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Diffstat (limited to 'hw/virtio.c')
-rw-r--r--hw/virtio.c38
1 files changed, 24 insertions, 14 deletions
diff --git a/hw/virtio.c b/hw/virtio.c
index 4475bb3e44..85312b3ebe 100644
--- a/hw/virtio.c
+++ b/hw/virtio.c
@@ -360,11 +360,26 @@ int virtqueue_avail_bytes(VirtQueue *vq, int in_bytes, int out_bytes)
return 0;
}
+void virtqueue_map_sg(struct iovec *sg, target_phys_addr_t *addr,
+ size_t num_sg, int is_write)
+{
+ unsigned int i;
+ target_phys_addr_t len;
+
+ for (i = 0; i < num_sg; i++) {
+ len = sg[i].iov_len;
+ sg[i].iov_base = cpu_physical_memory_map(addr[i], &len, is_write);
+ if (sg[i].iov_base == NULL || len != sg[i].iov_len) {
+ fprintf(stderr, "virtio: trying to map MMIO memory\n");
+ exit(1);
+ }
+ }
+}
+
int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
{
unsigned int i, head, max;
target_phys_addr_t desc_pa = vq->vring.desc;
- target_phys_addr_t len;
if (!virtqueue_num_heads(vq, vq->last_avail_idx))
return 0;
@@ -388,28 +403,19 @@ int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
i = 0;
}
+ /* Collect all the descriptors */
do {
struct iovec *sg;
- int is_write = 0;
if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_WRITE) {
elem->in_addr[elem->in_num] = vring_desc_addr(desc_pa, i);
sg = &elem->in_sg[elem->in_num++];
- is_write = 1;
- } else
+ } else {
+ elem->out_addr[elem->out_num] = vring_desc_addr(desc_pa, i);
sg = &elem->out_sg[elem->out_num++];
+ }
- /* Grab the first descriptor, and check it's OK. */
sg->iov_len = vring_desc_len(desc_pa, i);
- len = sg->iov_len;
-
- sg->iov_base = cpu_physical_memory_map(vring_desc_addr(desc_pa, i),
- &len, is_write);
-
- if (sg->iov_base == NULL || len != sg->iov_len) {
- fprintf(stderr, "virtio: trying to map MMIO memory\n");
- exit(1);
- }
/* If we've got too many, that implies a descriptor loop. */
if ((elem->in_num + elem->out_num) > max) {
@@ -418,6 +424,10 @@ int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
}
} while ((i = virtqueue_next_desc(desc_pa, i, max)) != max);
+ /* Now map what we have collected */
+ virtqueue_map_sg(elem->in_sg, elem->in_addr, elem->in_num, 1);
+ virtqueue_map_sg(elem->out_sg, elem->out_addr, elem->out_num, 0);
+
elem->index = head;
vq->inuse++;