Re: [PATCH v3 2/3] KVM: keep track of running ioctls

[Emanuele Giuseppe Esposito]

Am 17/11/2022 um 20:27 schrieb David Hildenbrand:
> On 11.11.22 16:47, Emanuele Giuseppe Esposito wrote:
>> Using the new accel-blocker API, mark where ioctls are being called
>> in KVM. Next, we will implement the critical section that will take
>> care of performing memslots modifications atomically, therefore
>> preventing any new ioctl from running and allowing the running ones
>> to finish.
>>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
> 
> You might want to drop that and instead mention something like "This
> patch is based on a protoype patch by David Hildenbrand".
> 
>> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
>> ---
>>   accel/kvm/kvm-all.c | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
>> index f99b0becd8..ff660fd469 100644
>> --- a/accel/kvm/kvm-all.c
>> +++ b/accel/kvm/kvm-all.c
>> @@ -2310,6 +2310,7 @@ static int kvm_init(MachineState *ms)
>>       assert(TARGET_PAGE_SIZE <= qemu_real_host_page_size());
>>         s->sigmask_len = 8;
>> +    accel_blocker_init();
>>     #ifdef KVM_CAP_SET_GUEST_DEBUG
>>       QTAILQ_INIT(&s->kvm_sw_breakpoints);
>> @@ -3014,7 +3015,9 @@ int kvm_vm_ioctl(KVMState *s, int type, ...)
>>       va_end(ap);
>>         trace_kvm_vm_ioctl(type, arg);
>> +    accel_ioctl_begin();
>>       ret = ioctl(s->vmfd, type, arg);
>> +    accel_ioctl_end();
>>       if (ret == -1) {
>>           ret = -errno;
>>       }
>> @@ -3032,7 +3035,9 @@ int kvm_vcpu_ioctl(CPUState *cpu, int type, ...)
>>       va_end(ap);
>>         trace_kvm_vcpu_ioctl(cpu->cpu_index, type, arg);
>> +    accel_cpu_ioctl_begin(cpu);
>>       ret = ioctl(cpu->kvm_fd, type, arg);
>> +    accel_cpu_ioctl_end(cpu);
>>       if (ret == -1) {
>>           ret = -errno;
>>       }
>> @@ -3050,7 +3055,9 @@ int kvm_device_ioctl(int fd, int type, ...)
>>       va_end(ap);
>>         trace_kvm_device_ioctl(fd, type, arg);
>> +    accel_ioctl_begin();
>>       ret = ioctl(fd, type, arg);
>> +    accel_ioctl_end();
>>       if (ret == -1) {
>>           ret = -errno;
>>       }
> 
> I recall that I had some additional patches that tried to catch some of
> more calls:
> 
> https://lore.kernel.org/qemu-devel/20200312161217.3590-2-david@redhat.com/
> 
> https://lore.kernel.org/qemu-devel/20200312161217.3590-3-david@redhat.com/
> 
> Do they still apply? Is there more?
> 

Apologies, what do you mean with "do they still apply"?
Looks fine to me

Emanuele