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virtio: Factor virtqueue_map_sg out

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Separate the mapping of requests to host memory from the descriptor iteration.
The next patch will make use of it in a different context.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2010-08-03 16:54:38 +02:00
parent 02a89b2190
commit 42fb2e0720
2 changed files with 28 additions and 15 deletions
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40
hw/virtio.c
View File

@ -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;
@ -388,29 +403,20 @@ 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);
}
sg->iov_len = vring_desc_len(desc_pa, i);
/* If we've got too many, that implies a descriptor loop. */
if ((elem->in_num + elem->out_num) > max) {
fprintf(stderr, "Looped descriptor");
@ -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++;

3
hw/virtio.h
View File

@ -81,6 +81,7 @@ typedef struct VirtQueueElement
unsigned int out_num;
unsigned int in_num;
target_phys_addr_t in_addr[VIRTQUEUE_MAX_SIZE];
target_phys_addr_t out_addr[VIRTQUEUE_MAX_SIZE];
struct iovec in_sg[VIRTQUEUE_MAX_SIZE];
struct iovec out_sg[VIRTQUEUE_MAX_SIZE];
} VirtQueueElement;
@ -142,6 +143,8 @@ void virtqueue_flush(VirtQueue *vq, unsigned int count);
void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
unsigned int len, unsigned int idx);
void virtqueue_map_sg(struct iovec *sg, target_phys_addr_t *addr,
size_t num_sg, int is_write);
int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem);
int virtqueue_avail_bytes(VirtQueue *vq, int in_bytes, int out_bytes);