On 23/09/19 11:31, Vitaly Kuznetsov wrote: > +#ifdef CONFIG_RETPOLINE > + if (exit_reason == EXIT_REASON_MSR_WRITE) > + return handle_wrmsr(vcpu); > + else if (exit_reason == EXIT_REASON_PREEMPTION_TIMER) > + return handle_preemption_timer(vcpu); > + else if (exit_reason == EXIT_REASON_PENDING_INTERRUPT) > + return handle_interrupt_window(vcpu); > + else if (exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT) > + return handle_external_interrupt(vcpu); > + else if (exit_reason == EXIT_REASON_HLT) > + return handle_halt(vcpu); > + else if (exit_reason == EXIT_REASON_PAUSE_INSTRUCTION) > + return handle_pause(vcpu); > + else if (exit_reason == EXIT_REASON_MSR_READ) > + return handle_rdmsr(vcpu); > + else if (exit_reason == EXIT_REASON_CPUID) > + return handle_cpuid(vcpu); > + else if (exit_reason == EXIT_REASON_EPT_MISCONFIG) > + return handle_ept_misconfig(vcpu); > +#endif > return kvm_vmx_exit_handlers[exit_reason](vcpu); Most of these, while frequent, are already part of slow paths. I would keep only EXIT_REASON_MSR_WRITE, EXIT_REASON_PREEMPTION_TIMER, EXIT_REASON_EPT_MISCONFIG and add EXIT_REASON_IO_INSTRUCTION. If you make kvm_vmx_exit_handlers const, can the compiler substitute for instance kvm_vmx_exit_handlers[EXIT_REASON_MSR_WRITE] with handle_wrmsr? Just thinking out loud, not sure if it's an improvement code-wise. Paolo Paolo
