RE: [RFC v4 PATCH 00/49] Initial support of multi-process qemu - status update

[Thanos Makatos]

> > 3) Muser.ko pins the pages (in get_dma_map(), called from below)
> > (https://urldefense.proofpoint.com/v2/url?u=https-
> 3A__github.com_nutanix_muser_blob_master_kmod_muser.c-
> 23L711&d=DwICAg&c=s883GpUCOChKOHiocYtGcg&r=XTpYsh5Ps2zJvtw6ogtt
> i46atk736SI4vgsJiUKIyDE&m=C8rTp4SZoy4YNcZWntiROp3otxCyKbLoQXBw8O
> SB0TM&s=G2JfW1GcVNc_iph7C4hE285sTZM8JrR4dYXgmcyAZPE&e= )
> 
> Yikes, it pins every page??  vfio_pin_pages() intends for the vendor
> driver to be much smarter than this :-\  Thanks,

We no longer have to pin pages at all. Instead we grab the fd backing the VMA
and inject it in libmuser, and then request it to mmap that file. This also
solves a few other problems and is far simpler to implement.