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authorPaolo Bonzini <pbonzini@redhat.com>2013-12-10 13:26:58 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2013-12-20 09:11:57 +0100
commit4d684832e54afe971fd8f94cb830ec1e135648e7 (patch)
tree12a100775c2c767a4bd857e054d7d9c32fafa00e /hw/virtio
parente50d7607f1800c9f9c576229c6119e4c82f456d6 (diff)
vring: create a common function to parse descriptors
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'hw/virtio')
-rw-r--r--hw/virtio/dataplane/vring.c113
1 files changed, 51 insertions, 62 deletions
diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
index 351a343806..8294f36d07 100644
--- a/hw/virtio/dataplane/vring.c
+++ b/hw/virtio/dataplane/vring.c
@@ -110,6 +110,47 @@ bool vring_should_notify(VirtIODevice *vdev, Vring *vring)
return vring_need_event(vring_used_event(&vring->vr), new, old);
}
+
+static int get_desc(Vring *vring,
+ struct iovec iov[], struct iovec *iov_end,
+ unsigned int *out_num, unsigned int *in_num,
+ struct vring_desc *desc)
+{
+ unsigned *num;
+
+ if (desc->flags & VRING_DESC_F_WRITE) {
+ num = in_num;
+ } else {
+ num = out_num;
+
+ /* If it's an output descriptor, they're all supposed
+ * to come before any input descriptors. */
+ if (unlikely(*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) {
+ return -ENOBUFS;
+ }
+
+ /* TODO handle non-contiguous memory across region boundaries */
+ iov->iov_base = hostmem_lookup(&vring->hostmem, desc->addr, desc->len,
+ desc->flags & VRING_DESC_F_WRITE);
+ if (!iov->iov_base) {
+ error_report("Failed to map descriptor addr %#" PRIx64 " len %u",
+ (uint64_t)desc->addr, desc->len);
+ return -EFAULT;
+ }
+
+ iov->iov_len = desc->len;
+ *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,
@@ -118,6 +159,7 @@ static int get_indirect(Vring *vring,
{
struct vring_desc desc;
unsigned int i = 0, count, found = 0;
+ int ret;
/* Sanity check */
if (unlikely(indirect->len % sizeof(desc))) {
@@ -170,36 +212,10 @@ static int get_indirect(Vring *vring,
return -EFAULT;
}
- /* Stop for now if there are not enough iovecs available. */
- if (iov >= iov_end) {
- return -ENOBUFS;
- }
-
- iov->iov_base = hostmem_lookup(&vring->hostmem, desc.addr, desc.len,
- desc.flags & VRING_DESC_F_WRITE);
- if (!iov->iov_base) {
- error_report("Failed to map indirect descriptor"
- "addr %#" PRIx64 " len %u",
- (uint64_t)desc.addr, desc.len);
- vring->broken = true;
- return -EFAULT;
- }
- iov->iov_len = desc.len;
- iov++;
-
- /* If this is an input descriptor, increment that count. */
- if (desc.flags & VRING_DESC_F_WRITE) {
- *in_num += 1;
- } else {
- /* If it's an output descriptor, they're all supposed
- * to come before any input descriptors. */
- if (unlikely(*in_num)) {
- error_report("Indirect descriptor "
- "has out after in: idx %u", i);
- vring->broken = true;
- return -EFAULT;
- }
- *out_num += 1;
+ ret = get_desc(vring, iov, iov_end, out_num, in_num, &desc);
+ if (ret < 0) {
+ vring->broken |= (ret == -EFAULT);
+ return ret;
}
i = desc.next;
} while (desc.flags & VRING_DESC_F_NEXT);
@@ -224,6 +240,7 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
struct vring_desc desc;
unsigned int i, head, found = 0, num = vring->vr.num;
uint16_t avail_idx, last_avail_idx;
+ int ret;
/* If there was a fatal error then refuse operation */
if (vring->broken) {
@@ -294,40 +311,12 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
continue;
}
- /* If there are not enough iovecs left, stop for now. The caller
- * should check if there are more descs available once they have dealt
- * with the current set.
- */
- if (iov >= iov_end) {
- return -ENOBUFS;
+ ret = get_desc(vring, iov, iov_end, out_num, in_num, &desc);
+ if (ret < 0) {
+ vring->broken |= (ret == -EFAULT);
+ return ret;
}
- /* TODO handle non-contiguous memory across region boundaries */
- iov->iov_base = hostmem_lookup(&vring->hostmem, desc.addr, desc.len,
- desc.flags & VRING_DESC_F_WRITE);
- if (!iov->iov_base) {
- error_report("Failed to map vring desc addr %#" PRIx64 " len %u",
- (uint64_t)desc.addr, desc.len);
- vring->broken = true;
- return -EFAULT;
- }
- iov->iov_len = desc.len;
- iov++;
-
- if (desc.flags & VRING_DESC_F_WRITE) {
- /* If this is an input descriptor,
- * increment that count. */
- *in_num += 1;
- } else {
- /* If it's an output descriptor, they're all supposed
- * to come before any input descriptors. */
- if (unlikely(*in_num)) {
- error_report("Descriptor has out after in: idx %d", i);
- vring->broken = true;
- return -EFAULT;
- }
- *out_num += 1;
- }
i = desc.next;
} while (desc.flags & VRING_DESC_F_NEXT);