On Tue, Aug 18, 2020 at 07:11:26PM -0300, Thiago Jung Bauermann wrote: > POWER secure guests (i.e., guests which use the Protection Execution > Facility) need to use SWIOTLB to be able to do I/O with the hypervisor, but > they don't need the SWIOTLB memory to be in low addresses since the > hypervisor doesn't have any addressing limitation. > > This solves a SWIOTLB initialization problem we are seeing in secure guests > with 128 GB of RAM: they are configured with 4 GB of crashkernel reserved > memory, which leaves no space for SWIOTLB in low addresses. > > To do this, we use mostly the same code as swiotlb_init(), but allocate the > buffer using memblock_alloc() instead of memblock_alloc_low(). > > Signed-off-by: Thiago Jung Bauermann <bauer...@linux.ibm.com>
Looks fine to me (except for the pointlessly long comment lines, but I've been told that's the powerpc way).
