Re: [RFC v2 5/5] vfio-ccw: Update documentation for csch/hsch

Farhan Ali
2019-07-09T12:48:08Z

On 07/09/2019 06:14 AM, Cornelia Huck wrote:
> On Mon, 8 Jul 2019 16:10:38 -0400
> Farhan Ali <alifm@linux.ibm.com> wrote:
>
>> We now support CLEAR SUBCHANNEL and HALT SUBCHANNEL
>> via ccw_cmd_region.
>>
>
> Thanks, I forgot about this.
>
> Fixes: d5afd5d135c8 ("vfio-ccw: add handling for async channel instructions")
>

I don't know if this warranted a fixes tag but I will add it.

>> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
>> ---
>> Documentation/s390/vfio-ccw.rst | 31 ++++++++++++++++++++++++++++---
>> 1 file changed, 28 insertions(+), 3 deletions(-)
>>
>> diff --git a/Documentation/s390/vfio-ccw.rst b/Documentation/s390/vfio-ccw.rst
>> index 1f6d0b5..40e4110 100644
>> --- a/Documentation/s390/vfio-ccw.rst
>> +++ b/Documentation/s390/vfio-ccw.rst
>> @@ -180,6 +180,13 @@ The process of how these work together.
>> add it to an iommu_group and a vfio_group. Then we could pass through
>> the mdev to a guest.
>>
>> +
>> +VFIO-CCW Regions
>> +----------------
>> +
>> +The vfio-ccw driver exposes MMIO regions to accept requests from and return
>> +results to userspace.
>> +
>> vfio-ccw I/O region
>> -------------------
>>
>> @@ -205,6 +212,25 @@ irb_area stores the I/O result.
>>
>> ret_code stores a return code for each access of the region.
>>
>> +This region is always available.
>> +
>> +vfio-ccw cmd region
>> +-------------------
>> +
>> +The vfio-ccw cmd region is used to accept asynchronous instructions
>> +from userspace.
>> +
>> +#define VFIO_CCW_ASYNC_CMD_HSCH (1 << 0)
>> +#define VFIO_CCW_ASYNC_CMD_CSCH (1 << 1)
>> +struct ccw_cmd_region {
>> + __u32 command;
>> + __u32 ret_code;
>> +} __packed;
>> +
>> +This region is exposed via region type VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD.
>> +
>> +CLEAR SUBCHANNEL and HALT SUBCHANNEL currently uses this region.
>
> "Currently, CLEAR SUBCHANNEL and HALT SUBCHANNEL use this region". ?
>

This sounds better to me :)

>> +
>> vfio-ccw operation details
>> --------------------------
>>
>> @@ -306,9 +332,8 @@ Together with the corresponding work in QEMU, we can bring the passed
>> through DASD/ECKD device online in a guest now and use it as a block
>> device.
>>
>> -While the current code allows the guest to start channel programs via
>> -START SUBCHANNEL, support for HALT SUBCHANNEL or CLEAR SUBCHANNEL is
>> -not yet implemented.
>> +The current code allows the guest to start channel programs via
>> +START SUBCHANNEL, and supports HALT SUBCHANNEL or CLEAR SUBCHANNEL.
>
> "The current code allows the guest to start channel programs via START
> SUBCHANNEL, and to issue HALT SUBCHANNEL and CLEAR SUBCHANNEL." ?
>

Same. I will update with the changes you requested.

>>
>> vfio-ccw supports classic (command mode) channel I/O only. Transport
>> mode (HPF) is not supported.
>
>

Thanks for taking a look.

Thanks
Farhan