Hi everyone,
commit 6ae2df93c277b4093b3e54c9606387
d1ba6d10fe
into xen-staging includes a new function in xenctrl.h,
xc_mem_event_enable. This function name however has been used previously
in xenctrl.h up till at least Xen 4.1.2 for a different purpose. We
have been using autoconf to check which version of the mem_access API is
available in Xen by checking if xc_mem_event_enable is available,
signaling that the mem_access API is Xen 4.1 style, and for
xc_mem_access_enable signaling 4.2+ style API. See
https://github.com/bdpayne/libvmi/blob/master/configure.ac#L140 for more details.
Now with this function being reintroduced, it becomes more
complicated to determine which version of the mem_access API does Xen
actually provide. A #define indicating mem_access API version would
nicely overcome this issue, or naming xc_mem_event_enable
something else.
Furthermore, the new xc_mem_event_enable function unconditionally unpauses the VM. This may not be a desired behavior in all cases, especially if the VM was in a paused state when the function was called.