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

[Frederic Konrad]

On 26/06/2015 16:55, Paolo Bonzini wrote:
> On 26/06/2015 16:47, address@hidden wrote:
> > From: Guillaume Delbergue <address@hidden>
> >
> > 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 <address@hidden>
> > ---
> >   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));