On Sun, May 30, 2021 at 11:06:25AM -0400, Tianyu Lan wrote: > From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx> > > For Hyper-V isolation VM with AMD SEV SNP, the bounce buffer(shared memory) > needs to be accessed via extra address space(e.g address above bit39). > Hyper-V code may remap extra address space outside of swiotlb. swiotlb_ > bounce() needs to use remap virtual address to copy data from/to bounce > buffer. Add new interface swiotlb_set_bounce_remap() to do that. Why can't you use the bus_dma_region ranges to remap to your preferred address?