On 01/21/2019 10:18 AM, Cornelia Huck wrote:
On Mon, 21 Jan 2019 09:54:09 -0500
Farhan Ali <alifm@xxxxxxxxxxxxx> wrote:
This check is unecessary as we already have the vfio state machine
to handle I/O requests.
On the other hand, this check returns incorrect information to
userspace if the state of the subchannel is not idle. For example
if the state is busy and new I/O request comes in, this will return
an EACCES, whereas we should return EBUSY.
Signed-off-by: Farhan Ali <alifm@xxxxxxxxxxxxx>
---
drivers/s390/cio/vfio_ccw_ops.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index f673e10..3fdcc6d 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -193,8 +193,6 @@ static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev,
return -EINVAL;
private = dev_get_drvdata(mdev_parent_dev(mdev));
- if (private->state != VFIO_CCW_STATE_IDLE)
- return -EACCES;
region = private->io_region;
if (copy_from_user((void *)region + *ppos, buf, count))
Hm, the patchset for halt/clear handling I recently posted changes this
to a check for NOT_OPER || STANDBY. What do you think of that option?
I am concerned with the return code that we send userspace. With the
state machines we return an EIO for NOT_OPER or STANDBY, but we return
EACCES in the early check. QEMU on an EACCES returns a 'not_oper' to the
guest and for EIO will inject an interrupt.
I believe we should try to keep it consistent to make debugging errors
easier :)
