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authorJason Wang <jasowang@redhat.com>2015-07-17 15:19:18 +0800
committerMichael S. Tsirkin <mst@redhat.com>2015-07-20 14:19:41 +0300
commitfeb93f361739071778ca2d23df3876db399548f7 (patch)
tree4e343f13bc3292507b1e08e6cc5f8c29def4f552
parentd345ed2da3279b015605823397235b8c5ca5251f (diff)
downloadqemu-arm-feb93f361739071778ca2d23df3876db399548f7.tar.gz
virtio-net: unbreak any layout
Commit 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 ("virtio-net: byteswap virtio-net header") breaks any layout by requiring out_sg[0].iov_len >= n->guest_hdr_len. Fixing this by copying header to temporary buffer if swap is needed, and then use this buffer as part of out_sg. Fixes 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 ("virtio-net: byteswap virtio-net header") Cc: qemu-stable@nongnu.org Cc: clg@fr.ibm.com Signed-off-by: Jason Wang <jasowang@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
-rw-r--r--hw/net/virtio-net.c23
-rw-r--r--include/hw/virtio/virtio-access.h9
2 files changed, 27 insertions, 5 deletions
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index e3c2db3250..9f7e91ddce 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1142,7 +1142,8 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q)
ssize_t ret, len;
unsigned int out_num = elem.out_num;
struct iovec *out_sg = &elem.out_sg[0];
- struct iovec sg[VIRTQUEUE_MAX_SIZE];
+ struct iovec sg[VIRTQUEUE_MAX_SIZE], sg2[VIRTQUEUE_MAX_SIZE + 1];
+ struct virtio_net_hdr_mrg_rxbuf mhdr;
if (out_num < 1) {
error_report("virtio-net header not in first element");
@@ -1150,13 +1151,25 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q)
}
if (n->has_vnet_hdr) {
- if (out_sg[0].iov_len < n->guest_hdr_len) {
+ if (iov_to_buf(out_sg, out_num, 0, &mhdr, n->guest_hdr_len) <
+ n->guest_hdr_len) {
error_report("virtio-net header incorrect");
exit(1);
}
- virtio_net_hdr_swap(vdev, (void *) out_sg[0].iov_base);
+ if (virtio_needs_swap(vdev)) {
+ virtio_net_hdr_swap(vdev, (void *) &mhdr);
+ sg2[0].iov_base = &mhdr;
+ sg2[0].iov_len = n->guest_hdr_len;
+ out_num = iov_copy(&sg2[1], ARRAY_SIZE(sg2) - 1,
+ out_sg, out_num,
+ n->guest_hdr_len, -1);
+ if (out_num == VIRTQUEUE_MAX_SIZE) {
+ goto drop;
+ }
+ out_num += 1;
+ out_sg = sg2;
+ }
}
-
/*
* If host wants to see the guest header as is, we can
* pass it on unchanged. Otherwise, copy just the parts
@@ -1186,7 +1199,7 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q)
}
len += ret;
-
+drop:
virtqueue_push(q->tx_vq, &elem, 0);
virtio_notify(vdev, q->tx_vq);
diff --git a/include/hw/virtio/virtio-access.h b/include/hw/virtio/virtio-access.h
index cee5dd70c9..1ec1dfdb6c 100644
--- a/include/hw/virtio/virtio-access.h
+++ b/include/hw/virtio/virtio-access.h
@@ -143,6 +143,15 @@ static inline uint64_t virtio_ldq_p(VirtIODevice *vdev, const void *ptr)
}
}
+static inline bool virtio_needs_swap(VirtIODevice *vdev)
+{
+#ifdef HOST_WORDS_BIGENDIAN
+ return virtio_access_is_big_endian(vdev) ? false : true;
+#else
+ return virtio_access_is_big_endian(vdev) ? true : false;
+#endif
+}
+
static inline uint16_t virtio_tswap16(VirtIODevice *vdev, uint16_t s)
{
#ifdef HOST_WORDS_BIGENDIAN