User space may only inject interrupts during kvm_arch_pre_run if
ready_for_interrupt_injection is set in kvm_run. But that field is
updated on exit from KVM_RUN, so we must ensure that we enter the
kernel after potentially queuing an interrupt, otherwise we risk to
loose one - like it happens with the current code against latest
kernel modules (since kvm-86) that started to queue only a single
interrupt.
Fix the problem by reordering kvm_cpu_exec.
Credits go to Gleb Natapov for analyzing the issue in details.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
dprintf("kvm_cpu_exec()\n");
do {
- kvm_arch_pre_run(env, run);
-
if (env->exit_request) {
dprintf("interrupt exit requested\n");
ret = 0;
break;
}
+ kvm_arch_pre_run(env, run);
ret = kvm_vcpu_ioctl(env, KVM_RUN, 0);
kvm_arch_post_run(env, run);