Nicholas Piggin [npig...@gmail.com] wrote: > On Mon, 14 Aug 2017 15:21:48 +1000 > Michael Ellerman <m...@ellerman.id.au> wrote: > > > Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com> writes: > > > > arch/powerpc/include/asm/vas.h | 35 ++++ > > > arch/powerpc/include/uapi/asm/vas.h | 25 +++ > > > > I thought we weren't exposing VAS to userspace yet? > > > > If we are then we need to get things straight WRT copy/paste abort. >
> No we should not be. This might be just a leftover hunk that should > be moved to a future series. Yes, I should have posted patches 14..17 separately as an RFC that goes on top of the VAS kernel patches 1..13. > > At the moment (as far as I understand) it should be limited to > preempt-disabled, process context, kernel users which avoids any > concern for switch_to. > In the FTW case, there is no data transfer from user space to the hardware. i.e the copy/paste submit a NULL CRB and hardware will be configured (see ->fifo_disable setting in winctx) to ignore any data they specify in the CRB. Would we be able to allow copy/paste from user space in that case? Sukadev