */
+ ret = 0;
+ else
+ vcdev->revision--;
+ }
+ } while (ret == -EOPNOTSUPP);
+
+ kfree(ccw);
+ kfree(rev);
+ return ret;
+}

static int virtio_ccw_online(struct ccw_device *cdev)
{
@@ -1088,6 +1146,11 @@ static int virtio_ccw_online(struct ccw_device *cdev)
spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
vcdev->vdev.id.vendor = cdev->id.cu_type;
vcdev->vdev.id.device = cdev->id.cu_model;
+
+ ret = virtio_ccw_set_transport_rev(vcdev);
+ if (ret)
+ goto out_free;
+
ret = register_virtio_device(&vcdev->vdev);
if (ret) {
dev_warn(&cdev->dev, "Failed to register virtio device: %d\n",
--
MST