Re: [Qemu-devel] [PATCH v2 6/8] cpu: make CPU_INTERRUPT_RESET available on all targets

[Paolo Bonzini <pbonzini@redhat.com>]

Il 23/05/2014 19:59, Peter Maydell ha scritto:
> On 2 May 2014 15:33, Paolo Bonzini <pbonzini@redhat.com> wrote:
>> On the x86, some devices need access to the CPU reset pin (INIT#).
>> Provide a generic service to do this, using one of the internal
>> cpu_interrupt targets.  Generalize the PPC-specific code for
>> CPU_INTERRUPT_RESET to other targets.
>>
>> Since PPC does not support migration across QEMU versions (its
>> machine types are not versioned yet), I picked the value that
>> is used on x86, CPU_INTERRUPT_TGT_INT_1.  Consequently, TGT_INT_2
>> and TGT_INT_3 are shifted down by one while keeping their value.
>>
>> Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>>  cpu-exec.c             | 23 +++++++++++++----------
>>  cpus.c                 |  9 +++++++++
>>  include/exec/cpu-all.h |  8 +++++---
>>  include/sysemu/cpus.h  |  1 +
>>  target-i386/cpu.h      |  7 ++++---
>>  target-ppc/cpu.h       |  3 ---
>>  6 files changed, 32 insertions(+), 19 deletions(-)
>>
>> diff --git a/cpu-exec.c b/cpu-exec.c
>> index 2f54054..38e5f02 100644
>> --- a/cpu-exec.c
>> +++ b/cpu-exec.c
>> @@ -336,19 +336,25 @@ int cpu_exec(CPUArchState *env)
>>                      }
>>  #endif
>>  #if defined(TARGET_I386)
>> +                    if (interrupt_request & CPU_INTERRUPT_INIT) {
>> +                        cpu_svm_check_intercept_param(env, SVM_EXIT_INIT, 0);
>> +                        do_cpu_init(x86_cpu);
>> +                        cpu->exception_index = EXCP_HALTED;
>> +                        cpu_loop_exit(cpu);
>> +                    }
>> +#else
>> +                    if (interrupt_request & CPU_INTERRUPT_RESET) {
>> +                        cpu_reset(cpu);
>> +                    }
>> +#endif
>
> I was looking at cleaning up the horrible ifdef ladder a little
> lower in this function, and I noticed this code had been
> added recently. Why is TARGET_I386 a special case here?

Because a hypervisor (cpu_svm_check_intercept_param) can block the 
interrupt.  Note that CPU_INTERRUPT_INIT is actually the same bit as 
CPU_INTERRUPT_RESET.

The whole #ifdef mess should probably be changed to a function in cpu.c, 
now that we don't have AREG0 constraints anymore.

Paolo