On Fri, 17 Apr 2020 04:34:36 +0200
Eric Farman <far...@linux.ibm.com> wrote:
> From: Farhan Ali <al...@linux.ibm.com>
>
> The schib region can be used to obtain the latest SCHIB from the host
> passthrough subchannel. Since the guest SCHIB is virtualized,
> we currently only update the path related information so that the
> guest is aware of any path related changes when it issues the
> 'stsch' instruction.
>
> Signed-off-by: Farhan Ali <al...@linux.ibm.com>
> Signed-off-by: Eric Farman <far...@linux.ibm.com>
> ---
>
> Notes:
> v1->v2:
> - Remove silly variable intialization, and add a block comment,
> to css_do_stsch() [CH]
> - Add a TODO statement to s390_ccw_store(), for myself to sort
> out while we go over kernel code more closely [CH/EF]
> - In vfio_ccw_handle_store(),
> - Set schib pointer once region is determined to be non-NULL [CH]
> - Return cc=0 if pread() fails, and log an error [CH]
>
> v0->v1: [EF]
> - Change various incarnations of "update chp status" to
> "handle_store", to reflect the STSCH instruction that will
> drive this code
> - Remove temporary variable for casting/testing purposes in
> s390_ccw_store(), and add a block comment of WHY its there.
> - Add a few comments to vfio_ccw_handle_store()
>
> hw/s390x/css.c | 13 ++++++--
> hw/s390x/s390-ccw.c | 28 +++++++++++++++++
> hw/vfio/ccw.c | 63 +++++++++++++++++++++++++++++++++++++
> include/hw/s390x/css.h | 3 +-
> include/hw/s390x/s390-ccw.h | 1 +
> target/s390x/ioinst.c | 3 +-
> 6 files changed, 106 insertions(+), 5 deletions(-)
>
> +IOInstEnding s390_ccw_store(SubchDev *sch)
> +{
> + S390CCWDeviceClass *cdc = NULL;
> + int ret = IOINST_CC_EXPECTED;
> +
> + /*
> + * This only applies to passthrough devices, so we can't unconditionally
> + * set this variable like we would for halt/clear.
> + *
> + * TODO from Conny on v1:
> + * "We have a generic ccw_cb in the subchannel structure for ccw
> + * interpretation; would it make sense to add a generic callback
> + * for stsch there as well?
> + *
> + * "(This works fine, though. Might want to add the check for
> + * halt/clear as well, but that might be a bit overkill.)"
Do you plan to look into that for the next version? If not, don't feel
pressured.
> + */
> + if (object_dynamic_cast(OBJECT(sch->driver_data), TYPE_S390_CCW)) {
> + cdc = S390_CCW_DEVICE_GET_CLASS(sch->driver_data);
> + }
> +
> + if (cdc && cdc->handle_store) {
> + ret = cdc->handle_store(sch);
> + }
> +
> + return ret;
> +}
> +
> static void s390_ccw_get_dev_info(S390CCWDevice *cdev,
> char *sysfsdev,
> Error **errp)
Generally, looks sane.
