On Fri, May 21, 2021 at 12:38:20PM +0800, Chenyi Qiang wrote:
[...]
> @@ -4222,6 +4247,15 @@ void kvm_arch_pre_run(CPUState *cpu, struct kvm_run
> *run)
> }
> }
>
> +static void kvm_rate_limit_on_bus_lock(void)
> +{
> + uint64_t delay_ns = ratelimit_calculate_delay(&bus_lock_ratelimit_ctrl,
> 1);
> +
> + if (delay_ns) {
> + g_usleep(delay_ns / SCALE_US);
> + }
> +}
> +
> MemTxAttrs kvm_arch_post_run(CPUState *cpu, struct kvm_run *run)
> {
> X86CPU *x86_cpu = X86_CPU(cpu);
> @@ -4237,6 +4271,9 @@ MemTxAttrs kvm_arch_post_run(CPUState *cpu, struct
> kvm_run *run)
> } else {
> env->eflags &= ~IF_MASK;
> }
> + if (run->flags & KVM_RUN_X86_BUS_LOCK) {
Does the KVM API guarantee that KVM_RUN_X86_BUS_LOCK will never
be set if KVM_BUS_LOCK_DETECTION_EXIT isn't enabled? (Otherwise
we risk crashing in ratelimit_calculate_delay() above if rate
limiting is disabled).
If that's guaranteed, the patch looks good to me now.
> + kvm_rate_limit_on_bus_lock();
> + }
>
> /* We need to protect the apic state against concurrent accesses from
> * different threads in case the userspace irqchip is used. */
> @@ -4595,6 +4632,10 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run
> *run)
> ioapic_eoi_broadcast(run->eoi.vector);
> ret = 0;
> break;
> + case KVM_EXIT_X86_BUS_LOCK:
> + /* already handled in kvm_arch_post_run */
> + ret = 0;
> + break;
> default:
> fprintf(stderr, "KVM: unknown exit reason %d\n", run->exit_reason);
> ret = -1;
> --
> 2.17.1
>
--
Eduardo
