[PATCH net-next 09/12] tools/virtio: switch to __ptr_ring_empty

[PATCH net-next 09/12] tools/virtio: switch to __ptr_ring_empty

[Michael S. Tsirkin]

We don't rely on lockless guarantees, but it
seems cleaner than inverting __ptr_ring_peek.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 tools/virtio/ringtest/ptr_ring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/virtio/ringtest/ptr_ring.c b/tools/virtio/ringtest/ptr_ring.c
index e6e8130..477899c 100644
--- a/tools/virtio/ringtest/ptr_ring.c
+++ b/tools/virtio/ringtest/ptr_ring.c
@@ -187,7 +187,7 @@ bool enable_kick()
 
 bool avail_empty()
 {
-	return !__ptr_ring_peek(&array);
+	return __ptr_ring_empty(&array);
 }
 
 bool use_buf(unsigned *lenp, void **bufp)
-- 
MST

[PATCH net-next 10/12] tools/virtio: more stubs to fix tools build

[Michael S. Tsirkin]

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 tools/virtio/linux/kernel.h      | 2 +-
 tools/virtio/linux/thread_info.h | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)
 create mode 100644 tools/virtio/linux/thread_info.h

diff --git a/tools/virtio/linux/kernel.h b/tools/virtio/linux/kernel.h
index 395521a..fca8381 100644
--- a/tools/virtio/linux/kernel.h
+++ b/tools/virtio/linux/kernel.h
@@ -118,7 +118,7 @@ static inline void free_page(unsigned long addr)
 #define dev_err(dev, format, ...) fprintf (stderr, format, ## __VA_ARGS__)
 #define dev_warn(dev, format, ...) fprintf (stderr, format, ## __VA_ARGS__)
 
-#define WARN_ON_ONCE(cond) ((cond) && fprintf (stderr, "WARNING\n"))
+#define WARN_ON_ONCE(cond) ((cond) ? fprintf (stderr, "WARNING\n") : 0)
 
 #define min(x, y) ({				\
 	typeof(x) _min1 = (x);			\
diff --git a/tools/virtio/linux/thread_info.h b/tools/virtio/linux/thread_info.h
new file mode 100644
index 0000000..e0f610d
--- /dev/null
+++ b/tools/virtio/linux/thread_info.h
@@ -0,0 +1 @@
+#define check_copy_size(A, B, C) (1)
-- 
MST

[PATCH net-next 11/12] tools/virtio: copy READ/WRITE_ONCE

[Michael S. Tsirkin]

This is to make ptr_ring test build again.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 tools/virtio/ringtest/main.h | 57 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/tools/virtio/ringtest/main.h b/tools/virtio/ringtest/main.h
index 5706e07..593a328 100644
--- a/tools/virtio/ringtest/main.h
+++ b/tools/virtio/ringtest/main.h
@@ -134,4 +134,61 @@ static inline void busy_wait(void)
     barrier(); \
 } while (0)
 
+#if defined(__i386__) || defined(__x86_64__) || defined(__s390x__)
+#define smp_wmb() barrier()
+#else
+#define smp_wmb() smp_release()
+#endif
+
+#ifdef __alpha__
+#define smp_read_barrier_depends() smp_acquire()
+#else
+#define smp_read_barrier_depends() do {} while(0)
+#endif
+
+static __always_inline
+void __read_once_size(const volatile void *p, void *res, int size)
+{
+        switch (size) {                                                 \
+        case 1: *(unsigned char *)res = *(volatile unsigned char *)p; break;              \
+        case 2: *(unsigned short *)res = *(volatile unsigned short *)p; break;            \
+        case 4: *(unsigned int *)res = *(volatile unsigned int *)p; break;            \
+        case 8: *(unsigned long long *)res = *(volatile unsigned long long *)p; break;            \
+        default:                                                        \
+                barrier();                                              \
+                __builtin_memcpy((void *)res, (const void *)p, size);   \
+                barrier();                                              \
+        }                                                               \
+}
+
+static __always_inline void __write_once_size(volatile void *p, void *res, int size)
+{
+	switch (size) {
+	case 1: *(volatile unsigned char *)p = *(unsigned char *)res; break;
+	case 2: *(volatile unsigned short *)p = *(unsigned short *)res; break;
+	case 4: *(volatile unsigned int *)p = *(unsigned int *)res; break;
+	case 8: *(volatile unsigned long long *)p = *(unsigned long long *)res; break;
+	default:
+		barrier();
+		__builtin_memcpy((void *)p, (const void *)res, size);
+		barrier();
+	}
+}
+
+#define READ_ONCE(x) \
+({									\
+	union { typeof(x) __val; char __c[1]; } __u;			\
+	__read_once_size(&(x), __u.__c, sizeof(x));		\
+	smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \
+	__u.__val;							\
+})
+
+#define WRITE_ONCE(x, val) \
+({							\
+	union { typeof(x) __val; char __c[1]; } __u =	\
+		{ .__val = (typeof(x)) (val) }; \
+	__write_once_size(&(x), __u.__c, sizeof(x));	\
+	__u.__val;					\
+})
+
 #endif
-- 
MST

[PATCH net-next 12/12] tools/virtio: fix smp_mb on x86

[Michael S. Tsirkin]

Offset 128 overlaps the last word of the redzone.
Use 132 which is always beyond that.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 tools/virtio/ringtest/main.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/virtio/ringtest/main.h b/tools/virtio/ringtest/main.h
index 593a328..301d59b 100644
--- a/tools/virtio/ringtest/main.h
+++ b/tools/virtio/ringtest/main.h
@@ -111,7 +111,7 @@ static inline void busy_wait(void)
 } 
 
 #if defined(__x86_64__) || defined(__i386__)
-#define smp_mb()     asm volatile("lock; addl $0,-128(%%rsp)" ::: "memory", "cc")
+#define smp_mb()     asm volatile("lock; addl $0,-132(%%rsp)" ::: "memory", "cc")
 #else
 /*
  * Not using __ATOMIC_SEQ_CST since gcc docs say they are only synchronized
-- 
MST

Re: [PATCH net-next 12/12] tools/virtio: fix smp_mb on x86

[Jason Wang]

On 2018年01月26日 07:36, Michael S. Tsirkin wrote:
> Offset 128 overlaps the last word of the redzone.
> Use 132 which is always beyond that.
>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>   tools/virtio/ringtest/main.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/virtio/ringtest/main.h b/tools/virtio/ringtest/main.h
> index 593a328..301d59b 100644
> --- a/tools/virtio/ringtest/main.h
> +++ b/tools/virtio/ringtest/main.h
> @@ -111,7 +111,7 @@ static inline void busy_wait(void)
>   }
>   
>   #if defined(__x86_64__) || defined(__i386__)
> -#define smp_mb()     asm volatile("lock; addl $0,-128(%%rsp)" ::: "memory", "cc")

Just wonder did "rsp" work for __i386__ ?

Thanks

> +#define smp_mb()     asm volatile("lock; addl $0,-132(%%rsp)" ::: "memory", "cc")
>   #else
>   /*
>    * Not using __ATOMIC_SEQ_CST since gcc docs say they are only synchronized

_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

Re: [PATCH net-next 12/12] tools/virtio: fix smp_mb on x86

[Michael S. Tsirkin]

On Fri, Jan 26, 2018 at 11:56:14AM +0800, Jason Wang wrote:
> 
> 
> On 2018年01月26日 07:36, Michael S. Tsirkin wrote:
> > Offset 128 overlaps the last word of the redzone.
> > Use 132 which is always beyond that.
> > 
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >   tools/virtio/ringtest/main.h | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/tools/virtio/ringtest/main.h b/tools/virtio/ringtest/main.h
> > index 593a328..301d59b 100644
> > --- a/tools/virtio/ringtest/main.h
> > +++ b/tools/virtio/ringtest/main.h
> > @@ -111,7 +111,7 @@ static inline void busy_wait(void)
> >   }
> >   #if defined(__x86_64__) || defined(__i386__)
> > -#define smp_mb()     asm volatile("lock; addl $0,-128(%%rsp)" ::: "memory", "cc")
> 
> Just wonder did "rsp" work for __i386__ ?
> 
> Thanks

Oh you are right of course. Probably no one ever run this one on i386 :)
I'll add a patch on top as this is not a new bug.

> > +#define smp_mb()     asm volatile("lock; addl $0,-132(%%rsp)" ::: "memory", "cc")
> >   #else
> >   /*
> >    * Not using __ATOMIC_SEQ_CST since gcc docs say they are only synchronized
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization