On Mon, Feb 01, 2016 at 10:00:56AM -0800, Andy Lutomirski wrote: > This leaves vring_new_virtqueue alone for compatbility, but it > adds two new improved APIs: > > vring_create_virtqueue: Creates a virtqueue backed by automatically > allocated coherent memory. (Some day it this could be extended to > support non-coherent memory, too, if there ends up being a platform > on which it's worthwhile.) > > __vring_new_virtqueue: Creates a virtqueue with a manually-specified > layout. This should allow mic_virtio to work much more cleanly. > > Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> > --- > drivers/virtio/virtio_ring.c | 178 +++++++++++++++++++++++++++++++++++-------- > include/linux/virtio.h | 23 +++++- > include/linux/virtio_ring.h | 35 +++++++++ > 3 files changed, 204 insertions(+), 32 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 2f621e96b9ff..cf2840c7e500 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -95,6 +95,11 @@ struct vring_virtqueue { > /* How to notify other side. FIXME: commonalize hcalls! */ > bool (*notify)(struct virtqueue *vq); > > + /* DMA, allocation, and size information */ > + bool we_own_ring; > + size_t queue_size_in_bytes; > + dma_addr_t queue_dma_addr; > + > #ifdef DEBUG > /* They're supposed to lock for us. */ > unsigned int in_use; > @@ -878,36 +883,31 @@ irqreturn_t vring_interrupt(int irq, void *_vq) > } > EXPORT_SYMBOL_GPL(vring_interrupt); > > -struct virtqueue *vring_new_virtqueue(unsigned int index, > - unsigned int num, > - unsigned int vring_align, > - struct virtio_device *vdev, > - bool weak_barriers, > - void *pages, > - bool (*notify)(struct virtqueue *), > - void (*callback)(struct virtqueue *), > - const char *name) > +struct virtqueue *__vring_new_virtqueue(unsigned int index, > + struct vring vring, > + struct virtio_device *vdev, > + bool weak_barriers, > + bool (*notify)(struct virtqueue *), > + void (*callback)(struct virtqueue *), > + const char *name) > { > - struct vring_virtqueue *vq; > unsigned int i; > + struct vring_virtqueue *vq; > > - /* We assume num is a power of 2. */ > - if (num & (num - 1)) { > - dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num); > - return NULL; > - } > - > - vq = kmalloc(sizeof(*vq) + num * sizeof(struct vring_desc_state), > + vq = kmalloc(sizeof(*vq) + vring.num * sizeof(struct vring_desc_state), > GFP_KERNEL); > if (!vq) > return NULL; > > - vring_init(&vq->vring, num, pages, vring_align); > + vq->vring = vring; > vq->vq.callback = callback; > vq->vq.vdev = vdev; > vq->vq.name = name; > - vq->vq.num_free = num; > + vq->vq.num_free = vring.num; > vq->vq.index = index; > + vq->we_own_ring = false; > + vq->queue_dma_addr = 0; > + vq->queue_size_in_bytes = 0; > vq->notify = notify; > vq->weak_barriers = weak_barriers; > vq->broken = false; > @@ -932,18 +932,105 @@ struct virtqueue *vring_new_virtqueue(unsigned int index, > > /* Put everything in free lists. */ > vq->free_head = 0; > - for (i = 0; i < num-1; i++) > + for (i = 0; i < vring.num-1; i++) > vq->vring.desc[i].next = cpu_to_virtio16(vdev, i + 1); > - memset(vq->desc_state, 0, num * sizeof(struct vring_desc_state)); > + memset(vq->desc_state, 0, vring.num * sizeof(struct vring_desc_state)); > > return &vq->vq; > } > +EXPORT_SYMBOL_GPL(__vring_new_virtqueue); > + > +struct virtqueue *vring_create_virtqueue( > + unsigned int index, > + unsigned int num, > + unsigned int vring_align, > + struct virtio_device *vdev, > + bool weak_barriers, > + bool may_reduce_num, > + bool (*notify)(struct virtqueue *), > + void (*callback)(struct virtqueue *), > + const char *name) > +{ > + struct virtqueue *vq; > + void *queue; > + dma_addr_t dma_addr; > + size_t queue_size_in_bytes; > + struct vring vring; > + > + /* We assume num is a power of 2. */ > + if (num & (num - 1)) { > + dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num); > + return NULL; > + } > + > + /* TODO: allocate each queue chunk individually */ > + for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) { > + queue = dma_zalloc_coherent( > + vdev->dev.parent, vring_size(num, vring_align), > + &dma_addr, GFP_KERNEL|__GFP_NOWARN); I think that we should teach this one to use regular kmalloc if vring_use_dma_api is cleared. Not a must but it seems cleaner at this stage. > + if (queue) > + break; > + } > + > + if (!num) > + return NULL; > + > + if (!queue) { > + /* Try to get a single page. You are my only hope! */ > + queue = dma_zalloc_coherent( > + vdev->dev.parent, vring_size(num, vring_align), > + &dma_addr, GFP_KERNEL); > + } > + if (!queue) > + return NULL; > + > + queue_size_in_bytes = vring_size(num, vring_align); > + vring_init(&vring, num, queue, vring_align); > + > + vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers, > + notify, callback, name); > + if (!vq) { > + dma_free_coherent(vdev->dev.parent, > + queue_size_in_bytes, queue, > + dma_addr); > + return NULL; > + } > + > + to_vvq(vq)->queue_dma_addr = dma_addr; > + to_vvq(vq)->queue_size_in_bytes = queue_size_in_bytes; > + to_vvq(vq)->we_own_ring = true; > + > + return vq; > +} > +EXPORT_SYMBOL_GPL(vring_create_virtqueue); > + > +struct virtqueue *vring_new_virtqueue(unsigned int index, > + unsigned int num, > + unsigned int vring_align, > + struct virtio_device *vdev, > + bool weak_barriers, > + void *pages, > + bool (*notify)(struct virtqueue *vq), > + void (*callback)(struct virtqueue *vq), > + const char *name) > +{ > + struct vring vring; > + vring_init(&vring, num, pages, vring_align); > + return __vring_new_virtqueue(index, vring, vdev, weak_barriers, > + notify, callback, name); > +} > EXPORT_SYMBOL_GPL(vring_new_virtqueue); > > -void vring_del_virtqueue(struct virtqueue *vq) > +void vring_del_virtqueue(struct virtqueue *_vq) > { > - list_del(&vq->list); > - kfree(to_vvq(vq)); > + struct vring_virtqueue *vq = to_vvq(_vq); > + > + if (vq->we_own_ring) { > + dma_free_coherent(vring_dma_dev(vq), vq->queue_size_in_bytes, > + vq->vring.desc, vq->queue_dma_addr); > + } > + list_del(&_vq->list); > + kfree(vq); > } > EXPORT_SYMBOL_GPL(vring_del_virtqueue); > > @@ -1007,20 +1094,51 @@ void virtio_break_device(struct virtio_device *dev) > } > EXPORT_SYMBOL_GPL(virtio_break_device); > > -void *virtqueue_get_avail(struct virtqueue *_vq) > +dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq) > +{ > + struct vring_virtqueue *vq = to_vvq(_vq); > + > + BUG_ON(!vq->we_own_ring); > + > + if (vring_use_dma_api(vq)) > + return vq->queue_dma_addr; > + else > + return virt_to_phys(vq->vring.desc); > +} > +EXPORT_SYMBOL_GPL(virtqueue_get_desc_addr); > + > +dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq) > { > struct vring_virtqueue *vq = to_vvq(_vq); > > - return vq->vring.avail; > + BUG_ON(!vq->we_own_ring); > + > + if (vring_use_dma_api(vq)) > + return vq->queue_dma_addr + > + ((char *)vq->vring.avail - (char *)vq->vring.desc); > + else > + return virt_to_phys(vq->vring.avail); > } > -EXPORT_SYMBOL_GPL(virtqueue_get_avail); > +EXPORT_SYMBOL_GPL(virtqueue_get_avail_addr); > > -void *virtqueue_get_used(struct virtqueue *_vq) > +dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq) > { > struct vring_virtqueue *vq = to_vvq(_vq); > > - return vq->vring.used; > + BUG_ON(!vq->we_own_ring); > + > + if (vring_use_dma_api(vq)) > + return vq->queue_dma_addr + > + ((char *)vq->vring.used - (char *)vq->vring.desc); > + else > + return virt_to_phys(vq->vring.used); > +} > +EXPORT_SYMBOL_GPL(virtqueue_get_used_addr); > + > +const struct vring *virtqueue_get_vring(struct virtqueue *vq) > +{ > + return &to_vvq(vq)->vring; > } > -EXPORT_SYMBOL_GPL(virtqueue_get_used); > +EXPORT_SYMBOL_GPL(virtqueue_get_vring); > > MODULE_LICENSE("GPL"); > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > index 8f4d4bfa6d46..d5eb5479a425 100644 > --- a/include/linux/virtio.h > +++ b/include/linux/virtio.h > @@ -75,8 +75,27 @@ unsigned int virtqueue_get_vring_size(struct virtqueue *vq); > > bool virtqueue_is_broken(struct virtqueue *vq); > > -void *virtqueue_get_avail(struct virtqueue *vq); > -void *virtqueue_get_used(struct virtqueue *vq); > +const struct vring *virtqueue_get_vring(struct virtqueue *vq); > +dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq); > +dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq); > +dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq); > + > +/* > + * Legacy accessors -- in almost all cases, these are the wrong functions > + * to use. > + */ > +static inline void *virtqueue_get_desc(struct virtqueue *vq) > +{ > + return virtqueue_get_vring(vq)->desc; > +} > +static inline void *virtqueue_get_avail(struct virtqueue *vq) > +{ > + return virtqueue_get_vring(vq)->avail; > +} > +static inline void *virtqueue_get_used(struct virtqueue *vq) > +{ > + return virtqueue_get_vring(vq)->used; > +} > > /** > * virtio_device - representation of a device using virtio > diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h > index a156e2b6ccfe..e8d36938f09a 100644 > --- a/include/linux/virtio_ring.h > +++ b/include/linux/virtio_ring.h > @@ -59,6 +59,35 @@ static inline void virtio_store_mb(bool weak_barriers, > struct virtio_device; > struct virtqueue; > > +/* > + * Creates a virtqueue and allocates the descriptor ring. If > + * may_reduce_num is set, then this may allocate a smaller ring than > + * expected. The caller should query virtqueue_get_ring_size to learn > + * the actual size of the ring. > + */ > +struct virtqueue *vring_create_virtqueue(unsigned int index, > + unsigned int num, > + unsigned int vring_align, > + struct virtio_device *vdev, > + bool weak_barriers, > + bool may_reduce_num, > + bool (*notify)(struct virtqueue *vq), > + void (*callback)(struct virtqueue *vq), > + const char *name); > + > +/* Creates a virtqueue with a custom layout. */ > +struct virtqueue *__vring_new_virtqueue(unsigned int index, > + struct vring vring, > + struct virtio_device *vdev, > + bool weak_barriers, > + bool (*notify)(struct virtqueue *), > + void (*callback)(struct virtqueue *), > + const char *name); > + > +/* > + * Creates a virtqueue with a standard layout but a caller-allocated > + * ring. > + */ > struct virtqueue *vring_new_virtqueue(unsigned int index, > unsigned int num, > unsigned int vring_align, > @@ -68,7 +97,13 @@ struct virtqueue *vring_new_virtqueue(unsigned int index, > bool (*notify)(struct virtqueue *vq), > void (*callback)(struct virtqueue *vq), > const char *name); > + > +/* > + * Destroys a virtqueue. If created with vring_create_virtqueue, this > + * also frees the ring. > + */ > void vring_del_virtqueue(struct virtqueue *vq); > + > /* Filter out transport-specific feature bits. */ > void vring_transport_features(struct virtio_device *vdev); > > -- > 2.5.0 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization