Re: [Qemu-devel] [RFC PATCH V6 04/18] add support for spin lock on POSIX systems exclusively

[Frederic Konrad <fred.konrad@greensocs.com>]

On 26/06/2015 16:55, Paolo Bonzini wrote:
>
> On 26/06/2015 16:47, fred.konrad@greensocs.com wrote:
>> From: Guillaume Delbergue <guillaume.delbergue@greensocs.com>
>>
>> WARNING: spin lock is currently not implemented on WIN32
> The Windows KSPIN_LOCK is a kernel data structure.  You can implement a
> simple, portable test-and-test-and-set spinlock using atomics, and use
> it on both POSIX and Win32.
>
> Paolo

ok we will take a look at atomic instruction.

Fred
>
>> Signed-off-by: Guillaume Delbergue <guillaume.delbergue@greensocs.com>
>> ---
>>   include/qemu/thread-posix.h |  4 ++++
>>   include/qemu/thread-win32.h |  4 ++++
>>   include/qemu/thread.h       |  7 +++++++
>>   util/qemu-thread-posix.c    | 45 +++++++++++++++++++++++++++++++++++++++++++++
>>   util/qemu-thread-win32.c    | 30 ++++++++++++++++++++++++++++++
>>   5 files changed, 90 insertions(+)
>>
>> diff --git a/include/qemu/thread-posix.h b/include/qemu/thread-posix.h
>> index eb5c7a1..8ce8f01 100644
>> --- a/include/qemu/thread-posix.h
>> +++ b/include/qemu/thread-posix.h
>> @@ -7,6 +7,10 @@ struct QemuMutex {
>>       pthread_mutex_t lock;
>>   };
>>   
>> +struct QemuSpin {
>> +    pthread_spinlock_t lock;
>> +};
>> +
>>   struct QemuCond {
>>       pthread_cond_t cond;
>>   };
>> diff --git a/include/qemu/thread-win32.h b/include/qemu/thread-win32.h
>> index 3d58081..310c8bd 100644
>> --- a/include/qemu/thread-win32.h
>> +++ b/include/qemu/thread-win32.h
>> @@ -7,6 +7,10 @@ struct QemuMutex {
>>       LONG owner;
>>   };
>>   
>> +struct QemuSpin {
>> +    PKSPIN_LOCK lock;
>> +};
>> +
>>   struct QemuCond {
>>       LONG waiters, target;
>>       HANDLE sema;
>> diff --git a/include/qemu/thread.h b/include/qemu/thread.h
>> index 5114ec8..f5d1259 100644
>> --- a/include/qemu/thread.h
>> +++ b/include/qemu/thread.h
>> @@ -5,6 +5,7 @@
>>   #include <stdbool.h>
>>   
>>   typedef struct QemuMutex QemuMutex;
>> +typedef struct QemuSpin QemuSpin;
>>   typedef struct QemuCond QemuCond;
>>   typedef struct QemuSemaphore QemuSemaphore;
>>   typedef struct QemuEvent QemuEvent;
>> @@ -25,6 +26,12 @@ void qemu_mutex_lock(QemuMutex *mutex);
>>   int qemu_mutex_trylock(QemuMutex *mutex);
>>   void qemu_mutex_unlock(QemuMutex *mutex);
>>   
>> +void qemu_spin_init(QemuSpin *spin);
>> +void qemu_spin_destroy(QemuSpin *spin);
>> +void qemu_spin_lock(QemuSpin *spin);
>> +int qemu_spin_trylock(QemuSpin *spin);
>> +void qemu_spin_unlock(QemuSpin *spin);
>> +
>>   void qemu_cond_init(QemuCond *cond);
>>   void qemu_cond_destroy(QemuCond *cond);
>>   
>> diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c
>> index ba67cec..224bacc 100644
>> --- a/util/qemu-thread-posix.c
>> +++ b/util/qemu-thread-posix.c
>> @@ -89,6 +89,51 @@ void qemu_mutex_unlock(QemuMutex *mutex)
>>           error_exit(err, __func__);
>>   }
>>   
>> +void qemu_spin_init(QemuSpin *spin)
>> +{
>> +    int err;
>> +
>> +    err = pthread_spin_init(&spin->lock, 0);
>> +    if (err) {
>> +        error_exit(err, __func__);
>> +    }
>> +}
>> +
>> +void qemu_spin_destroy(QemuSpin *spin)
>> +{
>> +    int err;
>> +
>> +    err = pthread_spin_destroy(&spin->lock);
>> +    if (err) {
>> +        error_exit(err, __func__);
>> +    }
>> +}
>> +
>> +void qemu_spin_lock(QemuSpin *spin)
>> +{
>> +    int err;
>> +
>> +    err = pthread_spin_lock(&spin->lock);
>> +    if (err) {
>> +        error_exit(err, __func__);
>> +    }
>> +}
>> +
>> +int qemu_spin_trylock(QemuSpin *spin)
>> +{
>> +    return pthread_spin_trylock(&spin->lock);
>> +}
>> +
>> +void qemu_spin_unlock(QemuSpin *spin)
>> +{
>> +    int err;
>> +
>> +    err = pthread_spin_unlock(&spin->lock);
>> +    if (err) {
>> +        error_exit(err, __func__);
>> +    }
>> +}
>> +
>>   void qemu_cond_init(QemuCond *cond)
>>   {
>>       int err;
>> diff --git a/util/qemu-thread-win32.c b/util/qemu-thread-win32.c
>> index 406b52f..6fbe6a8 100644
>> --- a/util/qemu-thread-win32.c
>> +++ b/util/qemu-thread-win32.c
>> @@ -80,6 +80,36 @@ void qemu_mutex_unlock(QemuMutex *mutex)
>>       LeaveCriticalSection(&mutex->lock);
>>   }
>>   
>> +void qemu_spin_init(QemuSpin *spin)
>> +{
>> +    printf("spinlock not implemented");
>> +    abort();
>> +}
>> +
>> +void qemu_spin_destroy(QemuSpin *spin)
>> +{
>> +    printf("spinlock not implemented");
>> +    abort();
>> +}
>> +
>> +void qemu_spin_lock(QemuSpin *spin)
>> +{
>> +    printf("spinlock not implemented");
>> +    abort();
>> +}
>> +
>> +int qemu_spin_trylock(QemuSpin *spin)
>> +{
>> +    printf("spinlock not implemented");
>> +    abort();
>> +}
>> +
>> +void qemu_spin_unlock(QemuSpin *spin)
>> +{
>> +    printf("spinlock not implemented");
>> +    abort();
>> +}
>> +
>>   void qemu_cond_init(QemuCond *cond)
>>   {
>>       memset(cond, 0, sizeof(*cond));
>>