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virtio/s390: support READ_STATUS command for virtio-ccw

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As virtio-1 introduced the possibility of the device manipulating the
status byte, revision 2 of the virtio-ccw transport introduced a means
of getting the status byte from the device via READ_STATUS. Let's wire
it up for revisions >= 2 and fall back to returning the stored status
byte if not supported.

Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
This commit is contained in:
Pierre Morel 2015-08-28 11:09:32 +02:00 committed by Michael S. Tsirkin
parent 47a4c49af6
commit 7d3ce5ab94
1 changed files with 25 additions and 0 deletions
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25
drivers/s390/virtio/virtio_ccw.c
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@ -145,6 +145,7 @@ static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
#define CCW_CMD_WRITE_CONF 0x21
#define CCW_CMD_WRITE_STATUS 0x31
#define CCW_CMD_READ_VQ_CONF 0x32
#define CCW_CMD_READ_STATUS 0x72
#define CCW_CMD_SET_IND_ADAPTER 0x73
#define CCW_CMD_SET_VIRTIO_REV 0x83
@ -160,6 +161,7 @@ static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
#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_DOING_READ_STATUS 0x20000000
#define VIRTIO_CCW_INTPARM_MASK 0xffff0000
static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev)
@ -892,6 +894,28 @@ out_free:
static u8 virtio_ccw_get_status(struct virtio_device *vdev)
{
struct virtio_ccw_device *vcdev = to_vc_device(vdev);
u8 old_status = *vcdev->status;
struct ccw1 *ccw;
if (vcdev->revision < 1)
return *vcdev->status;
ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
if (!ccw)
return old_status;
ccw->cmd_code = CCW_CMD_READ_STATUS;
ccw->flags = 0;
ccw->count = sizeof(*vcdev->status);
ccw->cda = (__u32)(unsigned long)vcdev->status;
ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_STATUS);
/*
* If the channel program failed (should only happen if the device
* was hotunplugged, and then we clean up via the machine check
* handler anyway), vcdev->status was not overwritten and we just
* return the old status, which is fine.
*/
kfree(ccw);
return *vcdev->status;
}
@ -987,6 +1011,7 @@ static void virtio_ccw_check_activity(struct virtio_ccw_device *vcdev,
case VIRTIO_CCW_DOING_READ_CONFIG:
case VIRTIO_CCW_DOING_WRITE_CONFIG:
case VIRTIO_CCW_DOING_WRITE_STATUS:
case VIRTIO_CCW_DOING_READ_STATUS:
case VIRTIO_CCW_DOING_SET_VQ:
case VIRTIO_CCW_DOING_SET_IND:
case VIRTIO_CCW_DOING_SET_CONF_IND: