On Wed, 15 May 2019 09:36:01 -0400 Eric Farman <farman@xxxxxxxxxxxxx> wrote: > On 5/15/19 8:43 AM, Cornelia Huck wrote: > > On Wed, 15 May 2019 01:42:48 +0200 > > Eric Farman <farman@xxxxxxxxxxxxx> wrote: > > > >> If the CCW being processed is a No-Operation, then by definition no > >> data is being transferred. Let's fold those checks into the normal > >> CCW processors, rather than skipping out early. > >> > >> Likewise, if the CCW being processed is a "test" (an invented > >> definition to simply mean it ends in a zero), let's permit that to go > >> through to the hardware. There's nothing inherently unique about > >> those command codes versus one that ends in an eight [1], or any other > >> otherwise valid command codes that are undefined for the device type > >> in question. > > > > Hm... let's tweak that a bit? It's not that "test" is an invented > > category; it's just that this has not been a valid command for > > post-s/370 and therefore should not get any special treatment and just > > be sent to the hardware? > > Agreed, I should've re-read that one before I sent it... How about: > > Likewise, if the CCW being processed is a "test" (a category defined > here as an opcode that contains zero in the lowest four bits) then no > special processing is necessary as far as vfio-ccw is concerned. > These command codes have not been valid since the S/370 days, meaning > they are invalid in the same way as one that ends in an eight [1] or > an otherwise valid command code that is undefined for the device type > in question. Considering that, let's just process "test" CCWs like > any other CCW, and send everything to the hardware. Sounds good to me! > > > > >> > >> [1] POPS states that a x08 is a TIC CCW, and that having any high-order > >> bits enabled is invalid for format-1 CCWs. For format-0 CCWs, the > >> high-order bits are ignored. > >> > >> Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx> > >> --- > >> drivers/s390/cio/vfio_ccw_cp.c | 11 +++++------ > >> 1 file changed, 5 insertions(+), 6 deletions(-) > > >
