[PATCH v2 0/9] Move vfio_ccw to the new mdev API

[Jason Gunthorpe]

On Mon, Sep 13, 2021 at 01:40:34PM -0400, Eric Farman wrote:
> On Thu, 2021-09-09 at 16:38 -0300, Jason Gunthorpe wrote:
> > This addresses Cornelia's remark on the earlier patch that ccw has a
> > confusing lifecycle. While it doesn't seem like the original attempt
> > was
> > functionally wrong, the result can be made better with a lot of
> > further
> > work.
> 
> I thought I'd take a stab at seeing how this works with the hardware
> before looking at the code much. git couldn't apply patches 1, 6, or 9
> to 5.15-rc1, but I was able to hand-fit them into place. 

Oh? Thats odd, I had no remarks from git when rebasing onto
v5.15-rc1..

Maybe this is a situation where you need "b4 am --prep-3way" ...

> [   64.585462] Call Trace:
> [   64.585464]  [<0000000000000002>] 0x2 
> [   64.585467] ([<000003ff80179d74>] vfio_ccw_mdev_ioctl+0x84/0x318
> [vfio_ccw])
> [   64.585476]  [<00000000bb7adda6>] __s390x_sys_ioctl+0xbe/0x100 
> [   64.585481]  [<00000000bbfbf5e4>] __do_syscall+0x1bc/0x1e8 
> [   64.585488]  [<00000000bbfcc8d8>] system_call+0x78/0xa0 

I think it is this:

diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index df1490943b20ec..5ea392959c0711 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -441,6 +441,7 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
 		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_error,
 		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_error,
 		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_disabled_irq,
+		[VFIO_CCW_EVENT_OPEN]		= fsm_nop,
 		[VFIO_CCW_EVENT_CLOSE]		= fsm_nop,
 	},
 	[VFIO_CCW_STATE_CLOSED] = {

I rebased it and fixed it up here:

https://github.com/jgunthorpe/linux/tree/vfio_ccw

Can you try again?

Thanks,
Jason