ShuriZma
/
xemu
mirror of https://github.com/xemu-project/xemu.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

virtio-net: unbreak any layout 

Commit 032a74a1c0
("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 032a74a1c0
("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>
This commit is contained in:
Jason Wang 2015-07-17 15:19:18 +08:00 committed by Michael S. Tsirkin
parent d345ed2da3
commit feb93f3617
2 changed files with 27 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
hw/net/virtio-net.c
View File

@ -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);

9
include/hw/virtio/virtio-access.h
View File

@ -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