[PATCH v5 12/18] xen/pvcalls: implement poll command

Implement poll on passive sockets by requesting a delayed response with mappass->reqcopy, and reply back when there is data on the passive socket. Poll on active socket is unimplemented as by the spec, as the frontend should just wait for events and check the indexes on the indexes page. Only

[PATCH v5 12/18] xen/pvcalls: implement poll command

Implement poll on passive sockets by requesting a delayed response with mappass->reqcopy, and reply back when there is data on the passive socket. Poll on active socket is unimplemented as by the spec, as the frontend should just wait for events and check the indexes on the indexes page. Only