Adding and Removing Buffers While Event Logging is Active

The guest can call the HvCreateEventLogBuffer hypercall function to add new buffers to the event log buffer group at any time. New buffers enter the internal "standby" state until they are mapped through a call to the HvMapEventLogBuffer hypercall function, at which time they enter service as an available free buffer.

The guest can likewise remove buffers from the event log buffer group, but must do so in a special sequence. Removing a buffer begins by unmapping it through a call to the HvUnmapEventLogBuffer hypercall function. Unmapping returns a buffer to the internal "standby" state thereby taking the buffer out of service. The buffer can only be unmapped when it is either in the "free" or "ready" state (a flush operation can be used to bring "in use" buffers to the "completed" state and, subsequently, all "completed" buffers to the "ready" state). An unmapped buffer can be deleted at any time through a call to HvDeleteEventLogBuffer hypercall function.

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Build date: 11/16/2013