virtio: use address_space_map/unmap to access descriptors
This makes little difference, but it makes the code change smaller for the next patch that introduces MemoryRegionCache. This is because map/unmap are similar to MemoryRegionCache init/destroy. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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e6a830d6eb
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9796d0ac8f
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@ -120,10 +120,9 @@ void virtio_queue_update_rings(VirtIODevice *vdev, int n)
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}
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static void vring_desc_read(VirtIODevice *vdev, VRingDesc *desc,
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hwaddr desc_pa, int i)
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uint8_t *desc_ptr, int i)
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{
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address_space_read(vdev->dma_as, desc_pa + i * sizeof(VRingDesc),
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MEMTXATTRS_UNSPECIFIED, (void *)desc, sizeof(VRingDesc));
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memcpy(desc, desc_ptr + i * sizeof(VRingDesc), sizeof(VRingDesc));
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virtio_tswap64s(vdev, &desc->addr);
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virtio_tswap32s(vdev, &desc->len);
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virtio_tswap16s(vdev, &desc->flags);
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@ -408,7 +407,7 @@ enum {
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};
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static int virtqueue_read_next_desc(VirtIODevice *vdev, VRingDesc *desc,
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hwaddr desc_pa, unsigned int max,
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void *desc_ptr, unsigned int max,
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unsigned int *next)
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{
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/* If this descriptor says it doesn't chain, we're done. */
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@ -426,7 +425,7 @@ static int virtqueue_read_next_desc(VirtIODevice *vdev, VRingDesc *desc,
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return VIRTQUEUE_READ_DESC_ERROR;
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}
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vring_desc_read(vdev, desc, desc_pa, *next);
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vring_desc_read(vdev, desc, desc_ptr, *next);
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return VIRTQUEUE_READ_DESC_MORE;
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}
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@ -434,31 +433,41 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
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unsigned int *out_bytes,
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unsigned max_in_bytes, unsigned max_out_bytes)
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{
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unsigned int idx;
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VirtIODevice *vdev = vq->vdev;
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unsigned int max, idx;
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unsigned int total_bufs, in_total, out_total;
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void *vring_desc_ptr;
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void *indirect_desc_ptr = NULL;
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hwaddr len = 0;
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int rc;
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idx = vq->last_avail_idx;
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total_bufs = in_total = out_total = 0;
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while ((rc = virtqueue_num_heads(vq, idx)) > 0) {
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VirtIODevice *vdev = vq->vdev;
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unsigned int max, num_bufs, indirect = 0;
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VRingDesc desc;
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hwaddr desc_pa;
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unsigned int i;
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max = vq->vring.num;
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len = max * sizeof(VRingDesc);
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vring_desc_ptr = address_space_map(vdev->dma_as, vq->vring.desc, &len, false);
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if (len < max * sizeof(VRingDesc)) {
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virtio_error(vdev, "Cannot map descriptor ring");
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goto err;
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}
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while ((rc = virtqueue_num_heads(vq, idx)) > 0) {
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void *desc_ptr = vring_desc_ptr;
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unsigned int num_bufs;
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VRingDesc desc;
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unsigned int i;
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num_bufs = total_bufs;
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if (!virtqueue_get_head(vq, idx++, &i)) {
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goto err;
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}
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desc_pa = vq->vring.desc;
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vring_desc_read(vdev, &desc, desc_pa, i);
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vring_desc_read(vdev, &desc, desc_ptr, i);
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if (desc.flags & VRING_DESC_F_INDIRECT) {
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len = desc.len;
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if (desc.len % sizeof(VRingDesc)) {
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virtio_error(vdev, "Invalid size for indirect buffer table");
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goto err;
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@ -471,11 +480,17 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
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}
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/* loop over the indirect descriptor table */
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indirect = 1;
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indirect_desc_ptr = address_space_map(vdev->dma_as, desc.addr,
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&len, false);
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desc_ptr = indirect_desc_ptr;
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if (len < desc.len) {
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virtio_error(vdev, "Cannot map indirect buffer");
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goto err;
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}
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max = desc.len / sizeof(VRingDesc);
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desc_pa = desc.addr;
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num_bufs = i = 0;
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vring_desc_read(vdev, &desc, desc_pa, i);
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vring_desc_read(vdev, &desc, desc_ptr, i);
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}
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do {
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@ -494,17 +509,20 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
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goto done;
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}
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rc = virtqueue_read_next_desc(vdev, &desc, desc_pa, max, &i);
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rc = virtqueue_read_next_desc(vdev, &desc, desc_ptr, max, &i);
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} while (rc == VIRTQUEUE_READ_DESC_MORE);
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if (rc == VIRTQUEUE_READ_DESC_ERROR) {
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goto err;
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}
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if (!indirect)
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total_bufs = num_bufs;
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else
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if (desc_ptr == indirect_desc_ptr) {
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address_space_unmap(vdev->dma_as, desc_ptr, len, false, 0);
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indirect_desc_ptr = NULL;
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total_bufs++;
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} else {
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total_bufs = num_bufs;
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}
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}
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if (rc < 0) {
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@ -512,6 +530,10 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
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}
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done:
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if (indirect_desc_ptr) {
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address_space_unmap(vdev->dma_as, indirect_desc_ptr, len, false, 0);
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}
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address_space_unmap(vdev->dma_as, vring_desc_ptr, len, false, 0);
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if (in_bytes) {
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*in_bytes = in_total;
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}
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@ -651,9 +673,12 @@ static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_nu
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void *virtqueue_pop(VirtQueue *vq, size_t sz)
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{
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unsigned int i, head, max;
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hwaddr desc_pa = vq->vring.desc;
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void *vring_desc_ptr;
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void *indirect_desc_ptr = NULL;
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void *desc_ptr;
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hwaddr len;
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VirtIODevice *vdev = vq->vdev;
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VirtQueueElement *elem;
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VirtQueueElement *elem = NULL;
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unsigned out_num, in_num;
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hwaddr addr[VIRTQUEUE_MAX_SIZE];
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struct iovec iov[VIRTQUEUE_MAX_SIZE];
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@ -689,18 +714,34 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
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}
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i = head;
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vring_desc_read(vdev, &desc, desc_pa, i);
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len = max * sizeof(VRingDesc);
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vring_desc_ptr = address_space_map(vdev->dma_as, vq->vring.desc, &len, false);
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if (len < max * sizeof(VRingDesc)) {
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virtio_error(vdev, "Cannot map descriptor ring");
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goto done;
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}
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desc_ptr = vring_desc_ptr;
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vring_desc_read(vdev, &desc, desc_ptr, i);
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if (desc.flags & VRING_DESC_F_INDIRECT) {
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if (desc.len % sizeof(VRingDesc)) {
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virtio_error(vdev, "Invalid size for indirect buffer table");
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return NULL;
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goto done;
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}
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/* loop over the indirect descriptor table */
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len = desc.len;
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indirect_desc_ptr = address_space_map(vdev->dma_as, desc.addr, &len, false);
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desc_ptr = indirect_desc_ptr;
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if (len < desc.len) {
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virtio_error(vdev, "Cannot map indirect buffer");
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goto done;
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}
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max = desc.len / sizeof(VRingDesc);
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desc_pa = desc.addr;
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i = 0;
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vring_desc_read(vdev, &desc, desc_pa, i);
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vring_desc_read(vdev, &desc, desc_ptr, i);
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}
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/* Collect all the descriptors */
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@ -731,7 +772,7 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
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goto err_undo_map;
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}
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rc = virtqueue_read_next_desc(vdev, &desc, desc_pa, max, &i);
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rc = virtqueue_read_next_desc(vdev, &desc, desc_ptr, max, &i);
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} while (rc == VIRTQUEUE_READ_DESC_MORE);
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if (rc == VIRTQUEUE_READ_DESC_ERROR) {
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@ -753,11 +794,17 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
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vq->inuse++;
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trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
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done:
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if (indirect_desc_ptr) {
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address_space_unmap(vdev->dma_as, indirect_desc_ptr, len, false, 0);
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}
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address_space_unmap(vdev->dma_as, vring_desc_ptr, len, false, 0);
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return elem;
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err_undo_map:
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virtqueue_undo_map_desc(out_num, in_num, iov);
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return NULL;
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goto done;
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}
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/* virtqueue_drop_all:
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