| Message ID | 1464882211-18723-3-git-send-email-aconole@redhat.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
On Thu, Jun 02, 2016 at 11:43:31AM -0400, Aaron Conole wrote: > This patch checks the feature bit for the VIRTIO_NET_F_MTU feature. If it > exists, read the advised MTU and use it. > > No proper error handling is provided for the case where a user changes the > negotiated MTU. A future commit will add proper error handling. Instead, a > warning is emitted if the guest changes the device MTU after previously > being given advice. I don't see a warning and I don't think it's needed. Patch is ok commit log isn't. > Signed-off-by: Aaron Conole <aconole@redhat.com> > --- > drivers/net/virtio_net.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index e0638e5..ef5ee01 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -1896,6 +1896,12 @@ static int virtnet_probe(struct virtio_device *vdev) > if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) > vi->has_cvq = true; > > + if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) { > + dev->mtu = virtio_cread16(vdev, > + offsetof(struct virtio_net_config, > + mtu)); > + } > + > if (vi->any_header_sg) > dev->needed_headroom = vi->hdr_len; > > @@ -2067,6 +2073,7 @@ static unsigned int features[] = { > VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, > VIRTIO_NET_F_CTRL_MAC_ADDR, > VIRTIO_F_ANY_LAYOUT, > + VIRTIO_NET_F_MTU, > }; > > static struct virtio_driver virtio_net_driver = { > -- > 2.5.5
Hi Rick, In the future, please don't cut the list. Rick Jones <rick.jones2@hpe.com> writes: > On 06/02/2016 08:43 AM, Aaron Conole wrote: >> This patch checks the feature bit for the VIRTIO_NET_F_MTU feature. If it >> exists, read the advised MTU and use it. >> >> No proper error handling is provided for the case where a user changes the >> negotiated MTU. A future commit will add proper error handling. Instead, a >> warning is emitted if the guest changes the device MTU after previously >> being given advice. > > One of the things I've been doing has been setting-up a cluster > (OpenStack) with JumboFrames, and then setting MTUs on instance vNICs > by hand to measure different MTU sizes. It would be a shame if such a > thing were not possible in the future. Keeping a warning if shrinking > the MTU would be good, leave the error (perhaps) to if an attempt is > made to go beyond the advised value. This was cut because it didn't make sense for such a warning to be issued, but it seems like perhaps you may want such a feature? I agree with Michael, after thinking about it, that I don't know what sort of use the warning would serve. After all, if you're changing the MTU, you must have wanted such a change to occur? -Aaron > happy benchmarking, > > rick jones
"Michael S. Tsirkin" <mst@redhat.com> writes: > On Thu, Jun 02, 2016 at 11:43:31AM -0400, Aaron Conole wrote: >> This patch checks the feature bit for the VIRTIO_NET_F_MTU feature. If it >> exists, read the advised MTU and use it. >> >> No proper error handling is provided for the case where a user changes the >> negotiated MTU. A future commit will add proper error handling. Instead, a >> warning is emitted if the guest changes the device MTU after previously >> being given advice. > > I don't see a warning and I don't think it's needed. > Patch is ok commit log isn't. Okay, I'll fix it when I submit v2. >> Signed-off-by: Aaron Conole <aconole@redhat.com> >> --- >> drivers/net/virtio_net.c | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >> index e0638e5..ef5ee01 100644 >> --- a/drivers/net/virtio_net.c >> +++ b/drivers/net/virtio_net.c >> @@ -1896,6 +1896,12 @@ static int virtnet_probe(struct virtio_device *vdev) >> if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) >> vi->has_cvq = true; >> >> + if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) { >> + dev->mtu = virtio_cread16(vdev, >> + offsetof(struct virtio_net_config, >> + mtu)); >> + } >> + >> if (vi->any_header_sg) >> dev->needed_headroom = vi->hdr_len; >> >> @@ -2067,6 +2073,7 @@ static unsigned int features[] = { >> VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, >> VIRTIO_NET_F_CTRL_MAC_ADDR, >> VIRTIO_F_ANY_LAYOUT, >> + VIRTIO_NET_F_MTU, >> }; >> >> static struct virtio_driver virtio_net_driver = { >> -- >> 2.5.5
Hi,
[auto build test ERROR on next-20160602]
url: https://github.com/0day-ci/linux/commits/Aaron-Conole/virtio-net-Advised-MTU-feature/20160603-000714
config: i386-allmodconfig (attached as .config)
compiler: gcc-6 (Debian 6.1.1-1) 6.1.1 20160430
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
Note: the linux-review/Aaron-Conole/virtio-net-Advised-MTU-feature/20160603-000714 HEAD d909da4df3c52f78b4f5fcccd89aea5e38722d10 builds fine.
It only hurts bisectibility.
All errors (new ones prefixed by >>):
drivers/net/virtio_net.c: In function 'virtnet_probe':
>> drivers/net/virtio_net.c:1899:31: error: 'VIRTIO_NET_F_MTU' undeclared (first use in this function)
if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) {
^~~~~~~~~~~~~~~~
drivers/net/virtio_net.c:1899:31: note: each undeclared identifier is reported only once for each function it appears in
drivers/net/virtio_net.c: At top level:
>> drivers/net/virtio_net.c:2076:2: error: 'VIRTIO_NET_F_MTU' undeclared here (not in a function)
VIRTIO_NET_F_MTU,
^~~~~~~~~~~~~~~~
vim +/VIRTIO_NET_F_MTU +1899 drivers/net/virtio_net.c
1893 virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
1894 vi->any_header_sg = true;
1895
1896 if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1897 vi->has_cvq = true;
1898
> 1899 if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) {
1900 dev->mtu = virtio_cread16(vdev,
1901 offsetof(struct virtio_net_config,
1902 mtu));
1903 }
1904
1905 if (vi->any_header_sg)
1906 dev->needed_headroom = vi->hdr_len;
1907
1908 /* Use single tx/rx queue pair as default */
1909 vi->curr_queue_pairs = 1;
1910 vi->max_queue_pairs = max_queue_pairs;
1911
1912 /* Allocate/initialize the rx/tx queues, and invoke find_vqs */
1913 err = init_vqs(vi);
1914 if (err)
1915 goto free_stats;
1916
1917 #ifdef CONFIG_SYSFS
1918 if (vi->mergeable_rx_bufs)
1919 dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
1920 #endif
1921 netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
1922 netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
1923
1924 virtnet_init_settings(dev);
1925
1926 err = register_netdev(dev);
1927 if (err) {
1928 pr_debug("virtio_net: registering device failed\n");
1929 goto free_vqs;
1930 }
1931
1932 virtio_device_ready(vdev);
1933
1934 vi->nb.notifier_call = &virtnet_cpu_callback;
1935 err = register_hotcpu_notifier(&vi->nb);
1936 if (err) {
1937 pr_debug("virtio_net: registering cpu notifier failed\n");
1938 goto free_unregister_netdev;
1939 }
1940
1941 /* Assume link up if device can't report link status,
1942 otherwise get link status from config. */
1943 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1944 netif_carrier_off(dev);
1945 schedule_work(&vi->config_work);
1946 } else {
1947 vi->status = VIRTIO_NET_S_LINK_UP;
1948 netif_carrier_on(dev);
1949 }
1950
1951 pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
1952 dev->name, max_queue_pairs);
1953
1954 return 0;
1955
1956 free_unregister_netdev:
1957 vi->vdev->config->reset(vdev);
1958
1959 unregister_netdev(dev);
1960 free_vqs:
1961 cancel_delayed_work_sync(&vi->refill);
1962 free_receive_page_frags(vi);
1963 virtnet_del_vqs(vi);
1964 free_stats:
1965 free_percpu(vi->stats);
1966 free:
1967 free_netdev(dev);
1968 return err;
1969 }
1970
1971 static void remove_vq_common(struct virtnet_info *vi)
1972 {
1973 vi->vdev->config->reset(vi->vdev);
1974
1975 /* Free unused buffers in both send and recv, if any. */
1976 free_unused_bufs(vi);
1977
1978 free_receive_bufs(vi);
1979
1980 free_receive_page_frags(vi);
1981
1982 virtnet_del_vqs(vi);
1983 }
1984
1985 static void virtnet_remove(struct virtio_device *vdev)
1986 {
1987 struct virtnet_info *vi = vdev->priv;
1988
1989 unregister_hotcpu_notifier(&vi->nb);
1990
1991 /* Make sure no work handler is accessing the device. */
1992 flush_work(&vi->config_work);
1993
1994 unregister_netdev(vi->dev);
1995
1996 remove_vq_common(vi);
1997
1998 free_percpu(vi->stats);
1999 free_netdev(vi->dev);
2000 }
2001
2002 #ifdef CONFIG_PM_SLEEP
2003 static int virtnet_freeze(struct virtio_device *vdev)
2004 {
2005 struct virtnet_info *vi = vdev->priv;
2006 int i;
2007
2008 unregister_hotcpu_notifier(&vi->nb);
2009
2010 /* Make sure no work handler is accessing the device */
2011 flush_work(&vi->config_work);
2012
2013 netif_device_detach(vi->dev);
2014 cancel_delayed_work_sync(&vi->refill);
2015
2016 if (netif_running(vi->dev)) {
2017 for (i = 0; i < vi->max_queue_pairs; i++)
2018 napi_disable(&vi->rq[i].napi);
2019 }
2020
2021 remove_vq_common(vi);
2022
2023 return 0;
2024 }
2025
2026 static int virtnet_restore(struct virtio_device *vdev)
2027 {
2028 struct virtnet_info *vi = vdev->priv;
2029 int err, i;
2030
2031 err = init_vqs(vi);
2032 if (err)
2033 return err;
2034
2035 virtio_device_ready(vdev);
2036
2037 if (netif_running(vi->dev)) {
2038 for (i = 0; i < vi->curr_queue_pairs; i++)
2039 if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
2040 schedule_delayed_work(&vi->refill, 0);
2041
2042 for (i = 0; i < vi->max_queue_pairs; i++)
2043 virtnet_napi_enable(&vi->rq[i]);
2044 }
2045
2046 netif_device_attach(vi->dev);
2047
2048 rtnl_lock();
2049 virtnet_set_queues(vi, vi->curr_queue_pairs);
2050 rtnl_unlock();
2051
2052 err = register_hotcpu_notifier(&vi->nb);
2053 if (err)
2054 return err;
2055
2056 return 0;
2057 }
2058 #endif
2059
2060 static struct virtio_device_id id_table[] = {
2061 { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
2062 { 0 },
2063 };
2064
2065 static unsigned int features[] = {
2066 VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
2067 VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
2068 VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
2069 VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
2070 VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
2071 VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
2072 VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
2073 VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
2074 VIRTIO_NET_F_CTRL_MAC_ADDR,
2075 VIRTIO_F_ANY_LAYOUT,
> 2076 VIRTIO_NET_F_MTU,
2077 };
2078
2079 static struct virtio_driver virtio_net_driver = {
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
kbuild test robot <lkp@intel.com> writes: > Hi, > > [auto build test ERROR on next-20160602] > > url: https://github.com/0day-ci/linux/commits/Aaron-Conole/virtio-net-Advised-MTU-feature/20160603-000714 > config: i386-allmodconfig (attached as .config) > compiler: gcc-6 (Debian 6.1.1-1) 6.1.1 20160430 > reproduce: > # save the attached .config to linux build tree > make ARCH=i386 > > Note: the linux-review/Aaron-Conole/virtio-net-Advised-MTU-feature/20160603-000714 HEAD d909da4df3c52f78b4f5fcccd89aea5e38722d10 builds fine. > It only hurts bisectibility. > > All errors (new ones prefixed by >>): > > drivers/net/virtio_net.c: In function 'virtnet_probe': >>> drivers/net/virtio_net.c:1899:31: error: 'VIRTIO_NET_F_MTU' >>> undeclared (first use in this function) > if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) { > ^~~~~~~~~~~~~~~~ > drivers/net/virtio_net.c:1899:31: note: each undeclared identifier is reported only once for each function it appears in > drivers/net/virtio_net.c: At top level: >>> drivers/net/virtio_net.c:2076:2: error: 'VIRTIO_NET_F_MTU' >>> undeclared here (not in a function) > VIRTIO_NET_F_MTU, > ^~~~~~~~~~~~~~~~ Oops, hunk was dropped during rebase. Sorry for this, v2 will fix this error, as well and I'll do a boot test before submission. Thanks kbuild robot! > vim +/VIRTIO_NET_F_MTU +1899 drivers/net/virtio_net.c > > 1893 virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) > 1894 vi->any_header_sg = true; > 1895 > 1896 if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) > 1897 vi->has_cvq = true; > 1898 >> 1899 if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) { > 1900 dev->mtu = virtio_cread16(vdev, > 1901 offsetof(struct virtio_net_config, > 1902 mtu)); > 1903 } > 1904 > 1905 if (vi->any_header_sg) > 1906 dev->needed_headroom = vi->hdr_len; > 1907 > 1908 /* Use single tx/rx queue pair as default */ > 1909 vi->curr_queue_pairs = 1; > 1910 vi->max_queue_pairs = max_queue_pairs; > 1911 > 1912 /* Allocate/initialize the rx/tx queues, and invoke find_vqs */ > 1913 err = init_vqs(vi); > 1914 if (err) > 1915 goto free_stats; > 1916 > 1917 #ifdef CONFIG_SYSFS > 1918 if (vi->mergeable_rx_bufs) > 1919 dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group; > 1920 #endif > 1921 netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs); > 1922 netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs); > 1923 > 1924 virtnet_init_settings(dev); > 1925 > 1926 err = register_netdev(dev); > 1927 if (err) { > 1928 pr_debug("virtio_net: registering device failed\n"); > 1929 goto free_vqs; > 1930 } > 1931 > 1932 virtio_device_ready(vdev); > 1933 > 1934 vi->nb.notifier_call = &virtnet_cpu_callback; > 1935 err = register_hotcpu_notifier(&vi->nb); > 1936 if (err) { > 1937 pr_debug("virtio_net: registering cpu notifier failed\n"); > 1938 goto free_unregister_netdev; > 1939 } > 1940 > 1941 /* Assume link up if device can't report link status, > 1942 otherwise get link status from config. */ > 1943 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) { > 1944 netif_carrier_off(dev); > 1945 schedule_work(&vi->config_work); > 1946 } else { > 1947 vi->status = VIRTIO_NET_S_LINK_UP; > 1948 netif_carrier_on(dev); > 1949 } > 1950 > 1951 pr_debug("virtnet: registered device %s with %d RX and TX vq's\n", > 1952 dev->name, max_queue_pairs); > 1953 > 1954 return 0; > 1955 > 1956 free_unregister_netdev: > 1957 vi->vdev->config->reset(vdev); > 1958 > 1959 unregister_netdev(dev); > 1960 free_vqs: > 1961 cancel_delayed_work_sync(&vi->refill); > 1962 free_receive_page_frags(vi); > 1963 virtnet_del_vqs(vi); > 1964 free_stats: > 1965 free_percpu(vi->stats); > 1966 free: > 1967 free_netdev(dev); > 1968 return err; > 1969 } > 1970 > 1971 static void remove_vq_common(struct virtnet_info *vi) > 1972 { > 1973 vi->vdev->config->reset(vi->vdev); > 1974 > 1975 /* Free unused buffers in both send and recv, if any. */ > 1976 free_unused_bufs(vi); > 1977 > 1978 free_receive_bufs(vi); > 1979 > 1980 free_receive_page_frags(vi); > 1981 > 1982 virtnet_del_vqs(vi); > 1983 } > 1984 > 1985 static void virtnet_remove(struct virtio_device *vdev) > 1986 { > 1987 struct virtnet_info *vi = vdev->priv; > 1988 > 1989 unregister_hotcpu_notifier(&vi->nb); > 1990 > 1991 /* Make sure no work handler is accessing the device. */ > 1992 flush_work(&vi->config_work); > 1993 > 1994 unregister_netdev(vi->dev); > 1995 > 1996 remove_vq_common(vi); > 1997 > 1998 free_percpu(vi->stats); > 1999 free_netdev(vi->dev); > 2000 } > 2001 > 2002 #ifdef CONFIG_PM_SLEEP > 2003 static int virtnet_freeze(struct virtio_device *vdev) > 2004 { > 2005 struct virtnet_info *vi = vdev->priv; > 2006 int i; > 2007 > 2008 unregister_hotcpu_notifier(&vi->nb); > 2009 > 2010 /* Make sure no work handler is accessing the device */ > 2011 flush_work(&vi->config_work); > 2012 > 2013 netif_device_detach(vi->dev); > 2014 cancel_delayed_work_sync(&vi->refill); > 2015 > 2016 if (netif_running(vi->dev)) { > 2017 for (i = 0; i < vi->max_queue_pairs; i++) > 2018 napi_disable(&vi->rq[i].napi); > 2019 } > 2020 > 2021 remove_vq_common(vi); > 2022 > 2023 return 0; > 2024 } > 2025 > 2026 static int virtnet_restore(struct virtio_device *vdev) > 2027 { > 2028 struct virtnet_info *vi = vdev->priv; > 2029 int err, i; > 2030 > 2031 err = init_vqs(vi); > 2032 if (err) > 2033 return err; > 2034 > 2035 virtio_device_ready(vdev); > 2036 > 2037 if (netif_running(vi->dev)) { > 2038 for (i = 0; i < vi->curr_queue_pairs; i++) > 2039 if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL)) > 2040 schedule_delayed_work(&vi->refill, 0); > 2041 > 2042 for (i = 0; i < vi->max_queue_pairs; i++) > 2043 virtnet_napi_enable(&vi->rq[i]); > 2044 } > 2045 > 2046 netif_device_attach(vi->dev); > 2047 > 2048 rtnl_lock(); > 2049 virtnet_set_queues(vi, vi->curr_queue_pairs); > 2050 rtnl_unlock(); > 2051 > 2052 err = register_hotcpu_notifier(&vi->nb); > 2053 if (err) > 2054 return err; > 2055 > 2056 return 0; > 2057 } > 2058 #endif > 2059 > 2060 static struct virtio_device_id id_table[] = { > 2061 { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID }, > 2062 { 0 }, > 2063 }; > 2064 > 2065 static unsigned int features[] = { > 2066 VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, > 2067 VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC, > 2068 VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, > VIRTIO_NET_F_HOST_TSO6, > 2069 VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, > VIRTIO_NET_F_GUEST_TSO6, > 2070 VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO, > 2071 VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ, > 2072 VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN, > 2073 VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, > 2074 VIRTIO_NET_F_CTRL_MAC_ADDR, > 2075 VIRTIO_F_ANY_LAYOUT, >> 2076 VIRTIO_NET_F_MTU, > 2077 }; > 2078 > 2079 static struct virtio_driver virtio_net_driver = { > > --- > 0-DAY kernel test infrastructure Open Source Technology Center > https://lists.01.org/pipermail/kbuild-all Intel Corporation
On 06/02/2016 10:06 AM, Aaron Conole wrote: > Rick Jones <rick.jones2@hpe.com> writes: >> One of the things I've been doing has been setting-up a cluster >> (OpenStack) with JumboFrames, and then setting MTUs on instance vNICs >> by hand to measure different MTU sizes. It would be a shame if such a >> thing were not possible in the future. Keeping a warning if shrinking >> the MTU would be good, leave the error (perhaps) to if an attempt is >> made to go beyond the advised value. > > This was cut because it didn't make sense for such a warning to > be issued, but it seems like perhaps you may want such a feature? I > agree with Michael, after thinking about it, that I don't know what sort > of use the warning would serve. After all, if you're changing the MTU, > you must have wanted such a change to occur? I don't need a warning, was simply willing to live with one when shrinking the MTU. Didn't want an error. happy benchmarking, rick jones
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index e0638e5..ef5ee01 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1896,6 +1896,12 @@ static int virtnet_probe(struct virtio_device *vdev) if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) vi->has_cvq = true; + if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) { + dev->mtu = virtio_cread16(vdev, + offsetof(struct virtio_net_config, + mtu)); + } + if (vi->any_header_sg) dev->needed_headroom = vi->hdr_len; @@ -2067,6 +2073,7 @@ static unsigned int features[] = { VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, VIRTIO_NET_F_CTRL_MAC_ADDR, VIRTIO_F_ANY_LAYOUT, + VIRTIO_NET_F_MTU, }; static struct virtio_driver virtio_net_driver = {
This patch checks the feature bit for the VIRTIO_NET_F_MTU feature. If it exists, read the advised MTU and use it. No proper error handling is provided for the case where a user changes the negotiated MTU. A future commit will add proper error handling. Instead, a warning is emitted if the guest changes the device MTU after previously being given advice. Signed-off-by: Aaron Conole <aconole@redhat.com> --- drivers/net/virtio_net.c | 7 +++++++ 1 file changed, 7 insertions(+)