Re: [Qemu-devel] [PATCH v8 14/20] virtio-net: use virtio wrappers to access headers

[Alexander Graf <agraf@suse.de>]

On 13.06.14 13:24, Greg Kurz wrote:
> From: Rusty Russell <rusty@rustcorp.com.au>
>
> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
> Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
> [ pass VirtIODevice * to memory accessors,
>    TCP checksums fix by Cédric Le Goater,
>    Greg Kurz <gkurz@linux.vnet.ibm.com> ]
> Cc: Cédric Le Goater <clg@fr.ibm.com>
> Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
> ---
>   hw/net/virtio-net.c |   34 +++++++++++++++++++++++++++-------
>   1 file changed, 27 insertions(+), 7 deletions(-)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 58e7b73..fb17919 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -23,6 +23,7 @@
>   #include "hw/virtio/virtio-bus.h"
>   #include "qapi/qmp/qjson.h"
>   #include "monitor/monitor.h"
> +#include "hw/virtio/virtio-access.h"
>   
>   #define VIRTIO_NET_VM_VERSION    11
>   
> @@ -72,8 +73,8 @@ static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config)
>       VirtIONet *n = VIRTIO_NET(vdev);
>       struct virtio_net_config netcfg;
>   
> -    stw_p(&netcfg.status, n->status);
> -    stw_p(&netcfg.max_virtqueue_pairs, n->max_queues);
> +    virtio_stw_p(vdev, &netcfg.status, n->status);
> +    virtio_stw_p(vdev, &netcfg.max_virtqueue_pairs, n->max_queues);
>       memcpy(netcfg.mac, n->mac, ETH_ALEN);
>       memcpy(config, &netcfg, n->config_size);
>   }
> @@ -611,6 +612,7 @@ static int virtio_net_handle_offloads(VirtIONet *n, uint8_t cmd,
>   static int virtio_net_handle_mac(VirtIONet *n, uint8_t cmd,
>                                    struct iovec *iov, unsigned int iov_cnt)
>   {
> +    VirtIODevice *vdev = VIRTIO_DEVICE(n);
>       struct virtio_net_ctrl_mac mac_data;
>       size_t s;
>       NetClientState *nc = qemu_get_queue(n->nic);
> @@ -639,7 +641,7 @@ static int virtio_net_handle_mac(VirtIONet *n, uint8_t cmd,
>   
>       s = iov_to_buf(iov, iov_cnt, 0, &mac_data.entries,
>                      sizeof(mac_data.entries));
> -    mac_data.entries = ldl_p(&mac_data.entries);
> +    mac_data.entries = virtio_ldl_p(vdev, &mac_data.entries);
>       if (s != sizeof(mac_data.entries)) {
>           goto error;
>       }
> @@ -666,7 +668,7 @@ static int virtio_net_handle_mac(VirtIONet *n, uint8_t cmd,
>   
>       s = iov_to_buf(iov, iov_cnt, 0, &mac_data.entries,
>                      sizeof(mac_data.entries));
> -    mac_data.entries = ldl_p(&mac_data.entries);
> +    mac_data.entries = virtio_ldl_p(vdev, &mac_data.entries);
>       if (s != sizeof(mac_data.entries)) {
>           goto error;
>       }
> @@ -706,12 +708,13 @@ error:
>   static int virtio_net_handle_vlan_table(VirtIONet *n, uint8_t cmd,
>                                           struct iovec *iov, unsigned int iov_cnt)
>   {
> +    VirtIODevice *vdev = VIRTIO_DEVICE(n);
>       uint16_t vid;
>       size_t s;
>       NetClientState *nc = qemu_get_queue(n->nic);
>   
>       s = iov_to_buf(iov, iov_cnt, 0, &vid, sizeof(vid));
> -    vid = lduw_p(&vid);
> +    vid = virtio_lduw_p(vdev, &vid);
>       if (s != sizeof(vid)) {
>           return VIRTIO_NET_ERR;
>       }
> @@ -748,7 +751,7 @@ static int virtio_net_handle_mq(VirtIONet *n, uint8_t cmd,
>           return VIRTIO_NET_ERR;
>       }
>   
> -    queues = lduw_p(&mq.virtqueue_pairs);
> +    queues = virtio_lduw_p(vdev, &mq.virtqueue_pairs);
>   
>       if (queues < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
>           queues > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
> @@ -863,6 +866,14 @@ static int virtio_net_has_buffers(VirtIONetQueue *q, int bufsize)
>       return 1;
>   }
>   
> +static void virtio_net_hdr_swap(VirtIODevice *vdev, struct virtio_net_hdr *hdr)
> +{
> +    virtio_tswap16s(vdev, &hdr->hdr_len);
> +    virtio_tswap16s(vdev, &hdr->gso_size);
> +    virtio_tswap16s(vdev, &hdr->csum_start);
> +    virtio_tswap16s(vdev, &hdr->csum_offset);
> +}
> +
>   /* dhclient uses AF_PACKET but doesn't pass auxdata to the kernel so
>    * it never finds out that the packets don't have valid checksums.  This
>    * causes dhclient to get upset.  Fedora's carried a patch for ages to
> @@ -898,6 +909,7 @@ static void receive_header(VirtIONet *n, const struct iovec *iov, int iov_cnt,
>           void *wbuf = (void *)buf;
>           work_around_broken_dhclient(wbuf, wbuf + n->host_hdr_len,
>                                       size - n->host_hdr_len);
> +        virtio_net_hdr_swap(VIRTIO_DEVICE(n), wbuf);
>           iov_from_buf(iov, iov_cnt, 0, buf, sizeof(struct virtio_net_hdr));
>       } else {
>           struct virtio_net_hdr hdr = {
> @@ -1047,7 +1059,7 @@ static ssize_t virtio_net_receive(NetClientState *nc, const uint8_t *buf, size_t
>       }
>   
>       if (mhdr_cnt) {
> -        stw_p(&mhdr.num_buffers, i);
> +        virtio_stw_p(vdev, &mhdr.num_buffers, i);
>           iov_from_buf(mhdr_sg, mhdr_cnt,
>                        0,
>                        &mhdr.num_buffers, sizeof mhdr.num_buffers);
> @@ -1106,6 +1118,14 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q)
>               exit(1);
>           }
>   
> +        if (n->has_vnet_hdr) {
> +            if (out_sg[0].iov_len < n->guest_hdr_len) {
> +                error_report("virtio-net header incorrect");
> +                exit(1);
> +            }
> +            virtio_net_hdr_swap(vdev, (void *) out_sg[0].iov_base);

Where does this come from? If you're doing twap() wouldn't that have 
been broken before too?


Alex