On Fri, 15 Nov 2019 03:56:12 +0100
Eric Farman <farman@xxxxxxxxxxxxx> wrote:
> From: Farhan Ali <alifm@xxxxxxxxxxxxx>
>
> Register the chp_event callback to receive channel path related
> events for the subchannels managed by vfio-ccw.
>
> Signed-off-by: Farhan Ali <alifm@xxxxxxxxxxxxx>
> Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx>
> ---
>
> Notes:
> v0->v1: [EF]
> - Add s390dbf trace
>
> drivers/s390/cio/vfio_ccw_drv.c | 44 +++++++++++++++++++++++++++++++++
> 1 file changed, 44 insertions(+)
>
> diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
> index 91989269faf1..05da1facee60 100644
> --- a/drivers/s390/cio/vfio_ccw_drv.c
> +++ b/drivers/s390/cio/vfio_ccw_drv.c
> @@ -19,6 +19,7 @@
>
> #include <asm/isc.h>
>
> +#include "chp.h"
> #include "ioasm.h"
> #include "css.h"
> #include "vfio_ccw_private.h"
> @@ -257,6 +258,48 @@ static int vfio_ccw_sch_event(struct subchannel *sch, int process)
> return rc;
> }
>
> +static int vfio_ccw_chp_event(struct subchannel *sch,
> + struct chp_link *link, int event)
> +{
> + struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
> + int mask = chp_ssd_get_mask(&sch->ssd_info, link);
> + int retry = 255;
> +
> + if (!private || !mask)
> + return 0;
> +
> + if (cio_update_schib(sch))
> + return -ENODEV;
It seems this return code is only checked by the common I/O layer for
the _OFFLINE case; still, it's probably not a bad idea, even though it
is different from what the vanilla I/O subchannel driver does.
> +
> + VFIO_CCW_MSG_EVENT(2, "%pUl (%x.%x.%04x): mask=0x%x event=%d\n",
> + mdev_uuid(private->mdev), sch->schid.cssid,
> + sch->schid.ssid, sch->schid.sch_no,
> + mask, event);
If you log only here, you're missing the case above.
> +
> + switch (event) {
> + case CHP_VARY_OFF:
> + /* Path logically turned off */
> + sch->opm &= ~mask;
> + sch->lpm &= ~mask;
> + break;
> + case CHP_OFFLINE:
> + /* Path is gone */
> + cio_cancel_halt_clear(sch, &retry);
> + break;
> + case CHP_VARY_ON:
> + /* Path logically turned on */
> + sch->opm |= mask;
> + sch->lpm |= mask;
> + break;
> + case CHP_ONLINE:
> + /* Path became available */
> + sch->lpm |= mask & sch->opm;
> + break;
> + }
Looks sane as the first round.
> +
> + return 0;
> +}
> +
> static struct css_device_id vfio_ccw_sch_ids[] = {
> { .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
> { /* end of list */ },
> @@ -274,6 +317,7 @@ static struct css_driver vfio_ccw_sch_driver = {
> .remove = vfio_ccw_sch_remove,
> .shutdown = vfio_ccw_sch_shutdown,
> .sch_event = vfio_ccw_sch_event,
> + .chp_event = vfio_ccw_chp_event,
> };
>
> static int __init vfio_ccw_debug_init(void)
