If the host uses packet encapsulation feature, the MTU may be reduced by the
host due to headroom reservation for encapsulation. This patch handles this
new MTU value.
Signed-off-by: Haiyang Zhang <haiya...@microsoft.com>
---
drivers/net/hyperv/netvsc.c | 3 ++-
drivers/net/hyperv/netvsc_drv.c | 5 +++--
drivers/net/hyperv/rndis_filter.c | 9 +++++++++
3 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 7d76c95..6b46311 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -440,7 +440,8 @@ static int negotiate_nvsp_ver(struct hv_device *device,
/* NVSPv2 only: Send NDIS config */
memset(init_packet, 0, sizeof(struct nvsp_message));
init_packet->hdr.msg_type = NVSP_MSG2_TYPE_SEND_NDIS_CONFIG;
- init_packet->msg.v2_msg.send_ndis_config.mtu = net_device->ndev->mtu;
+ init_packet->msg.v2_msg.send_ndis_config.mtu = net_device->ndev->mtu +
+ ETH_HLEN;
init_packet->msg.v2_msg.send_ndis_config.capability.ieee8021q = 1;
ret = vmbus_sendpacket(device->channel, init_packet,
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 3295e4e..15d82ed 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -699,9 +699,10 @@ static int netvsc_change_mtu(struct net_device *ndev, int
mtu)
return -ENODEV;
if (nvdev->nvsp_version >= NVSP_PROTOCOL_VERSION_2)
- limit = NETVSC_MTU;
+ limit = NETVSC_MTU - ETH_HLEN;
- if (mtu < 68 || mtu > limit)
+ /* Hyper-V hosts don't support MTU < ETH_DATA_LEN (1500) */
+ if (mtu < ETH_DATA_LEN || mtu > limit)
return -EINVAL;
nvdev->start_remove = true;
diff --git a/drivers/net/hyperv/rndis_filter.c
b/drivers/net/hyperv/rndis_filter.c
index ccce6f2..7b2c5d1 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -998,6 +998,7 @@ int rndis_filter_device_add(struct hv_device *dev,
int t;
struct ndis_recv_scale_cap rsscap;
u32 rsscap_size = sizeof(struct ndis_recv_scale_cap);
+ u32 mtu, size;
rndis_device = get_rndis_device();
if (!rndis_device)
@@ -1029,6 +1030,14 @@ int rndis_filter_device_add(struct hv_device *dev,
return ret;
}
+ /* Get the MTU from the host */
+ size = sizeof(u32);
+ ret = rndis_filter_query_device(rndis_device,
+ RNDIS_OID_GEN_MAXIMUM_FRAME_SIZE,
+ &mtu, &size);
+ if (ret == 0 && size == sizeof(u32))
+ net_device->ndev->mtu = mtu;
+
/* Get the mac address */
ret = rndis_filter_query_device_mac(rndis_device);
if (ret != 0) {
--
1.7.1
--
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