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

[Greg Kurz <gkurz@linux.vnet.ibm.com>]

On Fri, 13 Jun 2014 14:24:47 +0200
Cedric Le Goater <clg@fr.ibm.com> wrote:

> On 06/13/2014 01:52 PM, Alexander Graf wrote:
> > 
> > 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?
> 
> That's a (possible) fix for virtio-net when vhost=off. It should probably 
> be in another patch.
> 
> C.
> 

Yeah you are right, this is a fix for a different issue. I'll simply drop these bits for now, and
send a standalone patch later.

-- 
Gregory Kurz                                     kurzgreg@fr.ibm.com
                                                 gkurz@linux.vnet.ibm.com
Software Engineer @ IBM/Meiosys                  http://www.ibm.com
Tel +33 (0)562 165 496

"Anarchy is about taking complete responsibility for yourself."
        Alan Moore.