Hi Jean-Philippe, On Thu, Dec 13, 2018 at 12:50:29PM +0000, Jean-Philippe Brucker wrote: > We already do deferred flush: UNMAP requests are added to the queue by > iommu_unmap(), and then flushed out by iotlb_sync(). So we switch to the > host only on iotlb_sync(), or when the request queue is full. So the mappings can stay in place until iotlb_sync() returns? What happens when the guest sends a map-request for a region it sent and unmap request before, but did not call iotlb_sync inbetween? Regards, Joerg
