diff options
| -rw-r--r-- | hw/virtio.c | 14 |
1 files changed, 3 insertions, 11 deletions
diff --git a/hw/virtio.c b/hw/virtio.c index d9bf266492..7011b5b398 100644 --- a/hw/virtio.c +++ b/hw/virtio.c @@ -16,20 +16,12 @@ #include "trace.h" #include "qemu-error.h" #include "virtio.h" +#include "qemu-barrier.h" /* The alignment to use between consumer and producer parts of vring. * x86 pagesize again. */ #define VIRTIO_PCI_VRING_ALIGN 4096 -/* QEMU doesn't strictly need write barriers since everything runs in - * lock-step. We'll leave the calls to wmb() in though to make it obvious for - * KVM or if kqemu gets SMP support. - * In any case, we must prevent the compiler from reordering the code. - * TODO: we likely need some rmb()/mb() as well. - */ - -#define wmb() __asm__ __volatile__("": : :"memory") - typedef struct VRingDesc { uint64_t addr; @@ -264,7 +256,7 @@ void virtqueue_flush(VirtQueue *vq, unsigned int count) { uint16_t old, new; /* Make sure buffer is written before we update index. */ - wmb(); + smp_wmb(); trace_virtqueue_flush(vq, count); old = vring_used_idx(vq); new = old + count; @@ -324,7 +316,7 @@ static unsigned virtqueue_next_desc(target_phys_addr_t desc_pa, /* Check they're not leading us off end of descriptors. */ next = vring_desc_next(desc_pa, i); /* Make sure compiler knows to grab that: we don't want it changing! */ - wmb(); + smp_wmb(); if (next >= max) { error_report("Desc next is %u", next); |