Re: [Qemu-devel] [PATCH] introduce on_vcpu

[Glauber Costa <glommer@redhat.com>]

On Thu, Jul 16, 2009 at 04:19:54PM -0500, Anthony Liguori wrote:
> Glauber Costa wrote:
>> on_vcpu is a qemu-kvm function that will make sure that a specific
>> piece of code will run on a requested cpu. We don't need that because
>> we're restricted to -smp 1 right now, but those days are likely to end soon.
>>
>> So for the benefit of having qemu-kvm share more code with us, I'm
>> introducing our own version of on_vcpu(). Right now, we either run
>> a function on the current cpu, or abort the execution, because it would
>> mean something is seriously wrong.
>>
>> As an example code, I "ported" kvm_update_guest_debug to use it,
>> with some slight differences from qemu-kvm.
>>
>> This is probably 0.12 material
>>
>> Signed-off-by: Glauber Costa <glommer@redhat.com>
>> CC: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>  kvm-all.c |   37 +++++++++++++++++++++++++++++++------
>>  1 files changed, 31 insertions(+), 6 deletions(-)
>>
>> diff --git a/kvm-all.c b/kvm-all.c
>> index 4e913e5..1d91f2e 100644
>> --- a/kvm-all.c
>> +++ b/kvm-all.c
>> @@ -39,6 +39,8 @@
>>      do { } while (0)
>>  #endif
>>  +CPUState *current_env;
>> +
>>  typedef struct KVMSlot
>>  {
>>      target_phys_addr_t start_addr;
>> @@ -145,6 +147,14 @@ static int kvm_set_user_memory_region(KVMState *s, KVMSlot *slot)
>>      return kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
>>  }
>>  +static void on_vcpu(CPUState *env, void (*func)(void *data), void 
>> *data)
>> +{
>> +    if (env == current_env) {
>>   
>
> Can't you just use cpu_single_env?
Yes. Purpose of using curren_env was just to make it look more like qemu-kvm
But I do understand that we'll have to change it anyway for this code to
have any actual value, so I'm fine with using cpu_single_env.

>
>> +        func(data);
>> +        return;
>> +    }
>> +    assert(1);
>>   
>
> Wouldn't assert(env == current_env) or abort() make more sense?
abort() is fine. I can change it if you prefer.