Minimizing VMExits in Private Cloud by Aggressive PV IPI and Passthrough Timer
summary
Implements a passthrough timer so guests program the physical LAPIC and the host swaps host LAPIC/TSC state on entry/exit, disables TSC MSR intercept, and adjusts TSC; this removes timer-related VMExits and raises memcached set/get throughput by about +35.5%. Implements a low-exit PV IPI path using a guest pv_desc posted-interrupt bitmap and direct post interrupts so multi-CPU IPIs merge without hypercall exits, dropping single IPI cost from ~11,486 cycles to ~412 and improving memcached by +14.8%. Requires trusted guests.
AI-written summary · about