To fully support interrupt mode for the vfio-user transport, we need to
arrange to wake up in one of two conditions:
- we receive a vfio-user message on the socket
- a client writes to one of our BARs
In response, we can process any pending vfio-user messages, as well as
poll the actual queue pairs.
As there is no way for a client-mapped BAR write to cause us to wake up,
interrupt mode can only work when mappable BAR0 is disabled. In that
case, each BAR write becomes a vfio-user message, and can thus be
handled by registering the libvfio-user socket fd with SPDK.
For the poll group poller, we enable interrupt mode for it during the
vfio-user ->poll_group_create() callback; this only works in the case
that no other transports without interrupt mode support are sharing that
poll group.
Signed-off-by: John Levon <john.levon@nutanix.com>
Change-Id: Ic784d01078b2006edb27892fc0613f934eca930b
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/10722
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Community-CI: Mellanox Build Bot
2089c410ca