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

[Cedric Le Goater]

On 06/13/2014 01:52 PM, Alexander Graf wrote:
> 
> On 13.06.14 13:24, Greg Kurz wrote:
>> From: Rusty Russell <address@hidden>
>>
>> Signed-off-by: Rusty Russell <address@hidden>
>> Reviewed-by: Anthony Liguori <address@hidden>
>> [ pass VirtIODevice * to memory accessors,
>>    TCP checksums fix by Cédric Le Goater,
>>    Greg Kurz <address@hidden> ]
>> Cc: Cédric Le Goater <address@hidden>
>> Signed-off-by: Greg Kurz <address@hidden>
>> ---
>>   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?

That's a (possible) fix for virtio-net when vhost=off. It should probably 
be in another patch.

C.