virtio: Add improved queue allocation API
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@kernel.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Andy Lutomirski
Michael S. Tsirkin
Родитель
780bc7903a
Коммит
2a2d1382fe
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@ -95,6 +95,11 @@ struct vring_virtqueue {
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/* How to notify other side. FIXME: commonalize hcalls! */
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bool (*notify)(struct virtqueue *vq);
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/* DMA, allocation, and size information */
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bool we_own_ring;
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size_t queue_size_in_bytes;
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dma_addr_t queue_dma_addr;
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#ifdef DEBUG
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/* They're supposed to lock for us. */
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unsigned int in_use;
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@ -878,36 +883,31 @@ irqreturn_t vring_interrupt(int irq, void *_vq)
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}
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EXPORT_SYMBOL_GPL(vring_interrupt);
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struct virtqueue *vring_new_virtqueue(unsigned int index,
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unsigned int num,
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unsigned int vring_align,
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struct virtio_device *vdev,
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bool weak_barriers,
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void *pages,
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bool (*notify)(struct virtqueue *),
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void (*callback)(struct virtqueue *),
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const char *name)
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struct virtqueue *__vring_new_virtqueue(unsigned int index,
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struct vring vring,
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struct virtio_device *vdev,
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bool weak_barriers,
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bool (*notify)(struct virtqueue *),
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void (*callback)(struct virtqueue *),
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const char *name)
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{
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struct vring_virtqueue *vq;
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unsigned int i;
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struct vring_virtqueue *vq;
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/* We assume num is a power of 2. */
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if (num & (num - 1)) {
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dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num);
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return NULL;
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}
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vq = kmalloc(sizeof(*vq) + num * sizeof(struct vring_desc_state),
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vq = kmalloc(sizeof(*vq) + vring.num * sizeof(struct vring_desc_state),
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GFP_KERNEL);
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if (!vq)
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return NULL;
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vring_init(&vq->vring, num, pages, vring_align);
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vq->vring = vring;
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vq->vq.callback = callback;
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vq->vq.vdev = vdev;
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vq->vq.name = name;
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vq->vq.num_free = num;
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vq->vq.num_free = vring.num;
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vq->vq.index = index;
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vq->we_own_ring = false;
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vq->queue_dma_addr = 0;
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vq->queue_size_in_bytes = 0;
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vq->notify = notify;
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vq->weak_barriers = weak_barriers;
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vq->broken = false;
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@ -932,18 +932,145 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
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/* Put everything in free lists. */
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vq->free_head = 0;
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for (i = 0; i < num-1; i++)
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for (i = 0; i < vring.num-1; i++)
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vq->vring.desc[i].next = cpu_to_virtio16(vdev, i + 1);
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memset(vq->desc_state, 0, num * sizeof(struct vring_desc_state));
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memset(vq->desc_state, 0, vring.num * sizeof(struct vring_desc_state));
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return &vq->vq;
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}
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EXPORT_SYMBOL_GPL(__vring_new_virtqueue);
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static void *vring_alloc_queue(struct virtio_device *vdev, size_t size,
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dma_addr_t *dma_handle, gfp_t flag)
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{
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if (vring_use_dma_api(vdev)) {
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return dma_alloc_coherent(vdev->dev.parent, size,
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dma_handle, flag);
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} else {
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void *queue = alloc_pages_exact(PAGE_ALIGN(size), flag);
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if (queue) {
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phys_addr_t phys_addr = virt_to_phys(queue);
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*dma_handle = (dma_addr_t)phys_addr;
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/*
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* Sanity check: make sure we dind't truncate
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* the address. The only arches I can find that
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* have 64-bit phys_addr_t but 32-bit dma_addr_t
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* are certain non-highmem MIPS and x86
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* configurations, but these configurations
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* should never allocate physical pages above 32
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* bits, so this is fine. Just in case, throw a
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* warning and abort if we end up with an
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* unrepresentable address.
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*/
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if (WARN_ON_ONCE(*dma_handle != phys_addr)) {
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free_pages_exact(queue, PAGE_ALIGN(size));
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return NULL;
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}
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}
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return queue;
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}
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}
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static void vring_free_queue(struct virtio_device *vdev, size_t size,
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void *queue, dma_addr_t dma_handle)
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{
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if (vring_use_dma_api(vdev)) {
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dma_free_coherent(vdev->dev.parent, size, queue, dma_handle);
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} else {
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free_pages_exact(queue, PAGE_ALIGN(size));
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}
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}
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struct virtqueue *vring_create_virtqueue(
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unsigned int index,
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unsigned int num,
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unsigned int vring_align,
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struct virtio_device *vdev,
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bool weak_barriers,
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bool may_reduce_num,
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bool (*notify)(struct virtqueue *),
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void (*callback)(struct virtqueue *),
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const char *name)
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{
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struct virtqueue *vq;
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void *queue;
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dma_addr_t dma_addr;
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size_t queue_size_in_bytes;
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struct vring vring;
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/* We assume num is a power of 2. */
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if (num & (num - 1)) {
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dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num);
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return NULL;
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}
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/* TODO: allocate each queue chunk individually */
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for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) {
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queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
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&dma_addr,
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GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
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if (queue)
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break;
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}
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if (!num)
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return NULL;
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if (!queue) {
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/* Try to get a single page. You are my only hope! */
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queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
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&dma_addr, GFP_KERNEL|__GFP_ZERO);
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}
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if (!queue)
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return NULL;
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queue_size_in_bytes = vring_size(num, vring_align);
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vring_init(&vring, num, queue, vring_align);
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vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers,
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notify, callback, name);
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if (!vq) {
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vring_free_queue(vdev, queue_size_in_bytes, queue,
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dma_addr);
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return NULL;
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}
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to_vvq(vq)->queue_dma_addr = dma_addr;
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to_vvq(vq)->queue_size_in_bytes = queue_size_in_bytes;
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to_vvq(vq)->we_own_ring = true;
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return vq;
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}
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EXPORT_SYMBOL_GPL(vring_create_virtqueue);
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struct virtqueue *vring_new_virtqueue(unsigned int index,
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unsigned int num,
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unsigned int vring_align,
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struct virtio_device *vdev,
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bool weak_barriers,
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void *pages,
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bool (*notify)(struct virtqueue *vq),
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void (*callback)(struct virtqueue *vq),
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const char *name)
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{
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struct vring vring;
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vring_init(&vring, num, pages, vring_align);
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return __vring_new_virtqueue(index, vring, vdev, weak_barriers,
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notify, callback, name);
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}
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EXPORT_SYMBOL_GPL(vring_new_virtqueue);
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void vring_del_virtqueue(struct virtqueue *vq)
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void vring_del_virtqueue(struct virtqueue *_vq)
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{
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list_del(&vq->list);
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kfree(to_vvq(vq));
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struct vring_virtqueue *vq = to_vvq(_vq);
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if (vq->we_own_ring) {
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vring_free_queue(vq->vq.vdev, vq->queue_size_in_bytes,
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vq->vring.desc, vq->queue_dma_addr);
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}
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list_del(&_vq->list);
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kfree(vq);
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}
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EXPORT_SYMBOL_GPL(vring_del_virtqueue);
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@ -1007,20 +1134,42 @@ void virtio_break_device(struct virtio_device *dev)
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}
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EXPORT_SYMBOL_GPL(virtio_break_device);
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void *virtqueue_get_avail(struct virtqueue *_vq)
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dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq)
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{
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struct vring_virtqueue *vq = to_vvq(_vq);
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return vq->vring.avail;
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}
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EXPORT_SYMBOL_GPL(virtqueue_get_avail);
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BUG_ON(!vq->we_own_ring);
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void *virtqueue_get_used(struct virtqueue *_vq)
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return vq->queue_dma_addr;
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}
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EXPORT_SYMBOL_GPL(virtqueue_get_desc_addr);
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dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq)
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{
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struct vring_virtqueue *vq = to_vvq(_vq);
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return vq->vring.used;
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BUG_ON(!vq->we_own_ring);
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return vq->queue_dma_addr +
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((char *)vq->vring.avail - (char *)vq->vring.desc);
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}
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EXPORT_SYMBOL_GPL(virtqueue_get_used);
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EXPORT_SYMBOL_GPL(virtqueue_get_avail_addr);
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dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq)
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{
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struct vring_virtqueue *vq = to_vvq(_vq);
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BUG_ON(!vq->we_own_ring);
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return vq->queue_dma_addr +
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((char *)vq->vring.used - (char *)vq->vring.desc);
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}
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EXPORT_SYMBOL_GPL(virtqueue_get_used_addr);
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const struct vring *virtqueue_get_vring(struct virtqueue *vq)
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{
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return &to_vvq(vq)->vring;
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}
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EXPORT_SYMBOL_GPL(virtqueue_get_vring);
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MODULE_LICENSE("GPL");
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@ -75,8 +75,27 @@ unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
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bool virtqueue_is_broken(struct virtqueue *vq);
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void *virtqueue_get_avail(struct virtqueue *vq);
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void *virtqueue_get_used(struct virtqueue *vq);
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const struct vring *virtqueue_get_vring(struct virtqueue *vq);
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dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq);
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dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq);
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dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq);
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/*
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* Legacy accessors -- in almost all cases, these are the wrong functions
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* to use.
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*/
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static inline void *virtqueue_get_desc(struct virtqueue *vq)
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{
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return virtqueue_get_vring(vq)->desc;
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}
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static inline void *virtqueue_get_avail(struct virtqueue *vq)
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{
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return virtqueue_get_vring(vq)->avail;
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}
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static inline void *virtqueue_get_used(struct virtqueue *vq)
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{
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return virtqueue_get_vring(vq)->used;
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}
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/**
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* virtio_device - representation of a device using virtio
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@ -59,6 +59,35 @@ static inline void virtio_store_mb(bool weak_barriers,
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struct virtio_device;
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struct virtqueue;
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/*
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* Creates a virtqueue and allocates the descriptor ring. If
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* may_reduce_num is set, then this may allocate a smaller ring than
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* expected. The caller should query virtqueue_get_ring_size to learn
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* the actual size of the ring.
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*/
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struct virtqueue *vring_create_virtqueue(unsigned int index,
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unsigned int num,
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unsigned int vring_align,
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struct virtio_device *vdev,
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bool weak_barriers,
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bool may_reduce_num,
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bool (*notify)(struct virtqueue *vq),
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void (*callback)(struct virtqueue *vq),
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const char *name);
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/* Creates a virtqueue with a custom layout. */
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struct virtqueue *__vring_new_virtqueue(unsigned int index,
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struct vring vring,
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struct virtio_device *vdev,
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bool weak_barriers,
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bool (*notify)(struct virtqueue *),
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void (*callback)(struct virtqueue *),
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const char *name);
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/*
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* Creates a virtqueue with a standard layout but a caller-allocated
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* ring.
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*/
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struct virtqueue *vring_new_virtqueue(unsigned int index,
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unsigned int num,
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unsigned int vring_align,
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@ -68,7 +97,13 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
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bool (*notify)(struct virtqueue *vq),
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void (*callback)(struct virtqueue *vq),
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const char *name);
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/*
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* Destroys a virtqueue. If created with vring_create_virtqueue, this
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* also frees the ring.
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*/
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void vring_del_virtqueue(struct virtqueue *vq);
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/* Filter out transport-specific feature bits. */
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void vring_transport_features(struct virtio_device *vdev);
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