Re: [PATCH] kvm: emit GUEST_PANICKED event in case of abnormal KVM exit

[Andrey Drobyshev]

On 1/11/24 15:15, Andrey Drobyshev wrote:
> On 11/1/23 18:13, Denis V. Lunev wrote:
>> On 11/1/23 16:23, Andrey Drobyshev wrote:
>>> Currently we emit GUEST_PANICKED event in case kvm_vcpu_ioctl() returns
>>> KVM_EXIT_SYSTEM_EVENT with the event type KVM_SYSTEM_EVENT_CRASH.  Let's
>>> extend this scenario and emit GUEST_PANICKED in case of an abnormal KVM
>>> exit.  That's a natural thing to do since in this case guest is no
>>> longer operational anyway.
>>>
>>> Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
>>> Acked-by: Denis V. Lunev <den@virtuozzo.com>
>>> ---
>>>   accel/kvm/kvm-all.c | 19 +++++++++++++++----
>>>   1 file changed, 15 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
>>> index e39a810a4e..d74b3f0b0e 100644
>>> --- a/accel/kvm/kvm-all.c
>>> +++ b/accel/kvm/kvm-all.c
>>> @@ -2816,6 +2816,14 @@ static void kvm_eat_signals(CPUState *cpu)
>>>       } while (sigismember(&chkset, SIG_IPI));
>>>   }
>>>   +static void kvm_emit_guest_crash(CPUState *cpu)
>>> +{
>>> +    kvm_cpu_synchronize_state(cpu);
>>> +    qemu_mutex_lock_iothread();
>>> +    qemu_system_guest_panicked(cpu_get_crash_info(cpu));
>>> +    qemu_mutex_unlock_iothread();
>>> +}
>>> +
>>>   int kvm_cpu_exec(CPUState *cpu)
>>>   {
>>>       struct kvm_run *run = cpu->kvm_run;
>>> @@ -2969,21 +2977,24 @@ int kvm_cpu_exec(CPUState *cpu)
>>>                   ret = EXCP_INTERRUPT;
>>>                   break;
>>>               case KVM_SYSTEM_EVENT_CRASH:
>>> -                kvm_cpu_synchronize_state(cpu);
>>> -                qemu_mutex_lock_iothread();
>>> -                qemu_system_guest_panicked(cpu_get_crash_info(cpu));
>>> -                qemu_mutex_unlock_iothread();
>>> +                kvm_emit_guest_crash(cpu);
>>>                   ret = 0;
>>>                   break;
>>>               default:
>>>                   DPRINTF("kvm_arch_handle_exit\n");
>>>                   ret = kvm_arch_handle_exit(cpu, run);
>>> +                if (ret < 0) {
>>> +                    kvm_emit_guest_crash(cpu);
>>> +                }
>>>                   break;
>>>               }
>>>               break;
>>>           default:
>>>               DPRINTF("kvm_arch_handle_exit\n");
>>>               ret = kvm_arch_handle_exit(cpu, run);
>>> +            if (ret < 0) {
>>> +                kvm_emit_guest_crash(cpu);
>>> +            }
>>>               break;
>>>           }
>>>       } while (ret == 0);
>> This allows to gracefully handle this problem in production
>> and reset the guest using on_crash action in libvirt.
> 
> Ping

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