On Fri, Jun 28, 2019 at 01:59:26PM +0100, Burakov, Anatoly wrote: > On 28-Jun-19 1:46 PM, Bruce Richardson wrote: > > On Thu, Jun 27, 2019 at 01:28:04PM +0100, Burakov, Anatoly wrote: > > > On 27-Jun-19 11:40 AM, Bruce Richardson wrote: > > > > Add the create/destroy driver functions so that we can actually allocate > > > > a rawdev and destroy it when done. No rawdev API functions are actually > > > > implemented at this point. > > > > > > > > Signed-off-by: Bruce Richardson <bruce.richard...@intel.com> > > > > --- > > > > > > <snip> > > > > > > > + rawdev->driver_name = dev->device.driver->name; > > > > + > > > > + ioat = rawdev->dev_private; > > > > + ioat->rawdev = rawdev; > > > > + ioat->regs = dev->mem_resource[0].addr; > > > > + ioat->ring_size = 0; > > > > + ioat->desc_ring = NULL; > > > > + ioat->status_addr = rte_malloc_virt2iova(ioat) + > > > > + offsetof(struct rte_ioat_rawdev, status); > > > > > > While reviewing other patch, i remembered that i've seen this here. You > > > can't make any guarantees about IOVA addresses in rte_malloc-allocated > > > memory. Are you sure you don't require IOVA-contiguous memory here? > > > > > Presumably we can guarantee that for structures less than 1 page in size, > > this will work? I believe the device structure should be within that page > > limit. > > > > No, we can't. That would only be true if you were allocating IOVA-contiguous > memory. Otherwise there's nothing stopping the allocator to allocate even a > few kilobytes across page boundary. > > You can only ever guarantee that *one cache line* will not cross the page > boundary with rte_malloc. With rte_memzone and IOVA_CONTIG flag, you'll be > able to guarantee IOVA-contiguousness in all cases (or allocation failure). > Ok, so I either need to move this field to the start of the structure, i.e. have offset zero, or else use contiguous allocation. Will fix in next version.
/Bruce
