On Wed, Jul 28, 2021 at 10:52:28AM -0400, Tianyu Lan wrote: > In Isolation VM, all shared memory with host needs to mark visible > to host via hvcall. vmbus_establish_gpadl() has already done it for > storvsc rx/tx ring buffer. The page buffer used by vmbus_sendpacket_ > mpb_desc() still need to handle. Use DMA API to map/umap these > memory during sending/receiving packet and Hyper-V DMA ops callback > will use swiotlb function to allocate bounce buffer and copy data > from/to bounce buffer. I am wondering why you dont't use DMA-API unconditionally? It provides enough abstraction to do the right thing for isolated and legacy VMs. Regards, Joerg