On Sun, Mar 12, 2017 at 2:34 PM, Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx> wrote: > 2017-03-09 18:38 GMT+01:00 Laura Abbott <labbott@xxxxxxxxxx>: >> On 03/09/2017 02:00 AM, Benjamin Gaignard wrote: >>> 2017-03-06 17:04 GMT+01:00 Daniel Vetter <daniel@xxxxxxxx>: >>>> On Mon, Mar 06, 2017 at 11:58:05AM +0100, Mark Brown wrote: >>>>> On Mon, Mar 06, 2017 at 11:40:41AM +0100, Daniel Vetter wrote: >>>>> >>>>>> No one gave a thing about android in upstream, so Greg KH just dumped it >>>>>> all into staging/android/. We've discussed ION a bunch of times, recorded >>>>>> anything we'd like to fix in staging/android/TODO, and Laura's patch >>>>>> series here addresses a big chunk of that. >>>>> >>>>>> This is pretty much the same approach we (gpu folks) used to de-stage the >>>>>> syncpt stuff. >>>>> >>>>> Well, there's also the fact that quite a few people have issues with the >>>>> design (like Laurent). It seems like a lot of them have either got more >>>>> comfortable with it over time, or at least not managed to come up with >>>>> any better ideas in the meantime. >>>> >>>> See the TODO, it has everything a really big group (look at the patch for >>>> the full Cc: list) figured needs to be improved at LPC 2015. We don't just >>>> merge stuff because merging stuff is fun :-) >>>> >>>> Laurent was even in that group ... >>>> -Daniel >>> >>> For me those patches are going in the right direction. >>> >>> I still have few questions: >>> - since alignment management has been remove from ion-core, should it >>> be also removed from ioctl structure ? >> >> Yes, I think I'm going to go with the suggestion to fixup the ABI >> so we don't need the compat layer and as part of that I'm also >> dropping the align argument. >> >>> - can you we ride off ion_handle (at least in userland) and only >>> export a dma-buf descriptor ? >> >> Yes, I think this is the right direction given we're breaking >> everything anyway. I was debating trying to keep the two but >> moving to only dma bufs is probably cleaner. The only reason >> I could see for keeping the handles is running out of file >> descriptors for dma-bufs but that seems unlikely. >>> >>> In the future how can we add new heaps ? >>> Some platforms have very specific memory allocation >>> requirements (just have a look in the number of gem custom allocator in drm) >>> Do you plan to add heap type/mask for each ? >> >> Yes, that was my thinking. > > My concern is about the policy to adding heaps, will you accept > "customs" heap per > platforms ? per devices ? or only generic ones ? > If you are too strict, we will have lot of out-of-tree heaps and if > you accept of of them > it will be a nightmare to maintain.... I think ion should expose any heap that's also directly accessible to devices using dma_alloc(_coherent). That should leave very few things left, like your SMA heap. > Another point is how can we put secure rules (like selinux policy) on > heaps since all the allocations > go to the same device (/dev/ion) ? For example, until now, in Android > we have to give the same > access rights to all the process that use ION. > It will become problem when we will add secure heaps because we won't > be able to distinguish secure > processes to standard ones or set specific policy per heaps. > Maybe I'm wrong here but I have never see selinux policy checking an > ioctl field but if that > exist it could be a solution. Hm, we might want to expose all the heaps as individual /dev/ion_$heapname nodes? Should we do this from the start, since we're massively revamping the uapi anyway (imo not needed, current state seems to work too)? -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
