grant table API. Valid grant refs are in the range of positive 32bit
integers. ENOSPACE, being 29, is also a positive integer. Return
GNTTAB_LIST_END (-1) instead when gnttab_claim_grant_reference() fails.
Log:
- merge in latest xenbus from dfr's xenhvm
- fix race condition in xs_read_reply by converting tsleep to mtx_sleep
Log:
unmask evtchn in bind_{virq, ipi}_to_irq
Log:
- remove code for handling case of not being able to sleep
- eliminate tsleep - make sleeps atomic