From 4f76617378ee97c557b526cb58d3c61eb0a9c963 Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Tue, 8 Jan 2019 15:53:03 +0100 Subject: vfio-ccw: protect the I/O region Introduce a mutex to disallow concurrent reads or writes to the I/O region. This makes sure that the data the kernel or user space see is always consistent. The same mutex will be used to protect the async region as well. Reviewed-by: Eric Farman Signed-off-by: Cornelia Huck --- drivers/s390/cio/vfio_ccw_drv.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/s390/cio/vfio_ccw_drv.c') diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c index 0b3b9de45c60..5ea0da1dd954 100644 --- a/drivers/s390/cio/vfio_ccw_drv.c +++ b/drivers/s390/cio/vfio_ccw_drv.c @@ -84,7 +84,9 @@ static void vfio_ccw_sch_io_todo(struct work_struct *work) if (is_final) cp_free(&private->cp); } + mutex_lock(&private->io_mutex); memcpy(private->io_region->irb_area, irb, sizeof(*irb)); + mutex_unlock(&private->io_mutex); if (private->io_trigger) eventfd_signal(private->io_trigger, 1); @@ -129,6 +131,7 @@ static int vfio_ccw_sch_probe(struct subchannel *sch) private->sch = sch; dev_set_drvdata(&sch->dev, private); + mutex_init(&private->io_mutex); spin_lock_irq(sch->lock); private->state = VFIO_CCW_STATE_NOT_OPER; -- cgit v1.2.3