Re: [Qemu-devel] [RFC v2 04/34] cpu-exec: Migrate some generic fns to cpus.c

[Peter Crosthwaite]

On Mon, Jun 1, 2015 at 12:45 AM, Paolo Bonzini <address@hidden> wrote:
>
>
> On 31/05/2015 08:11, Peter Crosthwaite wrote:
>> The goal is to split the functions such that cpu-exec is CPU specific
>> content, while cpus.c is generic code only. The function interface to
>> cpu-exec needs to be virtualised to prepare support for multi-arch and
>> moving these definitions out saves bloating the QOM interface. So
>> move these definitions out of cpu-exec to the architecture independent
>> cpus.c.
>>
>> Signed-off-by: Peter Crosthwaite <address@hidden>
>> ---
>>  cpu-exec.c | 49 -------------------------------------------------
>>  cpus.c     | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 49 insertions(+), 49 deletions(-)
>>
>> diff --git a/cpu-exec.c b/cpu-exec.c
>> index 0266609..dbea47c 100644
>> --- a/cpu-exec.c
>> +++ b/cpu-exec.c
>> @@ -25,7 +25,6 @@
>>  #include "sysemu/qtest.h"
>>  #include "qemu/timer.h"
>>  #include "exec/address-spaces.h"
>> -#include "exec/memory-internal.h"
>>  #include "qemu/rcu.h"
>>
>>  /* -icount align implementation. */
>> @@ -127,52 +126,6 @@ static void init_delay_params(SyncClocks *sc, const 
>> CPUState *cpu)
>>  }
>>  #endif /* CONFIG USER ONLY */
>>
>> -void cpu_loop_exit(CPUState *cpu)
>> -{
>> -    cpu->current_tb = NULL;
>> -    siglongjmp(cpu->jmp_env, 1);
>> -}
>> -
>> -/* exit the current TB from a signal handler. The host registers are
>> -   restored in a state compatible with the CPU emulator
>> - */
>> -#if defined(CONFIG_SOFTMMU)
>> -void cpu_resume_from_signal(CPUState *cpu, void *puc)
>> -{
>> -    /* XXX: restore cpu registers saved in host registers */
>> -
>> -    cpu->exception_index = -1;
>> -    siglongjmp(cpu->jmp_env, 1);
>> -}
>> -
>> -void cpu_reload_memory_map(CPUState *cpu)
>
> This doesn't really belong in cpus.c...  I don't have a better
> suggestion though, so perhaps just add a FIXME in case one day there is
> a cpu-exec-common.c.
>

We need to go to the cpu-exec-common.c solution anyways due linux-user
usage of cpu_loop_exit(). cpus.c is compiled out for linux-user.

Regards,
Peter

> Paolo
>
>> -{
>> -    AddressSpaceDispatch *d;
>> -
>> -    if (qemu_in_vcpu_thread()) {
>> -        /* Do not let the guest prolong the critical section as much as it
>> -         * as it desires.
>> -         *
>> -         * Currently, this is prevented by the I/O thread's periodinc 
>> kicking
>> -         * of the VCPU thread (iothread_requesting_mutex, 
>> qemu_cpu_kick_thread)
>> -         * but this will go away once TCG's execution moves out of the 
>> global
>> -         * mutex.
>> -         *
>> -         * This pair matches cpu_exec's rcu_read_lock()/rcu_read_unlock(), 
>> which
>> -         * only protects cpu->as->dispatch.  Since we reload it below, we 
>> can
>> -         * split the critical section.
>> -         */
>> -        rcu_read_unlock();
>> -        rcu_read_lock();
>> -    }
>> -
>> -    /* The CPU and TLB are protected by the iothread lock.  */
>> -    d = atomic_rcu_read(&cpu->as->dispatch);
>> -    cpu->memory_dispatch = d;
>> -    tlb_flush(cpu, 1);
>> -}
>> -#endif
>> -
>>  /* Execute a TB, and fix up the CPU state afterwards if necessary */
>>  static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu, uint8_t *tb_ptr)
>>  {
>> @@ -344,8 +297,6 @@ static void cpu_handle_debug_exception(CPUState *cpu)
>>
>>  /* main execution loop */
>>
>> -volatile sig_atomic_t exit_request;
>> -
>>  int cpu_exec(CPUState *cpu)
>>  {
>>      CPUClass *cc = CPU_GET_CLASS(cpu);
>> diff --git a/cpus.c b/cpus.c
>> index c8a2911..2dc4a9a 100644
>> --- a/cpus.c
>> +++ b/cpus.c
>> @@ -28,6 +28,7 @@
>>  #include "monitor/monitor.h"
>>  #include "qapi/qmp/qerror.h"
>>  #include "sysemu/sysemu.h"
>> +#include "exec/memory-internal.h"
>>  #include "exec/gdbstub.h"
>>  #include "sysemu/dma.h"
>>  #include "sysemu/kvm.h"
>> @@ -64,6 +65,8 @@
>>
>>  #endif /* CONFIG_LINUX */
>>
>> +volatile sig_atomic_t exit_request;
>> +
>>  static CPUState *next_cpu;
>>  int64_t max_delay;
>>  int64_t max_advance;
>> @@ -1394,6 +1397,52 @@ static void tcg_exec_all(void)
>>      exit_request = 0;
>>  }
>>
>> +/* exit the current TB from a signal handler. The host registers are
>> +   restored in a state compatible with the CPU emulator
>> + */
>> +#if defined(CONFIG_SOFTMMU)
>> +void cpu_resume_from_signal(CPUState *cpu, void *puc)
>> +{
>> +    /* XXX: restore cpu registers saved in host registers */
>> +
>> +    cpu->exception_index = -1;
>> +    siglongjmp(cpu->jmp_env, 1);
>> +}
>> +
>> +void cpu_reload_memory_map(CPUState *cpu)
>> +{
>> +    AddressSpaceDispatch *d;
>> +
>> +    if (qemu_in_vcpu_thread()) {
>> +        /* Do not let the guest prolong the critical section as much as it
>> +         * as it desires.
>> +         *
>> +         * Currently, this is prevented by the I/O thread's periodinc 
>> kicking
>> +         * of the VCPU thread (iothread_requesting_mutex, 
>> qemu_cpu_kick_thread)
>> +         * but this will go away once TCG's execution moves out of the 
>> global
>> +         * mutex.
>> +         *
>> +         * This pair matches cpu_exec's rcu_read_lock()/rcu_read_unlock(), 
>> which
>> +         * only protects cpu->as->dispatch.  Since we reload it below, we 
>> can
>> +         * split the critical section.
>> +         */
>> +        rcu_read_unlock();
>> +        rcu_read_lock();
>> +    }
>> +
>> +    /* The CPU and TLB are protected by the iothread lock.  */
>> +    d = atomic_rcu_read(&cpu->as->dispatch);
>> +    cpu->memory_dispatch = d;
>> +    tlb_flush(cpu, 1);
>> +}
>> +#endif
>> +
>> +void cpu_loop_exit(CPUState *cpu)
>> +{
>> +    cpu->current_tb = NULL;
>> +    siglongjmp(cpu->jmp_env, 1);
>> +}
>> +
>>  void list_cpus(FILE *f, fprintf_function cpu_fprintf, const char *optarg)
>>  {
>>      /* XXX: implement xxx_cpu_list for targets that still miss it */
>>
>