On 09.04.2018 05:26, Stefan Hajnoczi wrote: > On Thu, Apr 05, 2018 at 08:09:26AM -0400, Pankaj Gupta wrote: >>> Will this raw file already have the "disk information header" (no idea >>> how that stuff is called) encoded? Are there any plans/possible ways to >>> >>> a) automatically create the headers? (if that's even possible) >> >> Its raw. Right now we are just supporting raw format. >> >> As this is direct mapping of memory into guest address space, I don't >> think we can have an abstraction of headers for block specific features. >> Or may be we can get opinion of others(Qemu block people) it is at all possible? > > memdev and the block layer are completely separate. The block layer > isn't designed for memory-mapped access. > Not questioning if this is the right thing to do now. I was wondering if we could expose any block device in the future as virtio-pmem. And I think with quite some work it could be possible. As you said, we will need some buffering. Maybe userfaultfd and friends (WP) could allow to implement that. > I think it makes sense to use memdev here. If the user wants a block > device, they should use an emulated block device, not virtio-pmem, > because buffering is necessary anyway when an image file format is used. > > Stefan > -- Thanks, David / dhildenb
