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

[Andrey Drobyshev]

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.

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