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dataplane: change vring API to use VirtQueueElement

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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Paolo Bonzini 2013-12-10 13:27:00 +01:00 • committed by Stefan Hajnoczi
parent 781c117f37
commit 8c1b566fd1
3 changed files with 72 additions and 76 deletions
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56
hw/virtio/dataplane/vring.c
View file

@ -111,29 +111,32 @@ bool vring_should_notify(VirtIODevice *vdev, Vring *vring)
}
static int get_desc(Vring *vring,
struct iovec iov[], struct iovec *iov_end,
unsigned int *out_num, unsigned int *in_num,
static int get_desc(Vring *vring, VirtQueueElement *elem,
struct vring_desc *desc)
{
unsigned *num;
struct iovec *iov;
hwaddr *addr;
if (desc->flags & VRING_DESC_F_WRITE) {
num = in_num;
num = &elem->in_num;
iov = &elem->in_sg[*num];
addr = &elem->in_addr[*num];
} else {
num = out_num;
num = &elem->out_num;
iov = &elem->out_sg[*num];
addr = &elem->out_addr[*num];
/* If it's an output descriptor, they're all supposed
* to come before any input descriptors. */
if (unlikely(*in_num)) {
if (unlikely(elem->in_num)) {
error_report("Descriptor has out after in");
return -EFAULT;
}
}
/* Stop for now if there are not enough iovecs available. */
iov += *in_num + *out_num;
if (iov >= iov_end) {
if (*num >= VIRTQUEUE_MAX_SIZE) {
return -ENOBUFS;
}
@ -147,14 +150,13 @@ static int get_desc(Vring *vring,
}
iov->iov_len = desc->len;
*addr = desc->addr;
*num += 1;
return 0;
}
/* This is stolen from linux/drivers/vhost/vhost.c. */
static int get_indirect(Vring *vring,
struct iovec iov[], struct iovec *iov_end,
unsigned int *out_num, unsigned int *in_num,
static int get_indirect(Vring *vring, VirtQueueElement *elem,
struct vring_desc *indirect)
{
struct vring_desc desc;
@ -212,7 +214,7 @@ static int get_indirect(Vring *vring,
return -EFAULT;
}
ret = get_desc(vring, iov, iov_end, out_num, in_num, &desc);
ret = get_desc(vring, elem, &desc);
if (ret < 0) {
vring->broken |= (ret == -EFAULT);
return ret;
@ -222,6 +224,11 @@ static int get_indirect(Vring *vring,
return 0;
}
void vring_free_element(VirtQueueElement *elem)
{
g_slice_free(VirtQueueElement, elem);
}
/* This looks in the virtqueue and for the first available buffer, and converts
* it to an iovec for convenient access. Since descriptors consist of some
* number of output then some number of input descriptors, it's actually two
@ -234,12 +241,12 @@ static int get_indirect(Vring *vring,
* Stolen from linux/drivers/vhost/vhost.c.
*/
int vring_pop(VirtIODevice *vdev, Vring *vring,
struct iovec iov[], struct iovec *iov_end,
unsigned int *out_num, unsigned int *in_num)
VirtQueueElement **p_elem)
{
struct vring_desc desc;
unsigned int i, head, found = 0, num = vring->vr.num;
uint16_t avail_idx, last_avail_idx;
VirtQueueElement *elem = NULL;
int ret;
/* If there was a fatal error then refuse operation */
@ -273,6 +280,10 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
* the index we've seen. */
head = vring->vr.avail->ring[last_avail_idx % num];
elem = g_slice_new(VirtQueueElement);
elem->index = head;
elem->in_num = elem->out_num = 0;
/* If their number is silly, that's an error. */
if (unlikely(head >= num)) {
error_report("Guest says index %u > %u is available", head, num);
@ -284,9 +295,6 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
vring_avail_event(&vring->vr) = vring->vr.avail->idx;
}
/* When we start there are none of either input nor output. */
*out_num = *in_num = 0;
i = head;
do {
if (unlikely(i >= num)) {
@ -306,14 +314,14 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
barrier();
if (desc.flags & VRING_DESC_F_INDIRECT) {
int ret = get_indirect(vring, iov, iov_end, out_num, in_num, &desc);
int ret = get_indirect(vring, elem, &desc);
if (ret < 0) {
goto out;
}
continue;
}
ret = get_desc(vring, iov, iov_end, out_num, in_num, &desc);
ret = get_desc(vring, elem, &desc);
if (ret < 0) {
goto out;
}
@ -323,6 +331,7 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
/* On success, increment avail index. */
vring->last_avail_idx++;
*p_elem = elem;
return head;
out:
@ -330,6 +339,10 @@ out:
if (ret == -EFAULT) {
vring->broken = true;
}
if (elem) {
vring_free_element(elem);
}
*p_elem = NULL;
return ret;
}
@ -337,11 +350,14 @@ out:
*
* Stolen from linux/drivers/vhost/vhost.c.
*/
void vring_push(Vring *vring, unsigned int head, int len)
void vring_push(Vring *vring, VirtQueueElement *elem, int len)
{
struct vring_used_elem *used;
unsigned int head = elem->index;
uint16_t new;
vring_free_element(elem);
/* Don't touch vring if a fatal error occurred */
if (vring->broken) {
return;