That's true, but extending fwcfg doesn't fit into the overall
picture well. We have well defined interfaces for pushing data into
a guest: virtio-serial (dma upload), virtio-blk (adds demand
paging), and virtio-p9fs (no image needed). Adapting libguestfs to
use one of these is a better move than adding yet another interface.
+1. I already proposed that. Nobody objects against fast fast
communication channel between guest and host. In fact we have one:
virtio-serial. Of course it is much easier to hack dma semantic into
fw_cfg interface than add virtio-serial to seabios, but it doesn't make
it right. Does virtio-serial has to be exposed as PCI to a guest or can
we expose it as ISA device too in case someone want to use -kernel option
but do not see additional PCI device in a guest?