On Wed, Apr 27, 2022 at 11:34:20AM -0400, Tamas K Lengyel wrote: > Add monitor event that hooks the vmexit handler allowing for both sync and > async monitoring of events. With async monitoring an event is placed on the > monitor ring for each exit and the rest of the vmexit handler resumes > normally. > If there are additional monitor events configured those will also place their > respective events on the monitor ring. > > With the sync version an event is placed on the monitor ring but the handler > does not get resumed, thus the sync version is only useful when the VM is not > expected to resume normally after the vmexit. Our use-case is primarily with > the sync version with VM forks where the fork gets reset after sync vmexit > event, thus the rest of the vmexit handler can be safely skipped. This is > very useful when we want to avoid Xen crashing the VM under any circumstance, > for example during fuzzing. Collecting all vmexit information regardless of > the root cause makes it easier to reason about the state of the VM on the > monitor side, hence we opt to receive all events, even for external interrupt > and NMI exits and let the monitor agent decide how to proceed. > > Signed-off-by: Tamas K Lengyel <tamas.leng...@intel.com>
Reviewed-by: Roger Pau Monné <roger....@citrix.com> Thanks, Roger.
